Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

i

Table of Contents

ii

Table of Contents

iii

Table of Contents

iv

Table of Contents

v

QUESTIONS AND ANSWERS

The following are some of the questions you, as a shareholder of Songa Offshore SE, may have and answers to those questions. These questions and answers are not meant to be a substitute for the information contained in the remainder of this Prospectus because the information in this section does not provide all the important information regarding the Offer. We urge you to read this document in its entirety prior to making any decision as to the matters described in this Prospectus. In this Prospectus, unless otherwise specified, the terms “we,” “our,” “us,” “Company,” and “Transocean” refer to Transocean Ltd,. or Transocean Ltd. together with its subsidiaries, as the context requires.

Q:  WHAT IS TRANSOCEAN PROPOSING?

A:   Transocean has entered into an agreement with Songa Offshore pursuant to which Transocean intends to acquire all of the issued and outstanding Songa Shares (on a fully diluted basis) through a voluntary tender offer, which we refer to as the Offer, as described in further detail below. In the Offer, Transocean is offering to exchange, for each Songa Share, a combination of (i) 0.35724 Consideration Shares issued by Transocean and (ii) USD 2.99726 principal amount of Exchangeable Bonds of TINC, a wholly-owned subsidiary of Transocean, which are exchangeable into Shares. As part of the Offer, each shareholder of Songa Offshore may instead elect to receive cash of NOK 47.50 per Songa Share up to a maximum of NOK 125,000 per shareholder. The aggregate consideration to be paid to each Songa Offshore shareholder accepting the Offer shall be comprised, as nearly as possible, of 50% Consideration Shares and 50% Exchangeable Bonds, with any exercise by such shareholder of the Cash Election being deducted first from the aggregate principal amount of Exchangeable Bonds otherwise issuable to such shareholder and second from the aggregate number of Consideration Shares otherwise issuable to such shareholder. After completing the Offer and acquiring 90% or more of the voting rights of Songa Offshore, Transocean intends to initiate a compulsory “squeeze-out” acquisition of the remaining Songa Shares not owned by Transocean pursuant to the Cyprus Takeover Bids Law. A copy of the Transaction Agreement is attached hereto as Annex A and is incorporated by reference herein.

Songa Offshore shareholders may tender Songa Shares in the Offer as set forth in this Prospectus.

Q:  WHO IS MAKING THE OFFER?

A:   This Offer is being made by Transocean Ltd.

Q:  WHY IS TRANSOCEAN MAKING THE OFFER?

A:   Transocean believes that the Combination will benefit Transocean shareholders. See “Background and Reasons for the Combination” for further detail.

Q:  WHAT WILL SONGA OFFSHORE SHAREHOLDERS RECEIVE IN EXCHANGE FOR SONGA SHARES?

A:   Transocean will offer, upon the terms and subject to the conditions described in this Prospectus, to exchange each Songa Share that is validly tendered and not properly withdrawn, for:

As part of the Offer, each Songa Offshore shareholder may instead elect to receive up to NOK 125,000 in cash pursuant to the Cash Election in lieu of some or all of the Consideration Shares and Exchangeable Bonds such shareholder would otherwise be entitled to receive in the Offer.

The aggregate consideration to be paid to each Songa Offshore shareholder accepting the Offer shall be comprised, as nearly as possible, of 50% Consideration Shares and 50% Exchangeable Bonds, with any exercise by such shareholder of the Cash Election being deducted first from the aggregate principal amount of Exchangeable Bonds otherwise issuable to such shareholder and second from the aggregate number of Consideration Shares otherwise issuable to such shareholder.

Based on the closing price of USD 9.51 for the Shares on the NYSE on November 19, 2017 and an exchange rate of 8.2552 NOK per USD, which is the NOK/USD exchange rate on November 19, 2017 as determined by Norges Bank, the aggregate value of the Consideration to be received per Songa Share is NOK 50.94, assuming all Exchangeable Bonds received in the Offer are immediately converted into Transocean shares.  By comparison, the closing price of the Songa Shares on the Oslo Stock Exchange on November 19, 2017 was NOK 54.50.

Holders may exchange their Exchangeable Bonds for Shares at any time prior to the close of business on the business day immediately preceding the maturity date. The initial exchange rate of the Exchangeable Bonds is 97.29756 Shares per USD 1,000 principal amount of Exchangeable Bonds. See “Description of Transocean Exchangeable Bonds–Exchange Rights.”

Transocean will not issue any fractional Consideration Shares or fractional amounts of Exchangeable Bonds (each of which has a principal amount of USD 1,000) in the Offer. Each Songa Offshore shareholder who accepts the Offer and, following the completion of the Offer, any Songa Offshore shareholder in connection with a subsequent mandatory offer or compulsory acquisition (squeeze-out) (a) who would otherwise be entitled to receive a fraction of a Consideration Share will instead receive, for the fraction of a Consideration Share, an amount in cash based on USD 8.39, the closing price of the Consideration Shares on the NYSE on August 14, 2017, the last trading day prior to the announcement of the proposed Combination and Offer (the “Reference Price”), and (b) who would otherwise be entitled to receive a fractional amount of Exchangeable Bonds will instead receive, for the fractional amount of Exchangeable Bonds, an amount in cash based on USD 1,000, the principal amount per Exchangeable Bond, and in each case, paid in NOK, based on an exchange rate of 7.9239 NOK per U.S. dollar which is the NOK/USD closing price at 4:00 p.m. CET as determined by Norges Bank, on August 14, 2017, the trading day immediately preceding the announcement of the Offer.

We refer to the value of any cash and the value of the aggregate number of Consideration Shares and Exchangeable Bonds to be delivered per Songa Offshore shareholder as the “Offer Price.”

Q:  HOW LONG DO SONGA OFFSHORE SHAREHOLDERS HAVE TO DECIDE WHETHER TO TENDER?

A:   The shareholders of Songa Offshore may accept the Offer in the period from and including December 21, 2017 to and including January 23, 2018 at 4:30 p.m. (CET), as extended from time to time (the “Offer Period”). Transocean may, in its sole discretion, extend the Offer Period (one or more times), however, the Offer Period may not be extended beyond 11:59 p.m. (CET) on February 15, 2018. References to the Offer Period in this Prospectus refer to the Offer Period as extended from time to time. If the Offer Period is extended, the other dates referred to in this section may be changed accordingly and any acceptance forms (“Acceptance Forms”) received will remain binding and irrevocable for the length of the extension.

Q:  WHAT IS THE PROCEDURE FOR TENDERING SONGA SHARES?

A:   Songa Offshore shareholders who wish to accept the Offer must complete and sign the acceptance form enclosed with this Prospectus as Annex B and return it to the Settlement Agent prior to the expiration of the Offer Period. Acceptances may be revoked until the end of the Offer Period.

Q:  UNTIL WHAT TIME CAN TENDERED SONGA SHARES BE WITHDRAWN?

A:   The acceptance of the Offer is binding once the Settlement Agent has received the acceptance form, except as otherwise required by applicable law. Prior to the expiration of the Offer, Songa Offshore shareholders may withdraw any shares tendered in the Offer. At the end of the Offer Period, withdrawal rights will cease, and any Songa Shares tendered in the Offer cannot be withdrawn. If the Offer Period is extended, Songa Offshore shareholders may withdraw their shares until the end of the Offer Period as extended. Shareholders that accept the Offer will remain the beneficial owners of their Songa Shares and retain voting rights related thereto until settlement has taken place.

Q:  WHAT IS THE PROCEDURE TO WITHDRAW PREVIOUSLY TENDERED SONGA SHARES?

A:   To withdraw previously tendered Songa Shares (except for pre-acceptance undertakings, which have no withdrawal rights unless the Offer is terminated), a written notice of withdrawal included as Annex C must, prior to the expiration of the Offer Period, be timely received by the Settlement Agent. The written notice of withdrawal must specify the number of Songa Shares withdrawn and instruct the Settlement Agent holding the shares to release the blocking on the VPS account specified by the withdrawing shareholder.

Q:  CAN TENDERED SONGA SHARES BE TRADED?

A:   No. By giving a duly executed acceptance form to the Settlement Agent, Songa Offshore shareholders give an authorization to block the Songa Shares to which the acceptance form relates, in favor of the Settlement Agent, who is authorized to transfer validly tendered Songa Shares to Transocean. As consideration for the contribution of Songa Shares, Transocean will issue the Consideration Shares, cause TINC to issue the Exchangeable Bonds and, subject to an election of Songa Offshore shareholders, pay cash for the purposes of the settlement at the completion of the Offer. It is not possible for shareholders to dispose of the Songa

Shares when they are blocked, although such shareholders will, to the extent permitted under Norwegian law, remain the legal owners of their Songa Shares and retain voting rights and other shareholder rights associated with such tendered shares until settlement occurs. Additionally, tendering Songa Offshore shareholders are free to dispose of any other securities not registered in the same VPS-account as the blocked Songa Shares. In the event the Offer is cancelled, the blocking will be terminated. 

Q:  CAN THE OFFER BE EXTENDED AND, IF SO, UNDER WHAT CIRCUMSTANCES?

A:   Unless the Transaction Agreement has been terminated, Transocean will extend the Offer for any period required by applicable U.S. federal securities laws and the rules and regulations of the SEC, the NYSE, the Oslo Stock Exchange, applicable Norwegian law or applicable laws and regulations of Cyprus, but in no event will Transocean be required to extend the Offer past 11:59 p.m. (CET) on February 15, 2018. Additionally, if at any scheduled date of expiration of the Offer, the closing conditions described under “Terms of the Offer—Conditions for Completion of the Offer” have not been satisfied or waived, Transocean may elect to, and will if reasonably requested by Songa Offshore, extend the Offer to a date that is not more than ten U.S. business days after such previously scheduled date of expiration, provided, however, that if as of any date of expiration, conditions in items (1) and (2) under “Terms of the Offer—Conditions for Completion of the Offer” have not been satisfied or waived, Transocean may elect to, and will if reasonably requested by Songa Offshore, extend the Offer (to the extent legally permissible under applicable law) to a date that is not more than twenty U.S. business days after the then-scheduled date of expiration, which date shall in no event be later than 11:59 p.m. (CET) on February 15, 2018, which we refer to as the Long Stop Date (as extended, if applicable, at the election of Transocean one time for no more than 25 U.S. business days), for the purpose of soliciting additional proxies from shareholders for the election of the chairman of the board of directors of Songa Offshore to the board of directors of Transocean. References in this Prospectus to the Long Stop Date refer to the Long Stop Date as extended from time to time.

Q:  HOW WILL SONGA OFFSHORE SHAREHOLDERS BE NOTIFIED IF THE OFFER IS EXTENDED?

A:   Transocean will publish any notices of extension of the Offer Period by notification to the Oslo Stock Exchange. Notices will be deemed made when the Oslo Stock Exchange has published the notice through its information system. Transocean will without undue delay notify the Oslo Stock Exchange if the conditions of the Offer are met or waived or if the Offer is cancelled. Transocean will also issue a press release and otherwise comply with its obligations under U.S. law with respect to informing security holders of any material change in the information published, sent or given to security holders.

Q:  WHAT ARE THE CONDITIONS TO THE OFFER?

A:   The Offer will be subject to a number of conditions, including:

For more information on the conditions to the Offer, see “Terms of the Offer—Conditions for Completion of the Offer.” If the Offer has not become unconditional by the Long Stop Date (i.e., if all conditions have not been satisfied or waived, where permissible), the Offer will lapse and any tendered shares will be released by the Settlement Agent and returned to the relevant tendering shareholder.

Q:  WHEN DO YOU EXPECT THE OFFER TO BE COMPLETED AND WHEN WILL THE OFFER CONSIDERATION BE PAID?

A:   The timing for consummation of the Offer will depend on the satisfaction of the conditions to the Offer. As a result, there can be no certainty as to when, and whether, Transocean will be able to complete the Offer. If any of the conditions to the Offer have not been satisfied or, where permissible, waived, on or prior to 11:59 p.m. (CET) on the Long Stop Date, then the Offer will terminate. The conditions to the Offer are discussed in “Terms of the Offer—Conditions for Completion of the Offer.”

If the Offer is consummated, then Songa Offshore shareholders who validly tender during the Offer Period and do not properly withdraw their tendered Songa Shares will receive the Consideration Shares, Exchangeable Bonds and/or cash, as applicable, in settlement of the Offer promptly following the expiration of the Offer Period and, in any case, no later than 15 business days following the expiration of the Offer Period. We expect such settlement to occur within five business days following the expiration of the Offer Period.

The result of the Offer is expected to be published no later than the next business day following the expiration of the Offer Period.

After the expiration of the Offer Period, Songa Offshore shareholders may not withdraw their tendered shares. If the Offer is not completed, shareholders who have tendered their Songa Shares in the Offer will have the blocking of their shares terminated within three U.S. business days.

Q:  HOW WILL THE SONGA SHARES HELD BY SONGA OFFSHORE SHAREHOLDERS WHO DO NOT TENDER THEIR SHARES BE AFFECTED FOLLOWING THE OFFER?

A:   Following the completion of the Offer, the trading market for any remaining Songa Shares not exchanged in the Offer may be substantially limited compared with historic trading levels. As a result, the price for Songa Shares in the secondary market may decline following the completion of the Offer. Holders of Songa Shares who do not participate in the Offer may not be able to sell their Songa Shares at a favorable price, if at all, following the completion of the Offer.

In addition, Transocean intends to promptly apply to conduct a compulsory acquisition (squeeze-out) under the Cyprus Takeover Bids Law following completion of the Offer. However, Transocean may not be able to complete such a compulsory acquisition in a prompt manner, if at all. In addition, the tax treatment of the Exchangeable Bonds issued in the compulsory acquisition may differ from the tax treatment of the Exchangeable Bonds issued in the Offer. In that case any Exchangeable Bonds issued in the compulsory acquisition may not be fungible for trading purposes with Exchangeable Bonds issued in the Offer and may therefore trade in the secondary market at a lower price than Exchangeable Bonds issued in the Offer, and any such secondary market for Exchangeable Bonds issued in the compulsory acquisition may be significantly less liquid than any secondary market for Exchangeable Bonds issued in the Offer.

For a more complete discussion on potential consequences in the event that you decide not to tender your Songa Shares, see “Risk Factors—Risks Factors Related to the Offer.”

Q:  HAVE ANY SONGA OFFSHORE SHAREHOLDERS COMMITTED TO TENDER THEIR SHARES IN THE OFFER?

A:   In connection with the execution of the Transaction Agreement, Transocean obtained irrevocable undertakings from Songa Offshore shareholders beneficially owning approximately 76.5% of the Songa Shares (on a fully diluted basis) to tender their shares in the Offer, including a commitment from Songa Offshore’s largest shareholder, Perestroika AS. For further detail, see “Terms of the Offer—Pre-acceptance Undertakings.”

Based on the number of Songa Shares outstanding as of December 11, 2017, in order to satisfy the condition that Songa Offshore shareholders holding a number of Songa Shares representing more than 90% of the total share capital of Songa Offshore, on a fully diluted basis, shall in the aggregate have accepted the Offer, a total of 172,898,969 Songa Shares must be tendered in the Offer. We expect that 146,931,658 Songa Shares will be tendered in the Offer pursuant to the pre-acceptance agreements received by Transocean, meaning that an additional 25,967,311 Songa Shares must be tendered to satisfy this condition.

Q:  HOW WILL SONGA OFFSHORE SHAREHOLDERS BE AFFECTED IN THE EVENT OF A SQUEEZE-OUT TRANSACTION?

A:   In the event of any “squeeze-out” transaction in which Transocean acquires the remaining Songa Shares not tendered in the Offer, such Songa Shares would be automatically converted into the right to receive adequate compensation as determined under the Cyprus Takeover Bids Law.

If the Offer is completed and Transocean, as a result of the Offer or otherwise, or any person acting in concert with Transocean, becomes the owner of Songa Shares representing more than 30% of the outstanding voting rights, Transocean will be required under Section 13 of the Cyprus Takeover Bids Law to make a mandatory offer for the remaining shares, unless Transocean, following completion of the Offer, holds at least 90% of the shares and votes in Songa Offshore and within three months resolves a compulsory acquisition (squeeze-out). The offer price for such mandatory offer must be equal to, or higher than, the highest price paid, or agreed to be paid, by Transocean or any person acting in concert with Transocean for the Songa Shares during the six-month period prior to the date on which the obligation to make a mandatory offer is triggered. If, as a result of the Offer or a subsequent mandatory offer,, Transocean acquires and holds 90% or more of the total issued Songa Shares representing 90% or more of the voting rights in Songa Offshore, Transocean intends to promptly carry out a compulsory acquisition of the remaining Songa Shares in accordance with the procedures outlined above. In accordance with Section 36(3) of the Cyprus Takeover Bids Law, the consideration to be offered in case of a compulsory acquisition should be in the same form and at least equal to the consideration given in the Offer, while in any case cash consideration must be offered as an alternative. See “Terms of the Offer—Additional Information—Mandatory Offer” and “Terms of the Offer—Additional Information—Compulsory Acquisition.”

Q:  HOW WILL REMAINING SONGA OFFSHORE SHAREHOLDERS BE AFFECTED IN THE EVENT THAT TRANSOCEAN IS UNABLE TO AFFECT A SQUEEZE-OUT TRANSACTION FOLLOWING COMPLETION OF THE OFFER?

A:   Unless we elect to waive the minimum tender condition, upon completion of the Offer, we will be the owner of Songa Shares representing more than 90% of the outstanding voting rights of Songa Offshore and intend to initiate a compulsory acquisition (squeeze-out) within three months following completion of the the Offer as described in “—Compulsory Acquisition” below.  If we elect to waive the minimum tender condition, we will extend the Offer and disseminate revised offer materials containing disclosure about the waiver and the impact of the lower acceptance level on the combined entity after the Offer. If the Offer is completed and Transocean, as a result of the Offer or otherwise, or any person acting in concert with Transocean, becomes the owner of Songa Shares representing more than 30% of the outstanding voting rights but less than 90%, Transocean will be required under Section 13 of the Cyprus Takeover Bids Law to make a mandatory cash offer for the remaining shares. See “—Mandatory Offer” below for further information on the applicable mandatory offer rules. A subsequent mandatory offer must include a cash alternative but is not required to include consideration in Consideration Shares and/or Exchangeable Bonds.

Transocean may seek a delisting of the shares of Songa Offshore from the Oslo Stock Exchange even if it does not hold 90% or more of the shares and voting rights in Songa Offshore following completion of the Offer. If Transocean no longer considers the listing of Songa Offshore's shares on the Oslo Stock Exchange appropriate, it may propose at a general meeting of Songa Offshore that the company apply for delisting of its shares from the Oslo Stock Exchange. Although there is no minimum requirement as to the percentage of shares and voting rights Transocean must hold in Songa Offshore, an application for delisting requires the approval of the same majority as required to amend Songa’s Articles of Association at a general meeting, which is 75% of votes present.  See “—Delisting from Oslo Stock Exchange” below for further information. An application for delisting will be approved or rejected by the Oslo Stock Exchange in

accordance with the stock exchange rules, taking into account, among other things, the interests of minority shareholders. Whether an application for delisting will be approved in the event Transocean holds less than 90% of the shares in Songa Offshore is therefore uncertain. A delisting would not trigger a mandatory offer, squeeze-out or sell-out right under Norwegian law.

For as long as Songa Offshore remains listed, Songa Offshore will be subject to the Oslo Stock Exchange continuing obligations and the applicable requirements of the Norwegian Securities Trading Act of 29 June 2007 no. 75 (the “Norwegian Securities Trading Act”) and related secondary regulation, which imposes requirements on Songa Offshore to the benefit of remaining Songa Offshore shareholders, including, among others, financial and other reporting obligations and the duty to observe the principle of equal treatment of shareholders.

Q:  WHAT ARE THE RIGHTS OF REMAINING SONGA OFFSHORE SHAREHOLDERS IN THE EVENT TRANSOCEAN IS UNABLE TO EFFECT A SQUEEZE-OUT TRANSACTION FOLLOWING COMPLETION OF THE OFFER?

If the Offer is completed and Transocean does not hold 90% or more of the shares and voting rights in Songa Offshore, the Cypress Takeover Bids Law does not provide for any other means of compulsory acquisition or any squeeze-out rights if ownership levels are below 90%. Any remaining Songa Offshore shareholders will retain their existing rights, including preemptive rights, the right to receive dividends, transfer rights, rights to participate in Annual General Meetings of Songa Offshore (including the right to vote for directors and the right to participate in meetings convened for the purposes of alteration of Songa Offshore’s capital), liquidation rights and statutory inspection rights. For a complete discussion of these rights, see the discussions of the rights of Songa Offshore shareholders in “Comparison of Shareholder Rights.”

Q:  ARE APPRAISAL RIGHTS AVAILABLE IN THE COMBINATION?

A:   There are no appraisal rights relevant to the Offer under Norwegian or Cyprus law.In the event of a squeeze-out transaction following completion of the Offer, Cyprus law would provide for certain rights for the remaining 10% or fewer Songa Offshore shareholders. For more information, see “Comparison of Shareholder Rights—Appraisal Rights and Compulsory Acquisitions.”

Q:  WHAT WILL HAPPEN TO SONGA RESTRICTED STOCK UNITS IN THE OFFER?

A:   Certain members of the management of Songa Offshore own unvested restricted stock units that will accelerate in connection with the Offer. We currently expect that prior to the expiration of the Offer, the vesting of all unvested restricted stock rights held by Songa Offshore shareholders under the Songa Offshore Long-Term Incentive Plan will be accelerated, and these shares may be tendered in the Offer on the same basis as other Songa Shares. For more information see “Material Interests of Songa Offshore’s Board and Management in the Combination.”

Q:  WILL SONGA OFFSHORE SHAREHOLDERS BE OBLIGATED TO PAY ANY FEES OR COMMISSIONS TO EXCHANGE SONGA SHARES?

A:   Songa Offshore shareholders who hold their Songa Shares in Norwegian custody accounts will not incur any fees and expenses in connection with tendering their Songa Shares in the Offer (except for the costs of transmitting the declaration of acceptance to their custodian bank).

Q:  WILL SONGA OFFSHORE SHAREHOLDERS BE SUBJECT TO UNITED STATES FEDERAL INCOME TAX ON THE CONSIDERATION SHARES, EXCHANGEABLE BONDS AND CASH RECEIVED IN THE EXCHANGE OFFER?

A:   The exchange of Songa Shares for Shares, Exchangeable Bonds and, if elected, cash pursuant to the Offer will be a taxable transaction for United States federal income tax purposes. U.S. holders (as defined in “Material Tax Considerations—United States Taxation”) of Songa Shares generally will recognize gain or loss equal to the difference, if any, between (i) the sum of (A) the fair market value of any Shares received in exchange for such Songa Shares, determined in U.S. dollars, plus (B) the issue price, as determined for United States federal income tax purposes, of the Exchangeable Bonds received in exchange for such Songa Shares, plus (C) the U.S. dollar amount of any cash received in Norwegian kroner in exchange for such Songa Shares, plus (D) any cash received in lieu of any fractional Consideration Shares or Exchangeable Bonds and (ii) such U.S. holder’s adjusted tax basis in the Songa Shares. Provided that Songa Offshore is not treated as a passive foreign investment company for U.S. federal income tax purposes, any gain or loss recognized upon the exchange generally will be treated as capital gain or loss.

A non-U.S. holder (as defined in “Material Tax Considerations—United States Taxation”) will generally not be subject to United States federal income tax on gain recognized on exchange of Songa Shares pursuant to the exchange offer unless the gain is “effectively connected” with the non-U.S. holder’s conduct of a trade or business in the United States or the non-U.S. holder is an individual present in the United States for 183 or more days in the taxable year of the exchange, and certain other requirements are met.

The foregoing is a brief summary of United States federal income tax consequences only and is qualified by the description of United States federal income tax considerations in “Material Tax Considerations—United States Taxation.” Tax matters are very complicated, and the tax consequences of the exchange offer to a particular holder will depend in part on such holder’s circumstances. Accordingly, holders of Songa Shares are urged to consult their own tax advisors for a full understanding of the tax consequences of the exchange offer to them, including the applicability of United States federal, state, local and foreign income and other tax laws.

Q:  WILL SONGA OFFSHORE SHAREHOLDERS BE SUBJECT TO NORWEGIAN TAXATION ON THE SHARES, EXCHANGEABLE BONDS AND CASH RECEIVED IN THE OFFER?

A:   The exchange of Songa Shares for Shares, Exchangeable Bonds and cash pursuant to the Offer will be a taxable transaction for Norwegian income tax purposes for individual shareholders, while for corporate shareholders the transaction is expected to normally be tax exempt under the Norwegian exemption method. Norwegian individual holders (see “Material Tax Considerations—Norwegian Taxation—The Exchange of Songa Shares for Consideration”) of Songa Shares generally will recognize gain or loss equal

to the difference, if any, between (i) the sum of (A) the fair market value of any Shares received in exchange for such Songa Shares, determined in NOK, plus (B) the issue price, as determined for Norwegian income tax purposes, of the Exchangeable Bonds received in the Offer, plus (C) the amount of any cash received in Norwegian kroner received in the Offer and (ii) such individual Norwegian holder’s tax basis in the Songa Shares exchanged. Any gain or loss recognized by a Norwegian holder in connection with the Offer generally will be treated as capital gain or loss.

Songa Offshore shareholders who are presently also holders of Shares or, following the consummation of the exchange offer, will become holders of Shares, may be taxed in Norway in connection with the receipt of future dividend income from Transocean (see “Material Tax Considerations—Norwegian Taxation—Dividend Distributions”) and the transfer of Shares (see “Material Tax Considerations—Norwegian Tax Considerations—Taxation of Gains on Disposals of Shares”), as well as interest earned and gains realized on the exchangeable bond.

Notwithstanding the description of certain aspects of taxation in Norway in “Material Tax Considerations—Norwegian Taxation,” shareholders may be liable to tax in other jurisdictions. In particular, shareholders with tax residency in Norway may be subject to an unlimited or limited tax liability in other jurisdictions, and shareholders that are subject to a limited tax liability in Norway may be liable to tax in the jurisdiction in which they are resident. A non-Norwegian holder will however generally not be subject to Norwegian income tax on gain recognized on the exchange of Songa Shares pursuant to the Offer unless the gain is connected with the non-Norwegian holder’s conduct of or participation in a business activity managed or exercised in or out of Norway.

For a more complete description of certain Norwegian tax consequences of the Combination, see “Material Tax Considerations—Norwegian Taxation.”

This summary is not intended to be a replacement for, nor should it be considered as, legal or tax advice. Shareholders of Songa Offshore are therefore strongly advised to consult their tax advisors regarding the tax consequences related to participation in the Offer and the holding and disposal of Shares. The specific tax situation of each shareholder can only be adequately addressed by individual tax advice.

Q:  WHAT PERCENTAGE OF TRANSOCEAN SHARES WILL FORMER HOLDERS OF SONGA SHARES OWN AFTER THE COMBINATION?

A:   The existing shareholders in Transocean will be diluted by approximately 27.9% as a consequence of the Offer and issuance of the Consideration Shares to the Songa Offshore shareholders, assuming the following:

Q:  IF THE OFFER IS COMPLETED, WILL THE CONSIDERATION SHARES AND THE EXCHANGEABLE BONDS ISSUED PURSUANT TO THE OFFER BE LISTED FOR TRADING?

A:   The Shares currently trade on the NYSE. Transocean will apply to list the Consideration Shares and the Exchangeable Bonds issued to Songa Offshore shareholders in the Offer on the NYSE. Consideration Shares and the Exchangeable Bonds will not be listed on any stock exchange in Norway. See “Risk Factors—Risks Related to the Shares” and “Risk Factors—Risks Related to the Exchangeable Bonds.”

Q:  DOES SONGA OFFSHORE SUPPORT THE OFFER AND THE COMBINATION?

A:   Yes. As a general rule, the board of directors of Songa Offshore is required to announce its view on the Offer in accordance with Section 6‑16 of the Norwegian Securities Trading Act no later than one week prior to the expiration of the Offer Period. As the Offer is initiated by Transocean in agreement with the board of directors of Songa Offshore, the Oslo Stock Exchange has instructed Songa Offshore to engage an independent advisor to issue a statement regarding the Offer pursuant to Section 6‑16 (4) of the Norwegian Securities Trading Act. Therefore Songa Offshore has engaged ABG Sundal Collier ASA to issue such independent statement on behalf of Songa Offshore. The independent statement is attached to this Prospectus as Annex D.

The board of directors of Songa Offshore has also issued a statement regarding the Offer; such statement is attached to this Prospectus as Annex E.

Q:  WHAT IS THE MARKET VALUE OF SONGA SHARES AS OF A RECENT DATE?

A:   The closing price of Songa Shares on the Oslo Stock Exchange on December 11, 2017 was NOK 58.00.

Q:  IS TRANSOCEAN’S FINANCIAL CONDITION RELEVANT TO A SONGA OFFSHORE SHAREHOLDER’S DECISION TO TENDER ITS SONGA SHARES IN THE OFFER?

A:   Yes. Songa Offshore shareholders will receive Consideration Shares, Exchangeable Bonds and cash pursuant to the Cash Election (if applicable) in exchange for tendering their Songa Shares in the Offer. Therefore, Songa Offshore shareholders should consider Transocean’s financial condition before deciding to become a Transocean shareholder and a bondholder by accepting the Offer. Songa Offshore shareholders should also consider the effect that the Combination of Transocean and Songa Offshore may have on

Transocean’s financial condition. In considering Transocean’s financial condition, Songa Offshore shareholders should review information relating to Transocean in this Prospectus, including the financial information incorporated by reference in this Prospectus, which also contain detailed business, financial and other information about Transocean.

Q:  WHERE CAN SONGA OFFSHORE SHAREHOLDERS FIND MORE INFORMATION ABOUT TRANSOCEAN AND SONGA OFFSHORE?

A:   Songa Offshore shareholders can find out information about Transocean and Songa Offshore from the sources described under “Where You Can Find More Information.” For certain information regarding Songa Offshore’s business and financial condition, see the sections of this Prospectus titled “Description of the Songa Offshore Business” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations of Songa Offshore.”

Q:  WHO CAN SONGA OFFSHORE SHAREHOLDERS CONTACT WITH ADDITIONAL QUESTIONS ABOUT THE OFFER?

A:   Songa Offshore shareholders can call the Settlement Agent with additional questions about the Offer:

Clarksons Platou Securities AS

Munkedamsveien 62c

N‑0270 Oslo

Norway

+47 22 01 63 00

Email: ecm.oslo@clarksons.com

SUMMARY

This summary highlights the material information in this Prospectus. To more fully understand the Combination and for a more complete description of the terms of the Offer and the other transactions contemplated by the Transaction Agreement, you should read carefully this entire document, including the exhibits, annexes, and documents incorporated by reference herein. For information on how to obtain these documents, see “Where You Can Find More Information.”

The Combination (page 111)

On August 13, 2017, Transocean entered into the Transaction Agreement with Songa Offshore, pursuant to which we are offering to acquire all of the Songa Shares through a voluntary tender offer in exchange for consideration per Songa Share consisting of (i) 0.35724 Consideration Shares issued by Transocean and (ii) USD 2.99726 principal amount of Exchangeable Bonds, to be issued by TINC and guaranteed by Transocean. As part of the Offer, each Songa Offshore shareholder may instead elect to receive the Cash Election in lieu of some or all of the Consideration Shares and Exchangeable Bonds such shareholder would otherwise be entitled to receive in the Offer. The aggregate amount of consideration paid to each Songa Offshore shareholder accepting the Offer shall be comprised, as near as possible, of 50% Consideration Shares and 50% Exchangeable Bonds, with any exercise by such shareholder of the Cash Election, if elected, being deducted first from the aggregate number of Exchangeable Bonds otherwise issuable to such shareholder and then from the aggregate number of Consideration Shares such shareholder would otherwise be entitled to receive in the Offer.

If the Offer is completed and we acquire Songa Shares representing 90% or more of the voting rights in Songa Offshore, we intend to initiate a compulsory acquisition (squeeze-out) of the remaining Songa Shares not owned by Transocean pursuant to article 36 of the Cyprus Takeover Bids Law (L.41(I)/2007), as amended, as soon as practicable following the completion of the Offer. A compulsory acquisition can be expected to be completed after 35 working days from completion of the Offer, provided that the required application is submitted to the Cyprus Securities and Exchange Commission immediately after completion and that the Cyprus Securities and Exchange Commission will make its decision on the application within 10 working days from its submission. It is expressly noted that this is an estimation only, as the process may be delayed due to several factors beyond the control of the Company. The Cyprus Securities and Exchange Commission is not subject to a time limit in deciding on the application, and no assurances can be given as to the exact duration of the compulsory acquisition process. See the section below “—Compulsory Acquisition” for further information.

Information About the Companies (see page 88)

Transocean Ltd.

Transocean Ltd. is the parent company of the Transocean Group of companies. Transocean was incorporated under the laws of Switzerland in 2008. Transocean has evolved to become a leading international provider of offshore contract drilling services for oil and gas wells. Transocean has approximately 4,930 employees worldwide.

Transocean’s registered and principal executive offices are located at Turmstrasse 30, CH‑6300 Zug, Switzerland and its telephone number at that location is +41 (41) 749 0500.

Transocean Inc.

Transocean Inc. is a corporation incorporated under the Companies Law of the Cayman Islands. The legal and commercial name is Transocean Inc. TINC was established in 1999 and registered in the Cayman Islands under the business registration number 89645. TINC’s principal executive offices are located at P.O. Box 10342, 70 Harbour Drive, 4th Floor, Grand Cayman, KY1‑1003, and its telephone number is +1 345 745 4500.

Songa Offshore SE

Songa Offshore SE, the parent company of the Songa Offshore group of companies, is a European public company organized under the laws of the Republic of Cyprus. Its predecessor company, Songa Offshore ASA, was incorporated in 2005 as a Norwegian public limited liability company and converted to an SE, by means of a merger between Songa Offshore ASA and Songa Offshore Cyprus Plc, in 2008. The principal business of the Songa Group is to own and operate drilling rigs to be used in exploration and production drilling. The Songa Group operates in the international oil-service industry within the offshore drilling sector, and owns a fleet of seven semi-submersible rigs. The Songa Group has approximately 934 employees worldwide.

Songa Offshore’s registered and principal executive offices are located at the Porto Bello building, Office 201, No 1 Siafi Street, 3042, Limassol, Cyprus, and its telephone number at that location is +357 2520 7700.

Risk Factors (see page 34)

The Combination, including the Offer, is subject to risks. You should carefully read and consider the risk factors in “Risk Factors” beginning on page 34.

Terms of the Offer (see page 88)

The summary below describes the principal terms and conditions of the Offer. Some of the terms and conditions described below are subject to important limitations and exceptions. You should carefully review “Terms of the Offer” and the Transaction Agreement, which contains a more detailed description of the terms and conditions to the Offer.

Transocean’s Reasons for the Combination (see page 123)

At a meeting held on August 11, 2017, after due consideration and consultation, the Transocean Board unanimously approved (i) the total consideration of NOK 47.50 per Songa Share and (ii) the Combination and the transactions contemplated thereby. In reaching its determination, the Transocean Board considered a number of factors in connection with its evaluation of the proposed transaction, including significant strategic opportunities and potential synergies, as generally supporting its decision to enter into the Transaction Agreement and proceed with the transactions contemplated thereby. See “The Combination—Background and Reasons for the Combination—Transocean’s Reasons for the Combination” for a discussion of the factors considered by the Transocean Board.

Songa Offshore’s Reasons for the Combination (see page 127)

The Songa Board (with the exception of Songa Offshore directors Mr. Mohn and Mr. Mikkelsen, who were excused from voting on whether to approve the Transaction Agreement) unanimously determined to enter into the Transaction Agreement and recommend that Songa Offshore’s shareholders accept the Offer.  In addition to consulting with Songa Offshore management and its financial and legal advisors, the Songa Board considered a number of factors when evaluating the transaction. See “The Combination—Background and Reasons for the Combination—Songa Offshore’s Reasons for the Combination” for a discussion of the factors considered by the Songa Board.

The Transaction Agreement (see page 154)

The terms and conditions of the Combination are contained in the Transaction Agreement, which is attached as Annex A to this Prospectus and incorporated into this Prospectus by reference. Transocean urges you to read the full text of the Transaction Agreement because it is the legal document between Transocean and Songa Offshore that governs the Combination.

Material Interests of Songa Offshore’s Board and Management in the Combination (see page 153)

Some of the members of the Songa Offshore board of directors (the “Songa Board”) and the Songa Offshore executive officers may have interests in the Combination that are different from, or in addition to, the interests of the Songa Offshore shareholders. These interests may include, but are not limited to, the treatment of restricted share units or other equity instruments owned by certain Songa Offshore executive officers under Songa Offshore’s long-term incentive plan (the “Songa Offshore Long-Term Incentive Plan”), or cash severance and other benefits under change in control arrangements. Additionally, Songa Offshore’s executive officers are expected to continue their employment with the combined company under the terms of their current employment agreements for an interim transitional period following completion of the Offer. These interests also include Transocean’s agreement to nominate the Perestroika Designee to the Transocean Board (subject to the election of Frederik W. Mohn, the Chairman of the Songa Board, as the Perestroika Designee at the Extraordinary General Meeting). As of August 14, 2017, members of the Songa Board and the Songa Offshore executive officers and their affiliates, excluding Perestroika AS (“Perestroika”), owned 361,160 Songa Shares in the aggregate, representing 0.3 percent of the issued Songa Shares. In addition, the Perestroika Designee is the sole owner of Perestroika, Songa Offshore’s largest shareholder. As of December 11, 2017, Perestroika held 59,489,590 Songa Shares and SONG07 convertible bonds convertible into 27,556,518 Songa Shares. Perestroika also holds approximately NOK 330 million principal amount of SONG04 bonds issued by Songa Offshore that will be purchased by Transocean at a price of 103.5% (plus accrued and unpaid interest) and a USD 50 million loan to Songa Offshore that will be purchased by Transocean at a price of 100% (plus accrued and unpaid interest), each in connection with the completion and settlement of the Offer. See “Terms of the Offer—Refinancing of Certain Songa Offshore Indebtedness.”

Comparison of Shareholders’ Rights (see page 265)

The rights of Transocean shareholders are governed by Swiss law and Transocean’s Articles of Association. In addition, Transocean is subject to the rules and regulations of the SEC and the NYSE that, among other things, regulate the solicitation of proxies and provide for additional shareholder rights requirements. The rights of Songa Offshore shareholders are governed by Cyprus law and Songa Offshore’s memorandum of association

and articles of association (“Songa’s Articles of Association”). Copies of Transocean’s Articles of Association and Songa’s Articles of Association are available, without charge, by following the instructions listed under “Where You Can Find More Information.”

As a result of the Combination, holders of Songa Shares will become shareholders of Transocean and their rights as shareholders will be governed by Swiss law and Transocean’s Articles of Association. There are many differences between the rights of Songa Offshore shareholders and those of Transocean shareholders.

Material Tax Considerations of the Combination (see page 295)

Tax matters are very complicated, and the tax consequences of the Offer to a particular holder will depend in part on such holder’s circumstances. Accordingly, holders of Songa Shares are urged to consult their own tax advisors for a full understanding of the tax consequences of the Offer to them, including the applicability of United States federal, state, local and foreign income and other tax laws.

Certain Material U.S. Income Tax Considerations

The exchange of Songa Shares for Consideration Shares and Exchangeable Bonds (and, to the extent shareholders elect the Cash Election, cash) pursuant to the Offer will be a taxable transaction for United States federal income tax purposes. U.S. holders of Songa Shares that participate in the Offer generally will recognize gain or loss equal to the difference, if any, between (i) the sum of (A) the fair market value of any Consideration Shares received in the Offer, determined in U.S. dollars, plus (B) the issue price, as determined for United States federal income tax purposes, of the Exchangeable Bonds received in the Offer, plus (C) the U.S. dollar amount of any cash received in Norwegian kroner in the Offer, plus (D) any cash received for any fractional Consideration Shares or Exchangeable Bonds and (ii) such U.S. holder’s adjusted tax basis in the Songa Shares exchanged. Provided that Songa Offshore is not treated as a passive foreign investment company for U.S. federal income tax purposes, any gain or loss recognized by a U.S. holder in connection with the Offer generally will be treated as capital gain or loss.

A non-U.S. holder will generally not be subject to United States federal income tax on gain recognized on the exchange of Songa Shares pursuant to the Offer unless the gain is “effectively connected” with the non-U.S. holder’s conduct of a trade or business in the United States or the non-U.S. holder is an individual present in the United States for 183 or more days in the taxable year of the exchange, and certain other requirements are met.

The foregoing is a brief summary of United States federal income tax consequences only and is qualified by the description of United States federal income tax considerations in “Material Tax Considerations—United States Taxation.”

Certain Material Norwegian Tax Considerations

The exchange of Songa Shares for Consideration Shares, Exchangeable Bonds (and, to the extent shareholders elect the Cash Election, cash) pursuant to the Offer will be a taxable transaction for Norwegian income tax purposes for individual shareholders, while for corporate shareholders the transaction is expected to normally be tax exempt under the Norwegian exemption method. Norwegian individual holders of Songa Shares that participate in the Offer generally will recognize gain or loss equal to the difference, if any, between (i) the sum of (A) the fair market value of any Consideration Shares received in the Offer, determined in NOK, plus (B) the

issue price, as determined for Norwegian income tax purposes, of the Exchangeable Bonds received in the Offer, plus (C) the amount of any cash received in Norwegian kroner received in the Offer and (ii) such individual Norwegian holder’s tax basis in the Songa Shares exchanged. Any gain or loss recognized by a Norwegian holder in connection with the Offer generally will be treated as capital gain or loss.

A non-Norwegian holder will generally not be subject to Norwegian income tax on gain recognized on the exchange of Songa Shares pursuant to the Offer unless the gain is connected with the non-Norwegian holder’s conduct of or participation in a business activity managed or exercised in or out of Norway.

The foregoing is a brief summary of Norwegian tax consequences only and is qualified by the description of Norwegian tax considerations in “Material Tax Considerations—Norwegian Taxation.”

Certain Material Swiss Tax Considerations

The exchange of Songa Shares for the Consideration is not subject to Swiss Federal withholding tax. The exchange of Songa Shares for the Consideration may be subject to Swiss securities transfer tax of up to 0.3 per cent. If such transfer tax will be due, it will be borne by Transocean.

The foregoing is a brief summary of Swiss tax consequences only and is qualified by the description of Swiss tax considerations in “Material Tax Considerations—Swiss Taxation.”

Terms of the Exchangeable Bonds

The following overview provides a summary of the main terms applicable to the Exchangeable Bonds. The full terms in respect of the Exchangeable Bonds are described in further detail under “Description of Transocean Exchangeable Bonds.”

SUMMARY SELECTED FINANCIAL DATA OF TRANSOCEAN

The selected financial data as of December 31, 2016 and 2015 and for each of the three years in the period ended December 31, 2016 have been derived from the audited consolidated financial statements included in “Item 8. Financial Statements and Supplementary Data” of Transocean’s annual report on Form 10‑K for the year ended December 31, 2016 (the “2016 Annual Report”). The selected financial data as of December 31, 2014, 2013 and 2012, and for each of the two years in the period ended December 31, 2013 have been derived from Transocean’s accounting records. The selected financial data as of September 30, 2017 and for the nine-month periods ended September 30, 2017 and 2016 have been derived from the unaudited condensed consolidated financial statements included in “Item 1. Financial Statements” of Transocean’s quarterly report on Form 10‑Q for the quarterly period ended September 30, 2017 (the “3Q17 Quarterly Report”).

The selected financial data should be read in conjunction with the sections titled “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations” and the audited consolidated financial statements and the notes thereto included under “Item 8. Financial Statements and Supplementary Data” of the 2016 Annual Report, “Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations” and the unaudited condensed consolidated financial statements and notes thereto included in “Item 1. Financial Statements” of the 3Q17 Quarterly Report and Transocean’s financial statements and related notes and other financial information incorporated by reference in this Prospectus.

SUMMARY SELECTED FINANCIAL DATA OF SONGA OFFSHORE

The following table sets forth selected historical consolidated financial information for Songa Offshore. The selected consolidated financial data of Songa Offshore as of and for the year ended December 31, 2016 has been derived from Songa Offshore’s audited consolidated financial statements as of and for the year ended December 31, 2016 (the “Songa Consolidated Financial Statements”) included elsewhere in this Prospectus, which have been prepared in accordance with International Financial Reporting Standards (the “IFRS”), as issued by the International Accounting Standards Board (the “IASB”). The selected consolidated financial data of Songa Offshore as of December 31, 2015 and for each of the two years in the period then ended has been derived from Songa Offshore’s unaudited consolidated financial statements included in this Prospectus, which have been prepared in accordance with IFRS, as issued by the IASB. The financial information presented of Songa Offshore as of December 31, 2014, 2013 and 2012, and for each of the two years in the period ended December 31, 2013 has been derived from the accounting records of Songa Offshore.

The financial information presented for Songa Offshore is not directly comparable to the financial data of Transocean because Transocean’s consolidated financial statements have been prepared in accordance with U.S. GAAP. The selected historical consolidated financial information of Songa Offshore as of September 30, 2017 and for the nine-month periods ended September 30, 2017 and 2016 have been derived from the unaudited interim condensed consolidated financial statements of Songa Offshore included elsewhere in this Prospectus, which have been prepared in accordance with IFRS, as issued by the IASB. The unaudited financial statements include all adjustments, consisting of normal recurring accruals, which Songa Offshore considers necessary for a fair presentation of the financial position and the results of operations for these periods. The selected historical consolidated financial information of Songa Offshore presented below is not necessarily indicative of the results of operations or financial condition that may be expected for any future period or date. The selected historical consolidated financial information presented below should be read in conjunction with Songa Offshore’s audited consolidated financial statements and unaudited interim condensed consolidated financial statements and notes thereto and “Management’s Discussion and Analysis of Financial Condition and Results of Operations of Songa Offshore” included in this Prospectus.