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Your Vote Counts! TRANSOCEAN LTD. TURMSTRASSE 30 CH-6312 STEINHAUSEN SWITZERLAND TRANSOCEAN LTD. 2023 Annual General Meeting Vote by 11:59 PM EDT May 10, 2023 / 5:59 AM Swiss Time on May 11, 2023 You invested in TRANSOCEAN LTD. and it’s time to vote! You have the right to vote on proposals being presented at the Annual General Meeting. This is an important notice regarding the availability of proxy material for the shareholder meeting to be held on May 11, 2023. Get informed before you vote View the Combined Document online OR you can receive a free paper or email copy of the material(s) by requesting prior to April 24, 2023. If you would like to request a copy of the material(s) for this and/or future shareholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. Smartphone users Point your camera here and vote without entering a control number V1.1 For complete information and to vote, visit www.ProxyVote.com Control # V05830-P88650 Meeting Date May 11, 2023 6:30 p.m. Swiss Time Parkhotel Zug Industriestrasse 14 6304 Zug, Switzerland

THIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming shareholder meeting. Please follow the instructions on the reverse side to vote on these important matters. Vote at www.ProxyVote.com Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Delivery Settings”. Voting Items Board Recommends V05831-P88650 2A. Approval of the 2022 Annual Report, Including the Audited Consolidated Financial Statements of Transocean Ltd. for Fiscal Year 2022 and the Audited Statutory Financial Statements of Transocean Ltd. for Fiscal Year 2022 2B. Advisory Vote to Approve Swiss Statutory Compensation Report for Fiscal Year 2022 3. Discharge of the Members of the Board of Directors and the Executive Management Team from Liability for Activities During Fiscal Year 2022 4. Appropriation of the Accumulated Loss for Fiscal Year 2022 5. Approval of Shares Authorized for Issuance 6. Election of 11 Directors (6A – 6K), Each for a Term Extending Until Completion of the Next Annual General Meeting 7. Reelection of Chadwick C. Deaton as the Chair of the Board of Directors for a Term Extending Until Completion of the Next Annual General Meeting 8. Reelection of the Members of the Compensation Committee (8A-8C), Each for a Term Extending Until Completion of the Next Annual General Meeting 8A. Glyn A. Barker 8B. Vanessa C.L. Chang 8C. Samuel J. Merksamer 9. Reelection of Schweiger Advokatur / Notariat as the Independent Proxy for a Term Extending Until Completion of the Next Annual General Meeting 10. Appointment of Ernst & Young LLP as the Company’s Independent Registered Public Accounting Firm for Fiscal Year 2023 and Reelection of Ernst & Young Ltd, Zurich, as the Company’s Auditor for a Further One-Year Term 11. Advisory Vote to Approve Named Executive Officer Compensation for Fiscal Year 2023 12. Advisory Vote to Approve Frequency of Named Executive Officer Compensation Vote 13. Prospective Vote on the Maximum Compensation of (A) the Board of Directors and (B) the Executive Management Team 14. Approval of (A) Amendment and Restatement of Transocean Ltd. 2015 Long-Term Incentive Plan and (B) Capital Authorization for Share-Based Incentive Plans 13A Ratification of the Maximum Aggregate Amount of Compensation of the Board of Directors for the Period Between the 2023 Annual General Meeting and the 2024 Annual General Meeting 14A Approval of Amendment and Restatement of Transocean Ltd. 2015 Long-Term Incentive Plan 13B Ratification of the Maximum Aggregate Amount of Compensation of the Executive Management Team for Fiscal Year 2024 14B Approval of Capital Authorization for Share-Based Incentive Plans 15. Approval of Amendments to Articles of Association to Reflect New Swiss Corporate Law and Make Certain Related Changes For For For For For For For For For For For For For For For For For For For For For For For For For For For 6A. Glyn A. Barker 6B. Vanessa C.L. Chang 6C. Frederico F. Curado 6D. Chadwick C. Deaton 6E. Domenic J. “Nick” Dell’Osso, Jr. 6F. Vincent J. Intrieri 6G. Samuel J. Merksamer 6I. Edward R. Muller 6J. Margareth Øvrum 6K. Jeremy D. Thigpen 6H. Frederik W. Mohn For Every Year 2. Approval of (A) the 2022 Annual Report, Including the Audited Consolidated Financial Statements of Transocean Ltd. for Fiscal Year 2022 and the Audited Statutory Financial Statements of Transocean Ltd. for Fiscal Year 2022 and (B) the Swiss Statutory Compensation Report for Fiscal Year 2022 1. Reallocation of CHF 9.5 Billion of Free Capital Reserves from Capital Contribution to Statutory Capital Reserves from Capital Contribution For