RIG: Company disclosure

Item 7.01 Regulation FD Disclosure. ​ Transocean Ltd. announced contract awards for two of its ultra-deepwater drillships in the U.S. Gulf. In aggregate, the fixtures represent approximately $550 million in firm contract backlog. ​ The Deepwater Proteus was awarded a ten-well contract with an undisclosed operator in the U.S. Gulf. The estimated 700-day campaign is expected to contribute approximately $325 million in backlog and commence in the first quarter of 2027 in direct continuation of the rig’s current U.S. Gulf contract. ​ The Deepwater Conqueror was awarded a five-well contract with an undisclosed operator in the U.S. Gulf. The estimated 450 days of work is expected to contribute approximately $225 million in backlog, excluding mobilization fees, and commence in the third quarter of 2027 in direct continuation of the rig’s program in Equatorial Guinea. ​ A copy of the press release announcing the fixture referred to above is attached hereto and incorporated herein by reference as Exhibit 99.1 . ​ Item 9.01 Financial Statements and Exhibits. ​ (d) Exhibits. ​ ​ ​ ​ Exhibit No . ​ ​ ​ Description ​ ​ ​ 99.1 ​ Transocean Ltd. Announces Contract Awards Totaling $550 Million 101 ​ Interactive data files pursuant to Rule 405 of Regulation S-T formatted in Inline Extensible Business Reporting Language 104 ​ Cover Page Interactive Data File (formatted as inline XBRL). ​ SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. ​ TRANSOCEAN LTD. ​ ​ ​ ​ Date: October 9, 2026 By: /s/ Debra Kupferman ​ ​ Debra Kupferman ​ ​ Authorized Person ​