RIG: Company disclosure

Item 7.01 Regulation FD Disclosure. ​ Transocean Ltd. (NYSE: RIG) (“Transocean”) today announced that the Deepwater Conqueror was awarded a two-well contract for work in Equatorial Guinea with an undisclosed operator. The estimated 170-day campaign is expected to commence in 2027 in direct continuation of the rig’s current contract in the U.S Gulf and contribute approximately $80 million in backlog, excluding additional services and compensation for mobilization and demobilization. ​ 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 $80 Million Contract For Ultra-Deepwater Drillship 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: September 15, 2026 By: /s/ Debra Kupferman ​ ​ Debra Kupferman ​ ​ Authorized Person ​ ​