RIG: Company disclosure

Item 7.01 Regulation FD Disclosure. ​ Transocean Ltd. (NYSE: RIG) (“Transocean”) today announced contract awards for two of its harsh environment semisubmersibles. In aggregate, the fixtures represent approximately $185 million in firm contract backlog. ​ The Transocean Norge was awarded a five-well contract with Harbour Energy in Norway. The estimated 300 days of work is expected to commence in the first quarter of 2028 in direct continuation of the rig’s current program and contribute approximately $149 million in backlog, excluding mobilization and additional services. The contract also includes three one-well options. ​ The Transocean Equinox was awarded a two-well contract with Santos in Australia. The estimated 90 days of work is expected to commence in the second quarter of 2027 and contribute approximately $36 million in backlog, excluding mobilization and additional services. The contract also includes five one-well options. ​ A copy of the press release announcing the fixtures 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 $185 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: June 16, 2026 By: /s/ Debra Kupferman ​ ​ Debra Kupferman ​ ​ Authorized Person ​ ​