RIG: Company disclosure

Item 7.01 Regulation FD Disclosure. ​ Transocean Ltd. (NYSE: RIG) (“Transocean”) today announced a two-year binding Letter of Award for the Dhirubhai Deepwater KG2 with ONGC in India. The campaign is expected to commence in the first quarter of 2027 and contribute approximately $300 million in contract value, inclusive of additional services and mobilization fees. The contract includes two years of priced options that, if fully exercised, would result in the drillship working in India into early 2031. ​ 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 $300 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: August 20, 2026 By: /s/ Debra Kupferman ​ ​ Debra Kupferman ​ ​ Authorized Person ​ ​