The defence chiefs of the three AUKUS partner nations have confirmed that the US Navy Virginia-class attack submarine USS Colorado will be the first boat assigned to Submarine Rotational Force-West (SRF-West) at HMAS Stirling in Western Australia, with her rotation beginning in late 2027.
The designation was announced jointly by US Secretary of War Pete Hegseth, Australian Deputy Prime Minister and Minister for Defence Richard Marles, and UK Secretary of State for Defence Wes Streeting.
SRF-West is projected to host one UK Astute-class and up to four US Virginia-class fast attack submarines at the Royal Australian Navy base. The Australian Submarine Agency said the boats will rotate through HMAS Stirling rather than be permanently based in Australia, consistent with the country's policy against foreign bases on its soil.
The announcement precedes a US submarine maintenance period at HMAS Stirling scheduled to begin later this week.
Agency Director-General Vice Admiral Jonathan Mead said the designation of Colorado, "signals the transition from planning to implementation."
The partners said the force is intended to advance Australia's readiness to take ownership of, operate, maintain and regulate a nuclear-powered, conventionally armed submarine capability, which Australia plans to have from the early 2030s. Australian sailors are to gain at-sea experience aboard the US and UK boats, while Australian maintenance personnel support them ashore.
The US Navy established Naval Support Activity Stirling on May 30 to provide housing, healthcare, and other services for US personnel and families assigned to SRF-West. It re-established Submarine Squadron Three to operate from the base in June.
Colorado was commissioned on March 17, 2018, as the 15th Virginia-class submarine and the fifth Block III boat of the class. Assigned to Submarine Squadron Seven, the submarine completed her period of maintenance at Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility 29 days ahead of schedule, then returned to the fleet in June.
