IN Brief:
- USS Colorado has been designated the first US submarine for SRF-West in late 2027.
- HMAS Stirling is planned to accommodate rotations by up to four US submarines and one UK submarine.
- A further US submarine maintenance period in Western Australia is due to begin later this week.
The Australian Department of Defence, together with the United States and United Kingdom, has designated USS Colorado (SSN 788) as the first Virginia-class submarine assigned to Submarine Rotational Force-West (SRF-West) from late 2027. The designation identifies a specific US Navy boat for the forthcoming rotation at HMAS Stirling in Western Australia. It does not represent an arrival at the base, an Australian submarine purchase or a permanent transfer of home port.
The three governments intend the rotational force to bring nuclear-powered attack submarines into HMAS Stirling for periodic operations and sustainment activity. The projected maximum is up to four US fast-attack submarines and one UK submarine rotating through the installation. The force is part of AUKUS Pillar I, through which Australia plans to develop a sovereign fleet of conventionally armed, nuclear-powered submarines and the personnel and facilities needed to support them.
The announcement comes ahead of another United States submarine maintenance period expected to begin in Western Australia later this week. That work will build on earlier maintenance activity involving USS Vermont, during which Australian personnel supported work on a visiting Virginia-class boat. The maintenance periods provide opportunities to test processes and workforce arrangements before the recurring rotations begin, although the details of the forthcoming work package have not been made public.
Supporting a visiting nuclear-powered vessel requires more than suitable alongside berths. Maintenance facilities need controlled equipment, traceable spares, trained tradespeople, engineering supervision and documented work procedures, while any activities affecting nuclear propulsion require additional specialist safety and regulatory controls. Australia has experience sustaining its conventionally powered Collins-class submarines, but procedures for visiting allied nuclear-powered boats must be practised under the authorities and technical standards that apply to those vessels.
HMAS Stirling, on Garden Island near Perth, is therefore undergoing a major infrastructure programme. Australia has committed up to A$8 billion to expand the base, with about 3,000 direct Australian jobs associated with the work according to the government’s June 2026 programme update. The planned investment covers the support environment for visiting allied submarines while also creating facilities intended to serve Australia’s future fleet. The financial figure refers to the broader Stirling development rather than a contract awarded with the selection of Colorado.
Support organisations are being established alongside the physical works at HMAS Stirling. The US Navy has made preparations for Submarine Squadron 3, a maintenance activity in Western Australia and Naval Support Activity Stirling, covering operational oversight, maintenance coordination and support for US personnel and contractors. Australian and British participants will operate within arrangements that distinguish a boat’s operational command from responsibility for authorising, undertaking and accepting maintenance work.
Australian Defence Force members and industry personnel are expected to gain experience by participating in support and maintenance work on allied submarines. Learning the maintenance regime involves controlled technical instructions, inspection evidence, configuration records and assurance that work has been performed by suitably qualified personnel. Skills acquired on visiting vessels should assist Australia in creating its own sustainment workforce, although separate approvals and infrastructure will still be required for Australian-operated boats.
The designated submarine is an existing US Navy Virginia-class nuclear-powered fast-attack vessel. Its participation is a force-posture and industrial-readiness development; it does not itself increase the number of submarines owned by Australia. The three partners have stated that rotations will operate at Australia’s invitation and under applicable agreements, including the US–Australia Force Posture Agreement, while observing their respective nuclear non-proliferation commitments.
The planned late-2027 start leaves further maintenance demonstrations, infrastructure construction and personnel preparation to be completed before rotations become routine. Under the broader AUKUS pathway, Australia plans to acquire Virginia-class submarines from the United States in the early 2030s before moving towards SSN-AUKUS construction. That longer programme makes the near-term development of nuclear-submarine sustainment skills and shore facilities a practical requirement, although the rotational force and Australia’s future owned fleet remain separate undertakings.
The coming sustainment trials must also establish how technical records and responsibility pass between allied personnel. Repair work may be physically performed at the Australian site while engineering approval, component traceability and configuration control involve US or UK authorities. Those interfaces are as important as workshops and lifting equipment because nuclear-submarine maintenance requires unambiguous accountability and a documented route for accepting each completed task.
USS Colorado gives the three governments a named vessel around which to coordinate the first rotation. The forthcoming maintenance period and subsequent work at HMAS Stirling will provide evidence of how efficiently personnel, facilities and technical authorities can support allied submarines before SRF-West begins in late 2027.
