The US Navy has reactivated Submarine Squadron 3 (CSS-3) to support the Submarine Rotational Force-West (SRF-West) at HMAS Stirling, Western Australia, according to a report published by DVIDS on 10 June 2026.
Rear Admiral Chris Cavanaugh, commander, Submarine Force, US Pacific Fleet, authorised the return of the squadron, which was previously based at Pearl Harbor, Hawaii, until its decommissioning in February 2012.
The decision follows the trilateral Joint Statement issued by Australia, the UK and the US on 30 May.
That statement confirmed progress towards meeting key milestones for SRF-West under the Australia–UK–US (AUKUS) security partnership.
Submarine Squadron 3 will now operate out of HMAS Stirling, where its personnel will work with Royal Australian Navy counterparts.
Their integration aims to establish the necessary frameworks for maintenance, logistics, and operational support for US and UK submarines that will rotate through the Australian base.
According to DVID, the reactivation of CSS-3 is a “critical step” towards instituting SRF-West, which is identified as a principal milestone under Pillar I of AUKUS.
Through SRF-West, the US and UK intend to rotate nuclear-powered fast-attack submarines (SSNs) from HMAS Stirling beginning in 2027.
Rear Admiral Chris Cavanaugh said: “Adding an additional forward-positioned submarine squadron in the Indo-Pacific enhances our presence, agility, and responsiveness across a range of operations.
"CSS-3 enables our submarines and crews to respond rapidly in support of the US joint force mission of regional deterrence.”
This latest move follows the establishment of Naval Support Activity (NSA) Stirling by Navy Region Japan.
NSA Stirling will deliver support services and programmes to US personnel, contractors, and families posted to SRF-West.
Submarine programmes director Vice Admiral Rob Gaucher said: “Establishing NSA Stirling and reestablishing CSS-3 lays the foundation for SRF-West and, ultimately, Australia’s sovereign conventionally armed, nuclear-powered submarine fleet.
"With SRF-West, we have submarines rotating through a critical region with an organic, predominately Australian, maintenance workforce keeping those boats fit to fight.”
In mid-2026, a detachment from Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility (PHNSY & IMF) is expected to commence in Western Australia.
This unit will provide and oversee intermediate-level maintenance on US submarines assigned to SRF-West, while continuing to instruct the Australian workforce.
According to Vice Admiral Scott Brown, deputy program acquisition executive, industrial operations for Public Shipyards, approximately 20 Australian civilian maintainers and 25 Royal Australian Navy divers and Fleet Support Unit personnel have completed their training at Pearl Harbor Naval Shipyard, with over 230 others currently undertaking instruction in Hawaii.
Brown said: “The Pearl Harbor team is working to build Australia’s sovereign SSN maintenance capability that will keep our submarines ready for tasking in Western Australia.
"Right now, Australian maintainers are learning by doing aboard in-service SSNs which provides additional work hours to the shipyard and helps us get boats back to the fleet on time.”
