US submarine squadron established in WA

The US Navy has reestablished Submarine Squadron 3 (CSS-3), which will operate out of HMAS Stirling in Western Australia.

FILE PHOTO (October 2025): Virginia-class fast-attack submarine USS Vermont (SSN 792) arrives at HMAS Stirling in Western Australia for a scheduled Submarine Maintenance Period (SMP). Photo by Able Seaman Jaxsen Shinners.

Previously operated out of Pearl Harbor, Hawaii, and decommissioned in February 2012, the reestablishment of CSS-3 in WA is a key milestone in support of the Australia, United Kingdom, United States (AUKUS) trilateral security partnership.

CSS-3’s personnel will integrate with their Royal Australian Navy counterparts to lay the groundwork for maintenance, logistics and operational support for all US and UK submarines rotating through HMAS Stirling.

CSS-3’s reactivation is a critical step toward establishing (Submarine Rotational Force) SRF-West, a key AUKUS Pillar I milestone, allowing US and UK nuclear-powered fast-attack submarines (SSNs) to conduct rotations from the Royal Australian Navy base HMAS Stirling starting in 2027.

Commander, Submarine Force, US Pacific Fleet, Rear Admiral Chris Cavanaugh  said that the reactivated squadron would enhance operations in the theatre.

“Adding an additional forward-positioned submarine squadron in the Indo-Pacific enhances our presence, agility, and responsiveness across a range of operations,” Rear Admiral Cavanaugh said.

“CSS-3 enables our submarines and crews to respond rapidly in support of the US joint-force mission of regional deterrence.”

Director of Submarine Programs Vice Admiral Rob Gaucher said establishing Naval Support Activity (NSA) Stirling and reestablishing CSS-3 laid 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,” Vice Admiral Gaucher said.

“That not only supports readiness, but it also reduces the burden on US shipyards and increases our fast-attack submarine force’s readiness while preparing Australia to maintain their own SSNs.”

Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility (PHNSY & IMF) will also stand up a maintenance and logistics detachment in Western Australia in mid-2026.

This detachment will oversee and execute intermediate-level maintenance on US submarines assigned to SRF-West and will continue to train the Australian workforce.

Deputy Program Acquisition Executive, Industrial Operations for Public Shipyards, Rear Admiral Scott Brown said that, to date, approximately 20 Australian civilian maintainers and 25 Royal Australian Navy divers and Fleet Support Unit officers and sailors had completed their training at Pearl Harbor Naval Shipyard, with more than 230 others currently under instruction in Hawaii.

“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,” Rear Admiral Brown said

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