The new Submarine Squadron 3, known as CSS-3, will operate from HMAS Stirling in Western Australia. The move follows a trilateral Joint Statement on May 30 confirming that key milestones continue to be met for SRF-West in support of the Australia, United Kingdom and United States partnership.
CSS-3 personnel will integrate with Royal Australian Navy counterparts at HMAS Stirling. Their work will help establish maintenance, logistics and operational support for rotational U.S. and U.K. submarines at the base.
The reactivation of CSS-3 is a critical step toward establishing SRF-West as an AUKUS Pillar I milestone. Under SRF-West, U.S. and U.K. nuclear-powered fast-attack submarines will begin rotations from HMAS Stirling in 2027.
Cavanaugh said the reactivated squadron will strengthen operations in the region. “Adding an additional forward-positioned submarine squadron in the Indo-Pacific enhances our presence, agility, and responsiveness across a range of operations,” said Cavanaugh.
“CSS-3 enables our submarines and crews to respond rapidly in support of the U.S. joint force mission of regional deterrence,” Cavanaugh said. The U.S. Navy said the squadron will support the operational framework needed for rotational submarine activity in Western Australia.
CSS-3’s reestablishment follows Navy Region Japan’s stand-up of Naval Support Activity Stirling. NSA Stirling will provide support services and programs for U.S. service members, civilian personnel, contractors and families assigned to SRF-West.
“Establishing NSA Stirling and reestablishing CSS-3 lays the foundation for SRF-West and, ultimately, Australia’s sovereign conventionally armed, nuclear-powered submarine fleet,” said Director of Submarine Programs Vice Adm. Rob Gaucher. “With SRF-West, we have submarines rotating through a critical region with an organic, predominately Australian, maintenance workforce keeping those boats fit to fight.”
“That not only supports readiness, but it also reduces the burden on the U.S. shipyards and increases our fast-attack submarine force’s readiness while preparing Australia to maintain their own SSNs,” Gaucher said. The Navy said the structure is intended to support both current submarine rotations and Australia’s future nuclear-powered submarine capability.
Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility will also establish a maintenance and logistics detachment in Western Australia in mid-2026. The detachment will oversee and conduct intermediate-level maintenance on U.S. submarines assigned to SRF-West and continue training the Australian workforce.
“To date, approximately 20 Australian civilian maintainers and 25 Royal Australian Navy divers and Fleet Support Unit officers and sailors have completed their training at Pearl Harbor Naval Shipyard, and we have more than 230 others currently under instruction in Hawaii,” said Rear Adm. Scott Brown, deputy Program Acquisition Executive, Industrial Operations for Public Shipyards.
“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,” Brown said. “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.”
