U.S. Navy Revives Submarine Squadron 3 in Australia to Extend Allied Undersea Reach Across Indo-Pacific.

The U.S. Navy has reactivated Submarine Squadron 3 in Western Australia, DVIDS reported on June 10, 2026, creating a forward command element for AUKUS submarine operations at HMAS Stirling. The move strengthens allied undersea deterrence in the Indo-Pacific by giving U.S. and future UK attack submarines a more resilient support base closer to key maritime corridors.

CSS-3 will help coordinate maintenance, logistics, and operational support for Submarine Rotational Force-West before regular nuclear-powered submarine rotations begin in 2027. Its return turns AUKUS from a future acquisition plan into a working undersea warfare network that builds Australian expertise while increasing allied readiness, survivability, and reach.

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The U.S. Navy has reactivated Submarine Squadron 3 at HMAS Stirling in Western Australia, establishing a forward command structure that will support AUKUS submarine rotations and strengthen allied undersea deterrence across the Indo-Pacific (Picture Source: U.S. Navy)

On June 10, 2026, the Defense Visual Information Distribution Service reported that the U.S. Navy had reestablished Submarine Squadron 3, or CSS-3, to support Submarine Rotational Force-West at HMAS Stirling in Western Australia. The move marks a new phase in the Australia, United Kingdom, United States AUKUS trilateral security partnership, turning the undersea component of the agreement into a forward naval command structure on Australian territory. By restoring a squadron that previously operated from Pearl Harbor, Hawaii, and was decommissioned in February 2012, the U.S. Navy is reinforcing its Indo-Pacific submarine posture while helping Australia prepare the command, logistics, maintenance, and workforce foundations required for a future sovereign conventionally armed, nuclear-powered submarine fleet.

The reactivation of CSS-3 should be read as more than the return of a former U.S. submarine squadron. It represents one of the first visible layers of a forward undersea command architecture designed to connect U.S. Navy nuclear-powered attack submarine operations, Royal Australian Navy support structures, and future UK submarine rotations into a single operational framework in the eastern Indian Ocean. The last incarnation of CSS-3 ended on February 2, 2012, when the Pearl Harbor-based Commander, Submarine Squadron 3 was disestablished during a ceremony aboard the Los Angeles-class nuclear-powered attack submarine USS Greeneville at Joint Base Pearl Harbor-Hickam.

At that time, the squadron’s attack submarines were reassigned across the Pacific submarine force: USS Jacksonville, USS Key West, and USS North Carolina moved to Submarine Squadron 1, while USS Louisville and USS Olympia were assigned to Submarine Squadron 7, and USS Chicago was assigned to Submarine Squadron 15 in Apra Harbor, Guam. This historical background gives the 2026 reactivation added operational meaning, as CSS-3 returns not as a traditional Pearl Harbor-based submarine squadron but as a forward-positioned command element at the center of AUKUS implementation in Australia.

Submarine Rotational Force-West is the core of this architecture. From 2027, U.S. and UK nuclear-powered fast-attack submarines are expected to conduct rotations from HMAS Stirling, allowing allied SSNs to operate from a forward location with access to local maintenance, logistics support, pier services, command coordination, and trained Australian personnel. This model gives the United States and its partners a more flexible undersea posture without converting the base into a permanent foreign homeport. It also reduces transit distances from distant facilities, improves operational availability, and gives allied commanders greater flexibility for anti-submarine warfare, anti-surface warfare, intelligence collection, maritime surveillance, sea-denial missions, special operations support, and protection of sea lines of communication.

CSS-3 will provide the command and coordination layer needed to make these rotations credible and sustainable. Its personnel will integrate with Royal Australian Navy counterparts to prepare maintenance, logistics, and operational support for rotational U.S. and UK submarines at HMAS Stirling. This integration will expose Australian sailors, civilian maintainers, divers, and Fleet Support Unit personnel to the standards that govern nuclear-powered submarine operations, including intermediate-level maintenance, diving support, hull services, port safety, logistics planning, emergency response procedures, and the nuclear stewardship culture required for SSN sustainment. For Australia, this is a direct path toward building national expertise; for the United States, it creates a stronger forward support network for its fast-attack submarine force.

The geostrategic value of HMAS Stirling gives the decision wider military relevance. Located on Australia’s west coast near Perth, the base provides access to the eastern Indian Ocean, the approaches to Southeast Asia, and onward routes toward the Western Pacific. This position gives allied SSNs the ability to operate across a broad maritime arc without relying only on Guam, Hawaii, Japan, or U.S. West Coast facilities. In a region shaped by long-range missiles, expanding submarine fleets, seabed infrastructure vulnerabilities, and competition for control of maritime corridors, a distributed submarine support network gives the United States and Australia greater resilience and complicates the calculations of any potential adversary seeking to track, contain, or disrupt allied undersea operations.

The establishment of Naval Support Activity Stirling adds the shore infrastructure needed to support this operational concept. NSA Stirling will provide services and programs for U.S. military personnel, civilians, contractors, and their families assigned to SRF-West, creating the administrative and quality-of-life framework required for a durable rotational presence. In parallel, Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility is expected to stand up a maintenance and logistics detachment in Western Australia in mid-2026. This detachment will oversee and execute intermediate-level maintenance on U.S. submarines assigned to SRF-West while continuing to train the Australian workforce. Approximately 20 Australian civilian maintainers and 25 Royal Australian Navy divers and Fleet Support Unit personnel have already completed training at Pearl Harbor, with more than 230 additional Australians under instruction in Hawaii.

For Washington, the arrangement strengthens forward readiness by expanding repair options, improving theater responsiveness, and easing pressure on U.S. shipyards. For Canberra, it accelerates the development of a sovereign SSN support base and confirms Australia’s role as one of America’s most trusted undersea warfare partners. The AUKUS model is not limited to the future acquisition of Virginia-class submarines and the later development of SSN-AUKUS; it is creating an operational ecosystem in which Australian personnel learn aboard in-service submarines, support visiting allied SSNs, and gradually acquire the skills needed to operate, maintain, and regulate their own nuclear-powered submarine capability. This gives Australia a more active role in allied deterrence while reinforcing its position as a key maritime power in the Indo-Pacific.

The return of Submarine Squadron 3 marks a concrete shift in the implementation of AUKUS Pillar I. By linking CSS-3, NSA Stirling, Pearl Harbor Naval Shipyard support, and Royal Australian Navy workforce training, the United States and Australia are building the operational foundation for SRF-West before the first regular SSN rotations begin in 2027. This strengthens allied undersea readiness, supports Australia’s sovereign submarine ambitions, and places HMAS Stirling at the center of a long-term deterrence architecture across the Indo-Pacific.

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Written by Teoman S. Nicanci – Defense Analyst, Army Recognition Group

Teoman S. Nicanci holds degrees in Political Science, Comparative and International Politics, and International Relations and Diplomacy from leading Belgian universities, with research focused on Russian strategic behavior, defense technology, and modern warfare. He is a defense analyst at Army Recognition, specializing in the global defense industry, military armament, and emerging defense technologies.