Australia confirms enduring access for US Virginia-class submarines at HMAS Stirling naval base under AUKUS.

On August 4, 2026, Australia’s Chief of the Defence Force, Admiral Mark Hammond, formally confirmed that U.S. Navy attack submarines will retain enduring access to the HMAS Stirling naval base in Western Australia under Submarine Rotational Force-West. The declaration resolves operational ambiguity following earlier government statements suggesting a strict five-year limit on rotational deployments. Establishing long-term access allows U.S. and allied naval commanders to permanently integrate Western Australia into Indo-Pacific deployment, maintenance, and logistics planning rather than treating the facility as a temporary transition point.

Submarine Rotational Force-West at HMAS Stirling is designed to support up to four U.S. Virginia-class and one British Astute-class nuclear-powered submarine, supported by an A$8 billion base expansion and 2,300 U.S. defense personnel. The enduring posture framework establishes nuclear-certified maintenance, logistics, and operational infrastructure capable of sustaining allied SSN deployments from the Indian Ocean through subsequent decades.

Related topic: Why Australia dropped new Virginia-class submarines for three used US Navy units in new AUKUS plan

Enduring access to a naval base means submarines can use that base whenever needed to operate, resupply, undergo maintenance, and remain ready for missions over the long term without relying on temporary visits. (Picture source: Australian MoD)

On August 4, 2026, Australia's Chief of the Defence Force, Admiral Mark Hammond, confirmed during a press conference that U.S. nuclear-powered attack submarines will retain "enduring access" to HMAS Stirling naval base under Submarine Rotational Force-West, resolving uncertainty over whether the American presence would terminate after the initial five-year period beginning in 2027. The clarification followed Defence Industry Minister Pat Conroy's statement that SRF-West was a five-year commitment that would end once Australia became "sovereign ready" and began receiving its own Virginia-class submarines in the early 2030s. Defence Minister Richard Marles then stated that SRF-West was intended to remain an enduring element of U.S. force posture in Australia, and Hammond subsequently repeated that position publicly.

The difference is operational rather than semantic: a five-year rotation ending in 2032 would make HMAS Stirling a transition mechanism for preparing Australia to receive its first SSNs, whereas enduring access allows U.S. submarine commanders to incorporate Western Australia into their deployment planning after Australian Virginia-class boats enter service. This changes the purpose of the infrastructure now being built at Stirling: submarine berths, maintenance spaces, logistics facilities, command organizations, communications, accommodation and nuclear-support infrastructure are not being configured solely for a 2027-2032 transition period, but for a support architecture that can remain available for recurring U.S., British and Australian submarine activity over subsequent decades.

The policy dispute exposed an important distinction between rotational deployment and operational permanence. Conroy said that individual U.S. submarines would remain at Stirling only for limited periods each year and compared SRF-West with the U.S. Marine Rotational Force-Darwin, arguing that neither arrangement constituted permanent foreign basing. That description remains compatible with enduring access because nuclear-powered attack submarines do not need to spend most of their deployment alongside a pier to obtain the military benefits of forward basing. Virginia-class SSNs rotate between patrols, crew support, maintenance periods and longer depot availabilities, and submarines that are not undergoing major repairs can spend up to 80% of their operational life at sea.

The practical issue is therefore not whether a specific Virginia-class boat remains permanently berthed at Garden Island, but whether U.S. submarines can return repeatedly to a predictable Australian support location for maintenance, stores, personnel support and operational regeneration. The Pentagon sought clarification for roughly 48 hours after Conroy's original comments because a fixed 2032 termination date would have affected long-term decisions on personnel assignments, maintenance detachments, command structures and investment. Under the revised interpretation, submarines continue to rotate, but the access arrangement and the shore infrastructure that make those rotations possible remain available. This gives Washington a persistent submarine-support option without transforming HMAS Stirling into a U.S.-owned or U.S.-controlled naval installation, as the base already has the scale and specialization required to serve as the foundation for that arrangement.

The base was commissioned on July 28, 1978, after the construction of the Garden Island facilities began in the early 1970s as part of Australia's Two-Ocean Policy. The 4.3 km causeway connecting Garden Island to the mainland was completed in June 1973, the first submarine assigned permanently to Stirling was HMAS Oxley in 1987, and the headquarters of the Australian Submarine Squadron moved there in 1994. The naval base now supports all six Collins-class submarines, four Anzac-class frigates, the Supply-class replenishment ship HMAS Stalwart and other fleet units. Its existing shore population includes roughly 2,300 service personnel, 600 Defence civilians and 500 contractors, before the full SRF-West personnel buildup. Facilities already include submarine wharves, repair and refit capacity, a ship-lift, fuel storage, medical facilities, accommodation and helicopter support, as well as the only Submarine Escape Training Facility in the Southern Hemisphere, one of six worldwide.

Garden Island covers 13 km², measures 10 km in length and 1.5 km in width, and the naval establishment occupies 28% of the island. This existing concentration of submarine infrastructure makes Stirling materially different from establishing an SSN support location at an undeveloped port because SRF-West is adding nuclear-qualified facilities and allied support functions to a mature submarine base rather than constructing an entirely new naval complex. The planned force structure gives a clear throughput requirement. From 2027, SRF-West is intended to support one British Astute-class attack submarine and up to four U.S. Navy Virginia-class SSNs on rotation, meaning the support system must be capable of accommodating a maximum planned rotational force of five allied SSNs while simultaneously supporting Australia's existing submarine force and preparing for Australian-owned Virginia-class boats. 

Canberra plans to spend up to A$8 billion on infrastructure and logistics at HMAS Stirling, while Western Australian authorities said on August 7, 2026 that more than A$6 billion of construction activity was already underway there. The program includes expanded berthing, nuclear-certified maintenance infrastructure, secure logistics areas and a Controlled Industrial Facility for submarine work requiring nuclear stewardship controls. A further A$12 billion is allocated to the Henderson Defence Precinct in Western Australia, where depot-level maintenance and contingency docking are intended to support future submarine operations, while A$3.9 billion is assigned to the future submarine construction yard in South Australia. Personnel requirements are similarly large. 

Plans call for 2,300 American personnel in Western Australia to support the enduring submarine presence, alongside British personnel and the expanding Australian workforce. Naval Support Activity Stirling provides the administrative structure for U.S. military personnel, civilians, contractors and their families, while a Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility detachment is being established to provide intermediate-level maintenance. Twenty Australian civilian maintainers and 25 Royal Australian Navy divers and Fleet Support Unit personnel had already completed training at Pearl Harbor, with more than 230 Australians undergoing additional instruction in Hawaii. The strategic advantage of Stirling is therefore primarily measured in submarine availability and transit reduction rather than in the number of boats permanently present.

The base sits directly on the Indian Ocean side of the Australian continent and removes the requirement for submarines supporting western operating areas to begin deployments from eastern Australia and transit through the Great Australian Bight. From Garden Island, SSNs can move north toward the eastern Indian Ocean, the Indonesian archipelago and Southeast Asian approaches, or continue toward the Western Pacific. For the U.S. Navy, this provides a support point considerably farther southwest than Guam, Japan, Pearl Harbor, and the continental U.S. facilities. That dispersion matters because an SSN's military output is determined not only by the number of submarines in commission, but by how many are available in the required theater, how long they remain on station, and how quickly they can be returned to operations after maintenance or replenishment.

A submarine supported at Stirling, instead of returning across the Pacific, can devote a greater share of its deployment to anti-submarine warfare, anti-surface warfare, intelligence collection, surveillance, special operations support, sea denial, or monitoring maritime approaches. HMAS Stirling, therefore,  can increase the operational utility of the U.S. submarines assigned to the Indo-Pacific by reducing transit time and broadening the number of locations capable of supporting them. The facility also complicates attempts to disrupt allied submarine operations because maintenance, logistics and command functions are more widely distributed between Western Australia, Guam, Hawaii, Japan and continental U.S. facilities. The main limitation is the number of submarines and the capacity to maintain them.

Admiral Samuel Paparo, commander of U.S. Indo-Pacific Command, told the U.S. Senate in April 2026 that the United States could move submarines to Stirling "today," indicating that the base itself was not the principal schedule risk. He instead identified the submarine industrial base across the United States, Australia and the United Kingdom as the area requiring the greatest improvement. The U.S. Navy needs Virginia-class production to exceed two submarines per year to meet domestic fleet requirements and support AUKUS transfers, while current output remains below that level and the Columbia-class ballistic missile submarine receives priority. Production efficiency has deteriorated sharply. A Virginia-class submarine required 13 million labour hours to build in 2011; by 2026, the figure had increased to 70 million labour hours, more than five times the earlier requirement.

The increase means that simply adding money does not translate directly into proportional hull output because shipyards must also expand skilled labour, supplier capacity, quality control, component production and nuclear-qualified construction capacity. General Dynamics Electric Boat and Huntington Ingalls Industries Newport News are simultaneously supporting Virginia-class construction while the United States ramps up the Columbia-class SSBN program, which replaces the Ohio-class ballistic missile submarine fleet and therefore takes precedence within U.S. naval shipbuilding. HMAS Stirling can consequently be ready to support additional submarines before the U.S. industrial base is capable of producing enough boats to exploit that infrastructure at the planned scale. But that production constraint directly changed Australia's acquisition plan on May 30, 2026.

At a trilateral meeting in Singapore involving Australian Defence Minister Richard Marles, U.S. Secretary of Defense Pete Hegseth and UK Defence Secretary John Healey, the Virginia acquisition model was revised so that all three Virginia submarines intended for Australia would come from the existing U.S. Navy inventory rather than from a mix of in-service and newly constructed boats. Removing the newly built submarine reduces near-term demand on the Virginia production line, but it shifts the cost of the transfer from industrial capacity to American force structure. An in-service Virginia delivered to Australia is a submarine no longer available to the U.S. Navy unless shipyard output produces a replacement quickly enough to offset the transfer.

That problem becomes more significant while Los Angeles-class SSNs continue to be retired and Virginia-class construction remains below the rate required to replace them one-for-one while also growing the fleet. Australia also faces a different but related constraint because it must create enough trained personnel to crew, maintain, regulate, and support nuclear-powered submarines while simultaneously sustaining the six Collins-class boats, expanding Henderson and Stirling, and developing its future SSN-AUKUS construction infrastructure in South Australia. AUKUS therefore depends on several schedules remaining aligned: availability of three transferable U.S. Virginias, U.S. replacement production, Australian crew training, nuclear regulatory development, maintenance capacity at Stirling and Henderson, and the eventual transition toward SSN-AUKUS.

A delay in any one of these areas can leave completed infrastructure without enough submarines or leave submarines without enough trained personnel and maintenance capacity to sustain acceptable availability. Hammond's comparison with Allied submarine operations during the Second World War illustrates why Australia has repeatedly been used to support submarine forces operating north of the continent. More than 300 U.S. submarine combat patrols departed Fremantle during the war, and more than 500 patrols originated from continental Australia. A rotational submarine force also operated from Brisbane, while Royal Navy submarines used Sydney after the war until Australia's Oberon-class boats entered service.

The current arrangement is nevertheless substantially more integrated because modern SSN support requires nuclear stewardship, radiological controls, specialized maintenance, secure communications, trained nuclear-qualified personnel, and formalized command structures that did not exist in the earlier rotational model. The reactivation of Submarine Squadron 3 provides a U.S. command-and-coordination element associated with the Western Australian submarine presence, while Naval Support Activity Stirling provides shore administration and the Pearl Harbor maintenance detachment connects the base directly to the U.S. submarine-maintenance enterprise. Australian personnel are being inserted into this system before Australia owns an SSN: sailors deploy aboard American and British submarines, maintainers work on visiting boats, and divers train to the standards needed for nuclear-powered submarine support.

SRF-West is therefore not merely a deployment arrangement. It is being used as an operational training and workforce-generation mechanism intended to transfer the procedures required to operate, maintain, and regulate SSNs into the Royal Australian Navy and Australian industry before the first Australian Virginia-class submarine arrives. The sovereignty issue is consequently more precise than the binary question of whether HMAS Stirling is or is not an American base. Australia retains ownership and control of HMAS Stirling, maintains a bipartisan policy against foreign military bases on Australian soil, and specifies that SRF-West submarines will rotate through the facility rather than be permanently homeported there. 

U.S. participation operates through the Australia-U.S. Force Posture Agreement, while the United Kingdom participates under separate arrangements. At the same time, an enduring U.S. support architecture is being established inside and around the Australian installation: Submarine Squadron 3 provides command functions, Naval Support Activity Stirling supports personnel and families, U.S. maintenance specialists will work from Western Australia, and thousands of American personnel will be associated with the initiative. The operational effect is therefore more substantial than normal port access even though legal sovereignty remains Australian.

Washington gains the ability to plan repeated SSN use of Western Australia without relying on one-off political approval for each deployment cycle, while Canberra gains access to U.S. and British nuclear-submarine operating practices before assuming responsibility for its own SSNs. The central question for the 2030s is consequently not whether individual U.S. Virginia-class submarines are permanently berthed at Stirling, but whether Australia and the United States can sustain the personnel, maintenance capacity, industrial output, infrastructure and logistics required to keep several nuclear-powered submarines operational from Western Australia at the same time. Hammond's clarification settles the intended duration of access; it does not resolve the harder numerical problem of generating enough submarines, skilled workers and maintenance throughput to make that access continuously useful.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.

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