U.S. military footprint in Australia set to deepen as AUKUS submarine deadline approaches

Australia and the United States are preparing to expand American military activity in Australia beyond existing arrangements, with Defence Minister Richard Marles confirming discussions over broader and more complex cooperation spanning land, sea, air, cyber and space. The talks took place in Washington as the two countries marked 75 years of the ANZUS alliance and prepare for another Australia–United States Ministerial Consultations meeting later in 2026.

Marles said the next stage of U.S. force posture should not necessarily be understood as a simple increase in troop numbers. Existing arrangements already include substantial Marine rotations and preparations for American nuclear-powered submarines, while the discussions with U.S. Secretary Pete Hegseth focused on increasing the breadth and operational complexity of what the two militaries do together. More detailed announcements are expected at AUSMIN later this year.

The most important near-term milestone remains Submarine Rotational Force-West at HMAS Stirling in Western Australia. American personnel are already working at the base, and Australia says the programme remains on schedule to begin by the end of 2027, bringing rotational U.S. Virginia-class nuclear-powered submarines and British submarines to Western Australia as part of the pathway toward an Australian nuclear-powered submarine capability under AUKUS.

What exactly do Australia and the United States mean by expanding force posture?

Force posture covers much more than permanently stationing soldiers in another country. It includes rotational deployments, joint exercises, access to bases, logistics, maintenance, fuel and ammunition storage, intelligence cooperation and the infrastructure required to operate forces during a crisis.

Marles said Australia and the United States are discussing an expansion in both the breadth and complexity of their existing cooperation. He specifically identified land, sea, air, cyber and space as areas across which the alliance is becoming more integrated.

That distinction matters politically. Australia can substantially deepen military integration with the United States without announcing a new permanent American base or dramatically increasing the number of U.S. personnel residing continuously in the country.

From Washington’s perspective, access and logistical resilience can be as important as permanent basing. Aircraft, submarines and ships need locations where they can refuel, repair, reload and disperse, while cyber and space cooperation can improve awareness and communications across the Indo-Pacific.

Australia’s geography makes it particularly valuable because the continent provides strategic depth relative to many U.S. facilities closer to China.

Why is HMAS Stirling becoming central to the future Australia–U.S. military relationship?

HMAS Stirling near Perth will host Submarine Rotational Force-West, one of the most consequential steps in the AUKUS programme. Australia, the United States and United Kingdom confirmed earlier this year that the necessary arrangements for the rotational force had been finalised and that the programme remained on track for 2027.

Australia is investing up to A$8 billion expanding HMAS Stirling, with approximately 3,000 direct Australian jobs expected to be associated with that work. The U.S. Navy has re-established Submarine Squadron 3 to oversee American nuclear-powered submarines rotating through Western Australia, and American personnel have already begun preparations at the base.

The strategic logic is straightforward. U.S. submarines operating from Western Australia can spend more time in the Indo-Pacific and less time transiting from bases farther away, while Australian sailors and technicians gain practical experience operating alongside nuclear-powered submarine crews.

For Australia, the rotation is also an apprenticeship programme. Canberra plans eventually to operate its own nuclear-powered submarines, including U.S. Virginia-class vessels in the early 2030s and later the jointly developed SSN-AUKUS class.

Failure to establish the maintenance, nuclear stewardship and workforce systems required at Stirling would therefore threaten the wider AUKUS timetable.

How does the Henderson Defence Precinct support the U.S. submarine strategy?

Marles said his Washington discussions also covered the Henderson Defence Precinct, another major Western Australian infrastructure investment connected with naval shipbuilding and sustainment. Australia sees Henderson and HMAS Stirling as complementary facilities capable of supporting greater maintenance activity for U.S. Virginia-class submarines.

This has an important strategic implication for the United States. Every maintenance task that can be performed in Australia reduces the need for a submarine to return to an American shipyard, potentially increasing operational availability.

Marles directly linked that increased maintenance capability with the eventual transfer of Virginia-class submarines to Australia. The logic is that improving U.S. Navy availability helps create the operational capacity Washington would need before releasing submarines to the Royal Australian Navy in the early 2030s.

That makes Australian industrial investment part of the American submarine problem rather than simply a domestic shipbuilding programme. The AUKUS agreement works only if both countries expand maintenance and industrial capacity fast enough to support more submarines overall.

Is Washington still pressuring Australia to increase defence spending?

The question remains politically sensitive. Hegseth has repeatedly urged allies to increase defence spending, and the Pentagon’s public language around the latest meeting again emphasised the need for allied capabilities to match the strategic threat.

Marles responded by stressing that Australian defence spending has already increased substantially. He said spending is around 2.8% of gross domestic product under the NATO comparison and is planned to reach 3% by 2033, with an additional A$117 billion injected across the decade through successive government decisions.

Canberra’s argument is therefore that Australia is already carrying an unusually large burden compared with many U.S. partners. Marles cited spending levels above Britain, France and Germany using the same comparison methodology.

Washington may still seek faster or greater investment in particular capabilities, but the dispute increasingly concerns what Australia buys and how quickly capabilities become available rather than whether defence spending is rising at all.

The force-posture expansion is one way Australia can demonstrate strategic contribution beyond headline budget percentages.

How does China’s growing Pacific influence affect Australia–U.S. defence planning?

The Washington talks occurred alongside a broader Western effort to strengthen engagement across the Pacific Islands. Australia and the United States have announced combined commitments worth about US$580 million for Pacific initiatives as China expands its diplomatic, infrastructure and security relationships across the region.

Australia consistently frames its U.S. alliance as supporting deterrence and regional stability rather than preparing for an inevitable war with China. Marles said increased American force posture is intended to strengthen peace and stability across the Indo-Pacific.

China takes a different view of AUKUS, arguing that the nuclear-submarine arrangement contributes to an arms race and undermines regional non-proliferation norms. Beijing is also expanding its own military capabilities and diplomatic reach across the Pacific.

Pacific Island governments frequently resist being forced to choose between larger powers, however, and often prioritise climate, development, policing and infrastructure alongside strategic security.

That means Australia and the United States are increasingly combining hard defence integration with civilian investment and regional assistance rather than treating Pacific competition as exclusively military.

What does the 75th anniversary of ANZUS reveal about how the alliance has changed?

The ANZUS Treaty was signed in 1951 and formalised security cooperation among Australia, New Zealand and the United States following the Second World War. Australian leaders describe it as the cornerstone of the country’s strategic policy.

Yet today’s alliance looks very different from the arrangement originally envisaged. Cyber operations, space systems, nuclear-powered submarines, artificial intelligence and integrated logistics were not part of the 1951 security environment.

The current force-posture discussions therefore show how the alliance is adapting rather than merely celebrating longevity. Australia is becoming more deeply integrated into American military planning while simultaneously investing in sovereign industrial capacity.

That creates benefits and risks. Integration improves deterrence and access to advanced capability, but it also means Australian facilities could become more strategically significant during a major conflict.

The political debate will increasingly concern how much integration Australia wants and what independent decision-making safeguards accompany it.

What are the key takeaways from the latest Australia–United States defence talks?

• Australia and the United States are discussing an expansion in the breadth and complexity of U.S. force-posture activities in Australia.
• Richard Marles said future cooperation will extend across land, sea, air, cyber and space rather than being defined simply by additional troop numbers.
• More detailed force-posture announcements are expected at the AUSMIN meeting later in 2026.
• American personnel are already at HMAS Stirling preparing for Submarine Rotational Force-West.
• The submarine rotation remains scheduled to begin by the end of 2027.
• Australia is investing up to A$8 billion expanding HMAS Stirling and is developing the Henderson Defence Precinct to support naval maintenance.
• Canberra says defence spending is approximately 2.8% of GDP under the NATO comparison and will reach 3% by 2033.
• Australia and the United States are simultaneously increasing engagement with Pacific Island states amid growing strategic competition with China.

Is Australia becoming an increasingly important operating base for the United States in the Indo-Pacific?

Yes, although “base” can oversimplify what is happening. Australia is becoming a more important platform from which U.S. forces can train, maintain equipment, rotate personnel, operate submarines and access strategic infrastructure, but much of that activity occurs through Australian facilities and jointly agreed arrangements rather than traditional permanent overseas bases.

The trend is nevertheless unmistakable. HMAS Stirling will support American nuclear-powered submarines, Henderson will help expand maintenance capacity, Marine rotations are established, and future cooperation is moving deeper into cyber and space.

The alliance is therefore evolving from a relationship built around fighting alongside one another into one in which the two militaries are increasingly designed to operate through interconnected infrastructure.

For Canberra, the strategic calculation is that deeper integration increases deterrence in a more dangerous region. The unresolved question is how far that process can advance before Australians begin demanding a clearer debate about the obligations, vulnerabilities and sovereign choices that come with becoming one of Washington’s most important military partners in the Indo-Pacific.