Australia and US discuss expanded force posture as AUKUS submarine rotation nears

Australia and the United States have used the 75th anniversary of the ANZUS alliance to review a growing US military presence and preparations for a rotational submarine force in Western Australia.

Australian Defence Minister Richard Marles said Submarine Rotational Force–West at HMAS Stirling remains on track to begin by the end of 2027. US personnel are already in Australia preparing the facility and operating arrangements.

What has been confirmed

Under the AUKUS plan, conventionally armed, nuclear-powered US and UK submarines are expected to rotate through HMAS Stirling. Australia says this will help build the workforce, regulatory experience and infrastructure needed for its own future nuclear-powered submarine capability.

Marles also said US force posture is growing across multiple domains. Logistics, air, cyber and space cooperation were discussed, with more detail expected through ministerial talks. The public statements did not announce a new permanent US base or specify every deployment.

Strategic rationale and scrutiny

Australian officials cite China’s military build-up and a less predictable Indo-Pacific security environment. That is the government’s policy assessment; it does not eliminate domestic debate over sovereignty, cost, nuclear stewardship and dependence on US decisions.

Marles said Australia’s defence spending is equivalent to about 2.8% of GDP under the NATO measure and is planned to reach 3% by 2033. Spending comparisons can vary with accounting methods, so project delivery, readiness and capability are more informative than a percentage alone.

Sources: Australian ministerial doorstop; official meeting remarks; US meeting readout.

Richard Marles and Pete Hegseth meet at the Pentagon on September 2. Photo: AP via SBS.