US expands personnel at HMAS Stirling in Western Australia for AUKUS submarine force

The United States has formalised a framework for a military presence at HMAS Stirling in Western Australia, planning to station about 2,300 U.S. personnel to support the Submarine Rotational Force West under the AUKUS partnership. The arrangement includes the re‑activation of Submarine Squadron 3 and extensive upgrades to the base, with more than $6 billion in construction work underway.

Western Australian Premier Roger Cook reiterated that the facility will not become a U.S. base on Australian soil, describing the governance framework as necessary for the rotating U.S. submarines to operate safely. He noted rapid population growth in the Rockingham‑Kwinana district, with roughly 700 families moving in each month to accommodate the expanded defence activity. Australian officials maintain that HMAS Stirling remains sovereign Australian territory, while U.S. officials treat the site as a Naval Support Activity.

The development reflects deeper defence cooperation between the United States and Australia, with the United States seeking a permanent logistical foothold to sustain its submarine deployments in the Indo‑Pacific region.