USS Colorado to Be First Virginia-Class Submarine Rotated to Australia Under AUKUS From Late 2027

The United States, Australia and the United Kingdom announced on October 26, 2026 that USS Colorado (SSN 788) will be the first U.S. Navy Virginia-class fast-attack submarine assigned to Submarine Rotational Force-West (SRF-West), the AUKUS rotation at HMAS Stirling in Western Australia, beginning in late 2027.

The designation was made in a joint statement by the U.S. Secretary of War, Australia's Deputy Prime Minister and Minister for Defence, and the UK Secretary of State for Defence, published by the U.S. Department of War. The three defense ministers said the selection "marks a significant milestone for AUKUS Pillar I and is a decisive step in strengthening collective deterrence in the Pacific." The statement said President Trump, Prime Minister Albanese and Prime Minister Burnham have described AUKUS as moving "full steam ahead."

SRF-West is projected to host up to four U.S. fast-attack submarines and one UK fast-attack submarine on a rotational basis at HMAS Stirling, a Royal Australian Navy base, according to the joint statement. The force was established at Australia's invitation and operates under the agreements between the three countries, including the U.S.-Australia Force Posture Agreement. The ministers said it is conducted consistent with obligations under the Treaty on the Non-Proliferation of Nuclear Weapons and with Australia's obligations under the South Pacific Nuclear Free Zone Treaty, the Treaty of Rarotonga.

The joint statement said SRF-West will accelerate Australia's readiness to own, operate, maintain and regulate a sovereign, conventionally armed, nuclear-powered submarine capability, and will expand maintenance options and sustainment infrastructure in the region for the AUKUS partners. The announcement comes ahead of the upcoming U.S. submarine maintenance period, beginning later this week, which the ministers said "will further demonstrate Australia's growing ability to sustain U.S. and UK nuclear-powered fast-attack submarines."

Commissioned in 2018, Colorado is the fifth Block III boat of the Virginia class, according to Naval News.

According to GlobalMilitary.net's inventory, which counts hulls by class and status, the U.S. Navy has 26 Virginia-class submarines in service, with two fitting out, six on order and nine more planned; the two most recent commissionings, in 2026, were USS Massachusetts in March and USS Idaho in April. Across all classes, the U.S. Navy has 47 attack submarines in service. The Royal Navy, which is to contribute one boat to the rotation, operates six Astute-class attack submarines, with one on order; GMN's Astute versus Virginia comparison sets the two designs side by side.

The host navy has no nuclear-powered boat of its own today. GMN's inventory of the Royal Australian Navy submarine fleet lists six conventionally powered Collins-class submarines, the whole of its submarine force.

The designation follows two earlier AUKUS Pillar I milestones reported by GMN: the United Kingdom's confirmation of a 2027 steel cut on the first SSN-AUKUS submarine, and the U.S. Navy's July 2026 award covering nine Virginia-class and five Columbia-class submarines.

The next step is the U.S. submarine maintenance period that begins this week. Colorado's rotation to Western Australia is scheduled to begin in late 2027; the joint statement gave no further timetable for the additional U.S. and UK boats that SRF-West is projected to host.