The Pentagon announced Monday that USS Colorado will be the first American submarine assigned to Submarine Rotational Force-West in Australia. The move gives the planned multinational rotation its first identified U.S. Navy submarine.

The force will comprise four U.S. fast attack submarines and one UK fast attack submarine. USS Colorado is a Virginia class fast attack submarine operated by the U.S. Navy.

War Secretary Pete Hegseth announced Colorado’s assignment in conjunction with representatives from Australia and the United Kingdom. The announcement places the submarine at the front of the developing rotational force.

Submarine Rotational Force-West is expected to reach initial operating capacity in 2027. It will support a fleet of American and British submarines powered by nuclear energy at Australia’s HMAS Stirling installation near Perth.

“SRF-West will accelerate Australia’s readiness to own, operate, maintain, and regulate a sovereign, conventionally armed, nuclear-powered submarine capability, as well as support submarine deployments by expanding maintenance options and sustainment infrastructure in the region for AUKUS partners,” a Pentagon statement read.

The statement links the rotation to Australia’s preparation for operating and maintaining its own sovereign submarine capability. It also identifies expanded maintenance options and sustainment infrastructure as central parts of the plan.

AUKUS is a trilateral security partnership involving Australia, the United Kingdom and the United States. The partnership is designed to promote a safe Indo-Pacific region through cooperation among the three participating nations.

The United States stood up Naval Support Activity Stirling in Western Australia in June. The activity supports American personnel and others connected to Submarine Rotational Force-West.

A service release said the activity provides “services and programs for U.S. service members, civilian personnel, contractors and their families” assigned to the rotational force. Those services establish support for the personnel who will take part in the submarine presence.

According to the Pentagon, the new rotational force will increase maintenance resources available in the region. It will also bolster the sustainment framework supporting submarine operations involving the AUKUS partners.

Hegseth met with senior Australian and British officials in Singapore on May 30 to discuss the partnership’s objectives. Their talks focused on AUKUS goals for defending the Indo-Pacific region.

Australian Deputy Prime Minister and Minister for Defence Richard Marles participated in the meeting. UK Secretary of State for Defence John Healey also joined Hegseth for the discussions.

During the meeting, Australian and UK officials confirmed that Australia remained scheduled to receive a conventionally armed submarine powered by nuclear energy. That delivery is slated to occur within the next few years.

The three nations also focused on developing and fielding uncrewed undersea vehicles. Those vehicles are intended to provide both defensive and offensive military capabilities throughout the region.

Colorado’s assignment connects the first named U.S. submarine to the broader 2027 operating timeline. The rotation is planned to bring together American and British fast attack submarines at the Australian installation.

The rotational model centers on submarine presence, maintenance resources and sustainment at HMAS Stirling. At the same time, Australia is preparing to own, operate, maintain and regulate its sovereign submarine capability.

With USS Colorado now identified, the Pentagon has named the first American submarine for Submarine Rotational Force-West. The remaining planned force consists of additional U.S. submarines and a UK submarine operating through the Australian installation.