See also:
- HMAS Stirling and Submarine Rotational Force – West
- Log of US Navy ship visits to Darwin, 2000 – 2013, (updated 28 September 2013)
UPDATES:
29 October 2026
USS Colorado (SSN 788) arrived at HMAS Stirling on 27 October for a month-long scheduled Submarine Maintenance Period, as the first arrival at U.S. Naval Support Activity Stirling.
According to the U.S. Department of War:
‘The visit marks the fourth submarine maintenance period in Western Australia since the establishment of the Australia, U.K., U.S. trilateral security partnership and highlights ongoing progress under AUKUS pillar one. The USS Colorado is the sixth nuclear-powered attack submarine to visit HMAS Stirling following the announcement of the AUKUS Optimal Pathway in 2023 and the third to undergo maintenance in Australia in the last 12 months.
‘Secretary of War Pete Hegseth and his Australian and U.K. counterparts issued a joint statement Oct. 26, naming the USS Colorado as the first U.S. Navy fast-attack submarine assigned to the reactivated Submarine Squadron 3. The boat will help formally establish Submarine Rotational Force – West upon its planned return in late 2027.
‘Over the coming weeks, more than 30 trained and certified Australian civilian maintenance technicians will perform routine maintenance on a submarine in Western Australia for the first time, working alongside specialists assigned to Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility, Hawaii.’
The Australian and U.S. governments announced the designation of the USS Colorado as the first Virginia-class submarine assigned to Submarine Rotational Force-West from late 2027.
10 June 2026
The Commander, Submarine Force U.S. Pacific Fleet re-established Submarine Squadron 3 (CSS-3), previously decommissioned in 2012, to operate from HMAS Stirling in Western Australia in support of the establishment of Submarine Rotational Force – West in 2027.
30 May 2026
Under AUKUS arrangements, the U.S. Navy established Naval Support Activity Stirling (NSA Stirling) to support US and UK nuclear-powered submarine activity at HMAS Stirling for the initiation of Submarine Rotational Force West in 2027. NSA Stirling is organizationally related to Naval Support Group Japan.
‘Naval Support Activity Stirling will provide support services and programs for U.S. service members, civilian personnel, contractors and their families assigned to SRF-West.’
‘Through SRF-West, U.S. and U.K. nuclear-powered fast-attack submarines (SSNs) will conduct rotations from the Royal Australian Navy base HMAS Stirling starting in 2027.
Rear Adm. Chris Cavanaugh, Commander, Submarine Force, U.S. Pacific Fleet emphasized that the reactivated squadron enhances operations in the theater. “Adding an additional forward-positioned submarine squadron in the Indo-Pacific enhances our presence, agility, and responsiveness across a range of operations,” said Cavanaugh. “CSS-3 enables our submarines and crews to respond rapidly in support of the U.S. joint force mission of regional deterrence.”
Naval Support Japan, U.S. Navy Japan, ‘Welcome to Naval Support Activity Stirling’, America’s Navy, [accessed 29 October 2026].
22 February 2026
UK attack submarine HMS Anson arrived c. 22 February for an extended Submarine Maintenance Period.
‘Around 100 personnel will contribute to the UK Submarine Maintenance Period (UK SMP) including members of the Royal Navy, the UK Submarine Delivery Agency, Royal Australian Navy, ASC Pty Ltd, and Pearl Harbor Naval Shipyard.’
Speaking during the USS Vermont SMP in November 2025, a RN AUKUS spokesperson said ‘The U.K. does not consider a U.S. submarine maintenance availability at HMAS Stirling to be a U.S.-only maintenance availability… Every submarine maintenance period here is trilateral.’
28 November 2025:
USS Vermont (SSN 792) entered port for a month-long Submarine Maintenance Period commencing on 29 October, leaving port on 28 November 2025.
The work will be carried out by ASC, together with US personnel from Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility. 13 of the Vermont’s crew of 134 are RAN trainees following nuclear boar training from the US.
This was ‘the first submarine maintenance period without the support of a U.S. submarine tender—a specialized vessel that provides mobile repair and supply services….and was the first time a maintenance availability at this level has ever been done on a Virginia-class outside the United States.
‘At the center of that effort was a blended American and Australian maintenance team led by Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility (PHNSY & IMF), whose flyaway workforce provided the technical backbone for the submarine’s availability in Australia and demonstrated the ability of allied forces to operate as a single, integrated maintenance team.’
US submarine visits to HMAS Stirling, 2022 – 2025
| Vessel name | ID no | Dates | Class | Block / Flight | Homeport | Unit |
| USS Colorado | SSN 788 | 2026.10.27 – | Virginia | III | Naval Support Activity Stirling | Submarine Squadron 3 |
| USS Vermont | SSN 7922 | 2025.10.25 – 2025.11.28 | Virginia | IV | Joint Base Pearl Harbor-Hickam | Submarine Squadron 1 |
| USS Minnesota | SSN 783 | 2025.02.25 – 2025.3.01 (+) | Virginia | II | Naval Base Guam | Submarine Squadron 15 |
| USS Hawaii # |
SSN 776 | 2024.08.?? – 2024.09.?? | Virginia | I | Joint Base Pearl Harbor-Hickam | Submarine Squadron 1 |
| USS Annapolis | SSN 760 | 2024.03.?? – ? | Los Angeles | III | Naval Base Guam | Submarine Squadron 15 |
| USS North Carolina | SSN 777 | 2023.08.0? – ? | Virginia | I | Joint Base Pearl Harbor-Hickam | Submarine Squadron 1 |
| USS Asheville | SSN 758 | 2023.03.01 – 2023.03.20 | Los Angeles | III | Naval Base Guam | Submarine Squadron 15 |
| USS Mississippi | SSN 782 | 2022.11.28 – 2022.12.01 | Virginia | II | Joint Base Pearl Harbor-Hickam | Submarine Squadron 1 |
| USS Springfield # | SSN 761 | 2022.04.22 – 2022.04.28 | Los Angeles | III | Naval Base Guam | Submarine Squadron 15 |
Note: * = in port at least this day. + = in port within this period. # = 3 week maintenance visit with Emory S. Land-class submarine tender
US attack submarine visits, 1976-1982