U.S. Navy nuclear submarine arrives in Australia for maintenance

The U.S. Navy attack submarine USS Colorado (SSN 788) arrived at HMAS Stirling in Western Australia on Oct. 27 to begin a scheduled monthlong maintenance period. For the first time, Australian civilian technicians will carry out routine maintenance on a Virginia-class submarine in Western Australia, working alongside American shipyard specialists, with the U.K. Royal Navy also taking part in the work.

More than 30 trained and certified technicians from Australian shipbuilder ASC Pty Ltd. will work on the boat alongside specialists from Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility, the U.S. Navy yard in Hawaii where the Australian workers were trained.

The visit comes one day after Secretary of War Pete Hegseth and his Australian and British counterparts issued a joint statement on Oct. 26 naming Colorado as the first U.S. Navy Virginia-class submarine assigned to Submarine Squadron 3, the American squadron reactivated at HMAS Stirling in June. When Colorado returns in late 2027, it is set to help formally establish Submarine Rotational Force-West, the arrangement under which up to four U.S. submarines and one British submarine will operate on rotation from the base south of Perth.

“This maintenance period brings us closer to establishing SRF-West,” said U.S. Navy Rear Adm. Doug Adams, director of AUKUS, International & Systems. “Our Lead Maintenance Activity, Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility, is doing a great job ensuring the Australian personnel trained in Hawaii are ready and able to support our submarines.”

Colorado’s visit is the fourth submarine maintenance period in Western Australia since the AUKUS partnership was formed and the third in the past 12 months, and each one has handed Australia a larger share of the work. USS Hawaii (SSN 776) was serviced at Stirling in 2024 with help from the submarine tender USS Emory S. Land (AS 39), while USS Vermont (SSN 792) arrived in October 2025 for a larger and more complex maintenance package that was carried out without a tender. The British submarine HMS Anson followed with its own maintenance period in February 2026, and Colorado is the sixth nuclear-powered attack submarine to visit Stirling since the AUKUS partners announced Australia’s path to a nuclear-powered fleet.

The latest period will also be the first to use several new pieces of Australian-built infrastructure together, including a custom-made metal safety walkway around the submarine’s sail known as a “racetrack,” nuclear submarine upgrades to the base’s Diamantina Pier, a pure water plant, a high-pressure air compressor and a dehumidifier.

“During last year’s maintenance period, we successfully delivered pure water from an Australian-designed and built plant and validated the sail racetrack was fit for purpose. During the U.K.’s maintenance period in February, we validated the high-pressure air compressor and dehumidifier systems. Now, with the racetrack, we’re using it to conduct maintenance, utilizing the pier upgrades, and leveraging a workforce of about three dozen fully qualified and certified Australian civilian nuclear-powered submarine maintenance workers,” said U.S. Navy Capt. Jason Pittman, commander of Submarine Squadron 3.

Australian officials said the visits are building the country’s ability to keep allied submarines in port longer and return them to sea on time, which it will need before the rotational force begins operating.

“These maintenance periods have been critical to Australia being on track to start SRF-West in 2027,” said Royal Australian Navy Rear Adm. David Mann, head of the Australian Submarine Agency’s Virginia Division.

The British side will be directly involved in the work on the American boat, which officials presented as a way to bring all three navies closer to common maintenance practices.

“The more the three nations work together to maintain submarines – whether American or British – the faster we’ll be able to uplift our Australian partner’s knowledge and skills and increase commonality across our submarine forces,” said Sir Stephen Lovegrove, the U.K. Prime Minister’s Special Representative for AUKUS.

Under the first pillar of AUKUS, Australia plans to buy three in-service Virginia-class submarines from the United States before moving to the new SSN-AUKUS design, and the port visits are intended to prepare its workforce and facilities to maintain and operate a conventionally armed, nuclear-powered fleet of its own. Ahead of Colorado’s arrival, about 20 Australian civilian maintainers and 25 Royal Australian Navy divers, Fleet Support Unit officers and sailors had completed training at Pearl Harbor, and more than 230 others were still training in Hawaii, USNI News reported in June.

“The success of any maintenance period comes down to the people on the deckplates, and the Australian personnel stepping aboard our ship are true professionals,” said U.S. Navy Capt. Justin Reeves, commanding officer of USS Colorado.