Within the framework of the AUKUS agreement, the Australian government celebrated the arrival of the U.S. Navy’s attack submarine USS Vermont (SSN-792) at HMAS Stirling Naval Base, located on the country’s western coast. The arrival marks the beginning of a new Shipyard Tendered Maintenance Period (STMP), a key stage in the process of technical and industrial cooperation aimed at the future joint operation of nuclear-powered submarines on Australian territory.
AUKUS — an alliance formed by Australia, the United Kingdom, and the United States — was officially announced in 2021 as a security and defense pact designed to strengthen allied presence in the Indo-Pacific. Its main component is the Nuclear-Powered Submarine Program (SSN-AUKUS), through which Australia will replace its current Collins-class submarines with nuclear-powered units developed alongside its Anglo-Saxon partners. The agreement also includes technology transfer, personnel training, industrial cooperation, and joint development of capabilities in areas such as cyber defense, artificial intelligence, and autonomous systems — positioning Canberra as a strategic partner in regional deterrence against China’s growing naval power.
Regarding the submarine’s arrival, this is the second full maintenance carried out on a U.S. nuclear-powered submarine outside U.S. territory, following the 2024 maintenance of the USS Hawaii (SSN-776) alongside the support ship USS Emory S. Land (AS-39). Unlike that occasion, the current maintenance will take place without a support vessel, representing a major step forward in the gradual transfer of technical capabilities to the Royal Australian Navy (RAN).
According to the Australian Ministry of Defence, this year’s planned maintenance package is broader and more complex, more accurately reflecting the type of work that will be performed regularly once the Submarine Rotational Force – West (SRF–West) begins permanent operations at HMAS Stirling in 2027. This process will allow for the rotational presence of U.S. and U.K. attack submarines in Australia before the introduction of the first jointly built SSN-AUKUS submarines.
The USS Vermont’s STMP involves the direct participation of Australian technical personnel who, in coordination with specialists from the Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility (PHNSY & IMF), will play a central role in maintenance, diagnostics, and critical system repairs. Currently, 19 military technicians from ASC and two representatives from Raytheon and Thales Australia are undergoing training in Pearl Harbor as part of a knowledge transfer and sovereign capability development program.
This training and technical cooperation form part of a phased plan agreed upon by the AUKUS member nations, culminating in the Initial Operational Support (IOS) milestone scheduled for 2027. From that point on, Australia will consolidate its role as a key logistical partner in the maintenance and operation of nuclear attack submarines, directly contributing to the projection and strategic deterrence of allied forces in the Indo-Pacific.
Finally, this development comes just days after U.S. President Donald Trump confirmed the sale of Virginia-class nuclear submarines to Australia, dispelling doubts about the continuity of AUKUS. In this context, the maintenance work on the USS Vermont at HMAS Stirling represents another step stemming from that political decision, strengthening the logistical, technical, and human capabilities that will enable the Royal Australian Navy to sustain and operate its future U.S.-built nuclear attack submarines, as well as those jointly developed with the United Kingdom — a necessary precursor to training crews and establishing operational and sustainment doctrine for this class of platforms.
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