AUKUS amendment shifts Australia’s nuclear submarine procurement to in-service US vessels

The United States has agreed to supply only in-service nuclear-powered submarines to Australia under an amended AUKUS defence agreement, a decision confirmed by Defence Minister Richard Marles, US Defense Secretary Pete Hegseth, and UK Defence Secretary John Healey at the Singapore Shangri-La Dialogue. The amendment replaces the original 2021 framework, which anticipated a mix of two used submarines and one new vessel, with a commitment to provide at least three in-service Virginia-class submarines from US Navy stock within 15 years.

Marles described the strategic pivot as a "cost-effective" measure designed to streamline the complex acquisition programme. Speaking to reporters on Sunday, the deputy prime minister emphasised that maintaining a single vessel model simplifies critical operational requirements. He noted that uniformity in the fleet would significantly ease training for submariners and reduce maintenance burdens for technical personnel, thereby maximising efficiency across the supply chain.

The shift in procurement strategy comes against the backdrop of production constraints within the United States. While the US Navy currently operates 24 Virginia-class vessels, American shipyards are reportedly struggling to meet established production targets of two new boats per year. By utilising existing assets rather than waiting for new builds, the three AUKUS partners aim to accelerate Australia’s capability delivery while navigating these industrial bottlenecks.

A joint statement issued on Saturday by the three defence secretaries highlighted the administrative benefits of the new approach. The agreement aims to simplify supply chain management and operational requirements, explicitly stating that the approach enables Australia to acquire three in-service Virginia-class submarines in lieu of the previously planned mixture of new and in-service variants. The announcement was made during the Shangri-La Dialogue, a security forum attended by defence officials from approximately 45 countries.

The AUKUS submarine programme remains central to Australia’s defence posture, with government forecasts projecting costs of up to US$235 billion over 30 years. Despite the streamlined approach, the decision has drawn scrutiny in the United States, where critics have questioned the transfer of nuclear-powered assets without first replenishing US military stocks. The specific delivery timeline for the three submarines remains open-ended within the 15-year window, with no exact dates provided in the amended agreement.