SSN-AUKUS is a fleet of nuclear-powered submarines to be operated by the UK and Australian navies. Credit: BAE Systems/Business Wire.
Australia is already a signatory to the AUKUS trilateral partnership that will allows it to build nuclear-powered submarines. Credit: US Secretary of Defense/Wikipedia.
BAE Systems and ASC will construct Australia's new fleet of nuclear-powered submarines.

SSN-AUKUS is a fleet of conventionally armed, nuclear-powered submarines (SSN) to be built for the UK and Australian navies, as part of the Australia-UK-US (AUKUS) trilateral agreement signed in September 2021.

The three countries are collaborating through the AUKUS enhanced security partnership to provide Australia with nuclear-powered submarine capability and to jointly create a new class of attack submarines that are aimed at strengthening undersea capabilities, enhancing deterrence and countering China’s influence in the Indo-Pacific region.

AUKUS leverages the UK’s advanced design capabilities and integrates technologies from all three nations, including submarine technologies from the US.

In March 2024, the Australian Government chose UK-based defence company BAE Systems and submarine company ASC to construct Australia’s new fleet of nuclear-powered submarines, marking a significant advancement in the AUKUS trilateral agreement.

ASC and BAE Systems will work together to establish a joint venture to build the SSN-AUKUS submarines at the Osborne Naval Shipyard in South Australia.

SSN-AUKUS submarines development and delivery details

The SSN-AUKUS submarines for the UK Royal Navy will be constructed at the shipyard in Barrow-in-Furness, Cumbria, UK. The first batch of the new submarines is expected to be delivered in the late 2030s, which will replace the existing Astute-class submarines in the UK Navy.

The Royal Australian Navy is expected to acquire a total of eight SSN-AUKUS submarines, which will be built at the Osborne Naval shipyard in Adelaide, South Australia and will be delivered to the navy in the early 2040s.

The Australian Navy will also purchase three Virginia-class submarines from the US in the early 2030s, subject to approval from the US Congress. Under the AUKUS partnership, Australia will also have the option to purchase two more Virginia-class submarines in the late 2030s, to maintain its underwater capabilities until the delivery of the SSN-AUKUS submarines.

The SSN-AUKUS submarines are intended to replace the Collins-class diesel-electric submarines that have been in service with the Royal Australian Navy.

SSN-AUKUS submarine design details

SSN-AUKUS will be a state-of-the-art advanced submarine based on the UK’s next-generation, interoperable SSN design, integrating cutting-edge technologies from all three nations.

The integration of propulsion, sensors and weapon systems as well as the common vertical launch system in the SSN-AUKUS will be based on the Virginia-class technologies from the US. The submarine will be equipped for advanced intelligence, surveillance, underwater warfare and strike missions.

Investment details

Australia is expected to invest up to A$368bn ($244.9bn) over the next 30 years in the SSN-AUKUS development programme, which will include investments of A$2bn and A$8bn to upgrade the Osborne Naval shipyard in South Australia and the HMAS Stirling naval base in Western Australia, respectively.

Australia’s investment in the programme will also strengthen the industrial bases in the UK and the US to build and support the submarines.

The UK government will invest £5bn through 2025 to upgrade the country’s nuclear enterprise and fund the SSN-AUKUS submarine development. The investment is expected to be followed by continuous funding over the next ten years to support the submarine development programme.

The UK Ministry of Defence granted BAE Systems £4bn funding in October 2023 for the upcoming phase of the SSN-AUKUS programme.

The funding will support BAE Systems in advancing the detailed design phase of the programme and acquiring necessary long-lead items, extending development work through 2028.

The US is investing $2.4bn in its submarine industrial base from 2023 to 2027 to increase the production capacity of Virginia-class SSNs.

Contractors involved

BAE Systems received a contract worth £85m ($117.3m) from the UK’s Ministry of Defence to support early design and concept work on the SSN-AUKUS submarines in September 2021.

Rolls-Royce Submarines, a Rolls-Royce subsidiary based in Derby, UK, will provide the nuclear reactors for Australia’s AUKUS submarines.

Babcock International, a UK-based nuclear engineering services company, will support the nuclear infrastructure development, workforce upskilling and regulatory and safety standards for the SSN-AUKUS programme.