Future: AUKUS (SSN-A) Class
The SSN-AUKUS, also known as the SSN-A, is a planned class of nuclear powered attack submarine to replace the UK's Astute Class and Australia's Collins Class submarines.
SSN-AUKUS concept image
As with the current programmes, the UK's submarines will be built by BAE Systems at Barrow-in-Furness and the nuclear propulsion units at Rolls Royce in Derby. Rolls Royce will also build all the nuclear reactors for Australia's submarines.
The Astute Class replacement project began in 2018, which was later named the Submersible Ship Nuclear Replacement (SSNR). The ongoing SSNR design was renamed SSN-AUKUS in March 2023, under the 2021 AUKUS trilateral security partnership, when Australia joined the programme and additional US technology was incorporated into the design.
In October 2023, the UK government announced a series of contracts with BAE Systems, Rolls-Royce and Babcock, collectively worth £4 billion, to support the design and development of the submarine class up to 2028. These contracts will fund the finalization of the submarine design, as well as procure long-lead items for the first UK submarine.
In June 2025, the UK Ministry of Defence announced that the UK would build up to 12 SSN-AUKUS submarines. Work will begin by 2030, with a view to entering Royal Navy service toward the end of the 2030's
When in service with the Royal Navy and the Royal Australian Navy, submarine crews will train and patrol together and undertake joint maintenance and support. Components and parts will be shared with the US.
The class will be powered by Rolls-Royce's pressurised water reactors (PWR). The submarines will displace over 10,000 tonnes.
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