DSEI 2025: Ship Submersible Nuclear AUKUS at the Heart of British and Australian naval strategy.

At the DSEI 2025 exhibition in London, a Royal Navy stand highlighted the SSN-AUKUS program, a central project of the trilateral alliance between the United Kingdom, Australia and the United States. The presentation emphasized the role of these future nuclear-powered attack submarines, designed to replace the Astute class from the late 2030s for the Royal Navy and to form Australia’s first nuclear-powered submarine fleet in the 2040s. This program, stemming from the AUKUS agreement signed in September 2021, is intended to strengthen allied undersea capabilities in the Indo-Pacific and ensure greater interoperability between the three navies.
Follow Army Recognition on Google News at this link

The SSN-AUKUS is based on a next-generation British design, incorporating American technologies derived in particular from the Virginia class (Picture source: Army Recognition)

The SSN-AUKUS is based on a next-generation British design, incorporating American technologies derived in particular from the Virginia class. These conventionally armed but nuclear-powered submarines are intended to conduct intelligence, surveillance, undersea warfare and strike missions. Construction will be divided between the British shipyards at Barrow-in-Furness and the Australian facilities at Osborne, with a schedule foreseeing the delivery of the first British-built submarines in the late 2030s and the entry into service of the first Australian units in the early 2040s.

In the meantime, Canberra plans to address the capability gap created by the gradual withdrawal of the Collins class by acquiring three Virginia-class submarines from the United States in the early 2030s, with an option to purchase two more. This transitional phase will allow the Royal Australian Navy to maintain an operational submarine capability until the SSN-AUKUS becomes available. The United Kingdom, for its part, intends to build up to twelve submarines, supported by investments in BAE Systems and Rolls-Royce facilities to sustain a production tempo of one submarine every eighteen months.

The program involves extensive industrial cooperation. BAE Systems, Rolls-Royce and Babcock are the main contractors in the United Kingdom, while in Australia BAE Systems is working in partnership with ASC through a joint venture. Rolls-Royce will supply the nuclear reactors for the Australian submarines, manufactured and assembled in the United Kingdom. The financial commitment is substantial: in 2023 London allocated £5 billion to support the program and the wider nuclear enterprise, while Canberra plans to invest around A$368 billion over thirty years, part of which will fund the modernization of local naval infrastructure.

Cooperation goes beyond construction. Since 2023, Australian officers have been integrated into both the American and British navies as well as their industrial bases to train in nuclear propulsion standards. From 2027, rotations of American and British submarines to Australia will support this gradual capability-building process and provide operational continuity. This step-by-step approach illustrates the long-term nature of the partnership, formalized in July 2025 by a fifty-year bilateral treaty between London and Canberra.

The issue of nuclear proliferation has sparked debate, as Australia is a non-nuclear-weapon state under the Nuclear Non-Proliferation Treaty. However, the three partners stress that the transfers concern nuclear propulsion only and not weapons. The reactors will be sealed and will not require refueling during the submarines’ service life. Specific commitments have been made with the International Atomic Energy Agency to ensure transparency and compliance with non-proliferation standards.

The SSN-AUKUS program stands as one of the most ambitious naval projects of the early twenty-first century. Built by BAE Systems with support from Rolls-Royce and Babcock, it reflects a long-term industrial and strategic cooperation between three maritime powers. While it is intended to enhance allied presence in the Indo-Pacific, it also underscores the challenges posed by the spread of nuclear propulsion technology, now accessible to a state that previously operated only a conventional submarine fleet.