On 26 July 2025 in Geelong, Australia, the Honourable Richard Marles MP, Deputy Prime Minister and Minister for Defence, Australia and the Right Honourable John Healey MP, Secretary of State for Defence, United Kingdom (UK) signed the bilateral Nuclear-Powered Submarine Partnership and Collaboration Treaty (the Geelong Treaty) at the UK-Australia Defence Ministers’ Meeting in Geelong, Victoria. The Geelong Treaty is a historic agreement, the commitment for the next 50 years of UK-Australian bilateral defence cooperation under AUKUS Pillar I.
The Geelong Treaty will enable comprehensive cooperation on the design, build, operation, sustainment, and disposal of our SSN-AUKUS submarines. It will support the development of the personnel, workforce, infrastructure and regulatory systems required for Australia’s SSN-AUKUS programme, as well as support port visits and the rotational presence of a UK Astute-class submarine at HMAS Stirling under Submarine Rotational Force – West.
The Treaty builds on the strong foundation of trilateral cooperation between Australia, the UK and the United States, advancing the shared objectives of the AUKUS partnership. It will enable the development of SSN-AUKUS and resilient trilateral supply chains.
Importantly, the Geelong Treaty is consistent with Australia’s and the UK’s respective international nuclear non-proliferation obligations, including under the Treaty on the Non-Proliferation of Nuclear Weapons, the South Pacific Nuclear Free Zone Treaty and its Protocols, and Australia’s safeguards agreements with the International Atomic Energy Agency, and the trilateral AUKUS Naval Nuclear Propulsion Agreement (ANNPA).
Together with the ANNPA, the Treaty will enable Australia and the UK to deliver a cutting-edge undersea capability through the SSN-AUKUS programme, and in doing so, support stability and security in the Euro Atlantic and the Indo-Pacific for decades to come, drive defence as an engine for growth across our two nations, create thousands of jobs, build our respective submarine industrial bases and supply chains, and provide new opportunities for industry partners.
