Australia, UK sign landmark treaty to advance nuclear submarine cooperation

Australia and the United Kingdom have signed a landmark defence treaty cementing long-term cooperation on the development of nuclear-powered submarines under the AUKUS security partnership.

The Geelong Treaty, signed in Victoria on July 26 by Australia’s Deputy Prime Minister and Defence Minister Richard Marles and UK Secretary of State for Defence John Healey, marks a historic deepening of bilateral ties in maritime defence, Caliber.Az reports, citing the infornation on UK goverment website. 

The agreement formalises a 50-year commitment to collaborate on all aspects of the SSN-AUKUS programme—the next-generation nuclear-powered submarine project developed jointly by Australia, the UK and the United States under AUKUS Pillar I.

The treaty enables comprehensive cooperation in the design, construction, operation, sustainment, and eventual disposal of the submarines. It also lays the foundation for shared investment in workforce development, infrastructure, and regulatory systems to support Australia’s future submarine fleet. As part of the deal, a UK Astute-class submarine will rotate through HMAS Stirling naval base in Western Australia, under the Submarine Rotational Force – West.

Officials described the treaty as a critical step in strengthening trilateral defence ties and supply chain resilience.

“This is a transformative moment in our security partnership,” said Marles. “The Geelong Treaty will deliver advanced undersea capabilities for our shared security in both the Indo-Pacific and Euro-Atlantic regions.”

The treaty reaffirms both nations’ commitment to nuclear non-proliferation, ensuring alignment with the Treaty on the Non-Proliferation of Nuclear Weapons, the South Pacific Nuclear Free Zone Treaty, and safeguards agreements with the International Atomic Energy Agency. It is also consistent with the AUKUS Naval Nuclear Propulsion Agreement (ANNPA), signed earlier between the AUKUS nations.

Together, the Geelong Treaty and ANNPA are set to underpin one of the most ambitious defence industrial collaborations in recent history. The programme is expected to create thousands of jobs, bolster defence manufacturing sectors, and open new opportunities for industry in both countries.

“This treaty lays the groundwork for decades of shared innovation and operational readiness,” said UK Defence Secretary John Healey. “It is a testament to our unwavering commitment to collective security and a free and open Indo-Pacific.”

By Sabina Mammadli