Australia and Britain Sign 50-Year Treaty to Strengthen AUKUS Nuclear Submarine Partnership

Australia has signed a landmark treaty with Britain to deepen cooperation on the AUKUS nuclear-powered submarine program, a defense initiative aimed at countering China’s growing influence in the Indo-Pacific. The agreement, announced Saturday by Australian Defence Minister Richard Marles, was finalized in Geelong, Victoria, with Britain’s Defence Secretary John Healey.

The treaty, dubbed the “Geelong Treaty,” will guide collaboration for the next 50 years on the design, construction, operation, sustainment, and eventual disposal of SSN-AUKUS submarines. It builds on the trilateral AUKUS pact formed in 2021 between Australia, Britain, and the United States.

Britain’s Ministry of Defence estimates the deal could generate up to £20 billion ($27.1 billion) in exports over the next 25 years, bolstering its submarine program and industrial base. For Australia, the AUKUS project represents its largest defense investment, valued at A$368 billion over three decades, including significant contributions to U.S. shipbuilding capacity. Earlier this month, Canberra made its second A$800 million payment to the U.S. under the agreement.

The treaty was signed amid Australia’s largest military exercise, Talisman Sabre, involving 40,000 troops from 19 nations. Britain has ramped up its role in the drills, deploying the aircraft carrier HMS Prince of Wales to participate alongside Australian and U.S. forces.

The pact comes as U.S. President Donald Trump’s administration conducts a review of AUKUS, though Australia remains confident the program will move forward as planned, reinforcing Western security ties in the region for decades to come.