AUKUS defence ministers have announced the first signature project under Pillar 2 of the partnership, focused on the joint development of payloads for uncrewed underwater vessels, with first capabilities expected in service by 2027, the UK Defence Journal understands.

The project was announced at a meeting in Singapore on 30 May by Defence Secretary John Healey, US Secretary of War Pete Hegseth and Australian Deputy Prime Minister Richard Marles. The work will see the three nations jointly develop payloads, including sensors and weapons systems, that can be deployed across all three fleets of uncrewed underwater vessels, with the aim of increasing collective strength and deterrence across the Indo-Pacific and Euro-Atlantic.

Healey said: “AUKUS is delivering for our security and for our economy. Together we are announcing ground-breaking underwater capabilities that will keep Britain safe, backing British businesses that are driving growth, and standing shoulder to shoulder with our closest allies. This is what modern defence looks like. We’re stepping on the accelerator to develop cutting-edge tech to boost our collective deterrence and support our shared security.”

For the Royal Navy, the payloads will support detection of underwater threats to UK and allied critical undersea infrastructure, with the ability to integrate payloads developed in the United States and Australia. The capability is intended to reinforce the future SSN-AUKUS attack submarine fleet and to drive the Royal Navy’s transition to a Hybrid Navy blending crewed and uncrewed platforms.

Healey also announced the winners of the 2025 AUKUS Maritime Innovation Challenge, focused on the command, control and teaming of undersea systems. Three of the four winning suppliers are UK based: Decision Analysis Services Ltd, an SME based in Basingstoke; SEA Ltd, a large enterprise based in Frome; and A-2i, a micro-consultancy based in Dorchester, Dorset. The fourth winner is MSI Transducers, a large enterprise based near Boston, USA. Each company will receive a share of £3 million in funding to develop and test their capabilities.

The ministers also announced progress in establishing Submarine Rotational Force-West, which will see a rotational presence of UK and US nuclear-powered submarines at HMAS Stirling in Australia. The first rotation of a US nuclear-powered submarine to the Australian base is expected in 2027, followed by a UK Astute class boat. This follows the first successful submarine maintenance period conducted on a UK Astute class submarine at HMAS Stirling earlier this year.

Under AUKUS, Pillar 1 focuses on Australia’s acquisition of conventionally armed nuclear-powered submarines, while Pillar 2 pools the defence sectors of all three nations to develop advanced military capabilities. The announcements build on the Geelong Treaty signed in July 2025, which established the framework for what the government describes as the deepest level of bilateral UK-Australian defence cooperation in generations.