# AUKUS > Australia-UK-US trilateral security partnership built around nuclear-powered submarines and advanced technology sharing, reshaping Indo-Pacific defence alignment since 2021. **Meta:** type: reference · date: 2026-07-03 · heads: · 3 takes · 2 lenses · 2 regions ## What it is AUKUS is a trilateral security partnership between Australia, the United Kingdom, and the United States, announced on 15 September 2021. It operates through two pillars. Pillar I commits Australia to operating a fleet of conventionally-armed, nuclear-powered attack submarines (SSNs) built and sustained with US and UK technology, filling a capability gap that conventional diesel-electric submarines cannot address in the Indo-Pacific's long ocean distances. Pillar II is a rolling programme of joint advanced-capability development covering artificial intelligence and autonomy, quantum technologies, advanced cyber, hypersonic and counter-hypersonic weapons, electronic warfare, and undersea systems. Neither pillar involves nuclear weapons; Australia's Nuclear Non-Proliferation Treaty obligations are unchanged. ## History US President Joe Biden, UK Prime Minister Boris Johnson, and Australian Prime Minister Scott Morrison announced the partnership in September 2021, simultaneously cancelling Australia's A$90 billion contract with France's Naval Group for conventionally-powered submarines. France recalled its ambassadors from Washington and Canberra in protest, a diplomatic breach not fully repaired until 2023. The March 2023 "Optimal Pathway", announced by Morrison's successor Anthony Albanese at a San Diego trilateral summit alongside Biden and UK Prime Minister Rishi Sunak, set the sequencing: a Submarine Rotational Force-West (SRF-West) of US and UK SSNs at HMAS Stirling in Western Australia from 2027; transfer of three to five in-service Virginia-class SSNs to the Royal Australian Navy in the early 2030s; and a new jointly-designed SSN-AUKUS class entering UK Royal Navy service in the late 2030s and the RAN in the early 2040s. The UK committed £6 billion in 2025 to SSN-AUKUS design and delivery, with BAE Systems and Rolls-Royce as lead contractors. Australia's Parliamentary Budget Office has estimated the full programme cost at approximately A$368 billion through 2054-55, making it the largest defence undertaking in Australian history. ## Current state As of mid-2026, AUKUS has shifted from architecture to construction. At the [30 May 2026 Defence Ministers' Meeting in Singapore](/en/n/albanese-aukus-singapore-virginia-subs), Australia, the US, and the UK settled on three in-service Block IV Virginia-class submarines as the acquisition path, dropping an earlier mixed new-and-used plan to simplify crew training and maintenance logistics. Australia's Deputy Prime Minister Richard Marles met US War Secretary Pete Hegseth and UK Defence Secretary John Healey to finalise the agreement. US Navy support elements began rotating to HMAS Stirling, with SRF-West establishment confirmed for 2027. Australia has committed A$8 billion for SRF-West infrastructure, A$3.9 billion for a submarine construction yard in South Australia, and A$12 billion for the Henderson Defence Precinct in Western Australia. In February 2026, HMS Anson became the first Astute-class submarine to complete a port visit to Australia under SRF-West arrangements. The 30 May meeting also launched the first Pillar II Signature Project: joint development of payloads and enabling systems for unmanned undersea vehicles (UUVs), with initial deliveries targeted for 2027. ## Relationships AUKUS sits inside a web of interlocking US-led Indo-Pacific security architecture alongside the Quad (US, Japan, Australia, India) and US bilateral alliances with Japan and South Korea. China has consistently condemned the partnership as Cold War thinking and lodged formal objections to Australia's acquisition of nuclear-propulsion technology, arguing it violates the spirit of non-proliferation norms. The June 2026 [Nakamal Agreement](/en/n/australia-vanuatu-nakamal-jun29) between Australia and Vanuatu, which bans foreign military infrastructure in Vanuatu in exchange for A$500 million over a decade, illustrates the broader Pacific contest AUKUS sits within. [China's Foreign Ministry](/en/n/china-vanuatu-australia-reaction-jun30) responded by accusing Canberra of "geopolitical games," framing AUKUS and Australian Pacific diplomacy as a coordinated containment strategy. The partnership also functions as a defence-industry integration mechanism: the 30 May 2026 ministerial expanded the licence-free technology environment among the three countries, building on the Australia-UK Defence Industry Dialogue revived in February 2026. ## What to watch - Delivery of the three Virginia-class submarines and whether US Navy production constraints, running below the two-boats-per-year target, push the early-2030s transfer window. - Progress on the SSN-AUKUS design programme and the first UK boat, which must enter Royal Navy service before Australia's own SSN-AUKUS hulls can follow. - Scope and partners for additional Pillar II Signature Projects beyond UUV payloads, and which allied nations are brought into the widening technology-sharing environment. - Parliamentary cost scrutiny in Australia as A$368 billion lifecycle estimates appear in successive budgets and the programme ramp accelerates. ## Regional takes (batched by bias / lens) ### official record - **UK Government** (United Kingdom, en) — Joint statement from the 30 May 2026 AUKUS Defence Ministers' Meeting in Singapore, confirming three in-service Virginia-class submarines for Australia and the launch of the first Pillar II Signature Project on unmanned undersea vehicle payloads. Source: https://www.gov.uk/government/publications/aukus-defence-ministerial-joint-statement-30-may-2026/aukus-defence-ministerial-joint-statement-30-may-2026 - **US Department of War** (United States, en) — US Department of War spotlight page documenting the American commitment to AUKUS, covering Pillar I submarine transfers and Pillar II advanced-capabilities collaboration. Source: https://www.war.gov/Spotlights/AUKUS/ ### parliamentary analysis - **UK House of Commons Library** (United Kingdom, en) — House of Commons Library research briefing on AUKUS covering the partnership's formation, the optimal pathway timeline, UK cost commitments, and parliamentary scrutiny of the programme. Source: https://commonslibrary.parliament.uk/research-briefings/cbp-9335/ ## Across the graph - Related: [[china-vanuatu-australia-reaction-jun30]], [[australia-vanuatu-nakamal-jun29]], [[albanese-aukus-singapore-virginia-subs]] - Entities: Aukus, Australia, United States, United Kingdom, Person:anthony Albanese, Richard Marles --- Canonical: https://rbtfl.xyz/en/n/aukus-dossier