AUKUS is the biggest defence project in Australia’s history. Here’s what the pact between Australia, the UK and the U.S. involves, how Australia plans to get nuclear-powered submarines, and why it remains controversial.
AUKUS was announced in September 2021 by the leaders of Australia, the United Kingdom and the United States. Its name comes from the first letters of the three countries.
The pact is widely seen as a response to China’s growing military power in the Indo-Pacific, although the three countries describe it as supporting a stable and open region.
Announcing AUKUS meant Australia scrapped a deal with France to build conventionally powered submarines, which caused a major diplomatic rift with Paris.
The submarine plan
Nuclear-powered submarines can stay underwater for months, travel faster and further, and are much harder to detect than diesel-powered submarines. Only a handful of countries have them. They are nuclear-powered, but won’t carry nuclear weapons.
Under the plan announced in 2023, U.S. and UK submarines will rotate through HMAS Stirling, near Perth, from 2027.
From 2032, the U.S. is expected to sell Australia at least three Virginia-class submarines, with the option of two more. Later, Australia and the UK will build a new class of submarine, called SSN-AUKUS, with the first Australian-built boats in Adelaide expected in the early 2040s.
The Government estimates the submarine program will cost between $268 billion and $368 billion to the mid-2050s, including a new shipyard in Adelaide and thousands of jobs.
In 2025, the Trump administration reviewed AUKUS, and the Pentagon later confirmed its support for the deal.
Pillar two
AUKUS also has a second pillar, focused on advanced military technology. The three countries are working together on areas including artificial intelligence, hypersonic weapons, quantum technology, cyber security and undersea drones.
The debate
Supporters say AUKUS gives Australia a powerful deterrent, deepens its alliance with the U.S. and the UK, and builds a high-tech defence industry.
Critics, including some former prime ministers, argue it costs too much, ties Australia too closely to U.S. military plans, and risks Australia’s sovereignty. There are also doubts about whether the U.S. can build enough submarines for its own navy and still sell some to Australia, and about safely managing nuclear waste.
Because the program spans decades and many governments in all three countries, its success will depend on sustained political support in Canberra, Washington and London.
