In a press conference on Thursday morning, the three nations announced the agreement, which they named AUKUS, as a partnership that will enable Australia to have nuclear-powered submarines in its possession for the first time.
The U-K and U-S's involvement will mean that Australia will gain access to the technology needed to construct its own fleet.
Prime Minister Scott Morrison says construction of the new submarines will stay in Australia.
"This will include an intense examination of what we need to do to exercise our nuclear stewardship responsibilities here in Australia. We intend to build these submarines in Adelaide, Australia, in close cooperation with the United Kingdom and the United States. But let me be clear - Australia is not seeking to acquire nuclear weapons or establish a civil nuclear capability. And we will continue to meet all of our nuclear non-proliferation obligations."
US President Biden says the alliance was also about recognising the imperative of ensuring peace and stability in the Indo-Pacific over the long-term.
There was no mention of China in the virtual press conference as the plan was unveiled, but the new security alliance is likely to be seen as a provocative move to Beijing.
Nuclear power will allow Australian attack submarines to remain at sea for as long as five months and operate more quietly than the country’s existing Collins class diesel powered vessels.
