AUKUS Australia to buy U.S. nuclear submarines under AUKUS Australia has unveiled plans to buy up to five U.S. nuclear-powered submarines, then build a new model with U.S. and British technology under the ambitious plan to bulk up Western muscle across the Asia-Pacific in the face of a rising China. About AUKUS: AUKUS, is a trilateral security pact between Australia, the United Kingdom, and the United States. Announced on 15 September 2021 for the Indo-Pacific region. Under the pact, the US and the UK will assist Australia in acquiring nuclear-powered submarines.