An Australian Collins-class submarine, HMAS Sheean , arrives for a logistics port visit in Hobart. The class is expected to be retired closer to 2040, when Australia is expected to operate its nuclear-powered boats. (Australian Defence Force via Get)

The leaders of Australia, the UK, and the US have unveiled a phased ‘Optimised Pathway’ that will equip Canberra with two nuclear-powered submarine (SSN) classes over the next two decades.

Australian Prime Minister Anthony Albanese has described the move, which was unveiled on 13 March at a San Diego meeting attended by the three leaders, as “the country’s biggest-ever investment in its defence capabilities”. The meeting was held as part of efforts to progress the AUKUSsecurity partnership, which was first announced in September 2021.

The initial phase of this pathway will begin later in 2023 when the US increases the number of its SSN visits to Australian ports. In these visits, Australian sailors will join US crews for training and development. The UK will increase port visits to Australia from 2026.