The Royal Australian Navy will acquire at least eight nuclear boats, based on a British or American model, to replace the retiring conventionally powered Collins-class submarines.
The details of the largest defence deal in Australia's history will be announced within weeks.
Outgoing ambassador to Washington Arthur Sinodinos said the AUKUS alliance between Australia, the US and UK showed Canberra was serious about engaging with allies.
"For Australia, this is a moonshot. This is a whole-of-nation effort," he told the Centre for Strategic and International Studies.
"We're about to stand up and put our money where our mouth is in a huge way."
Mr Sinodinos said co-operation between the US and Australia on advanced and nuclear technologies had become "a state of mind".
"People will see the habits of co-operation, sharing information, interchangeable industrial bases, are going to be a very substantial long-term benefit," he said.
"The very fact the Americans are prepared to share their crown jewels with us implies there will have to be progress on the seamless transfer of technology."
Australia promised Britain and the United States it would keep their military secrets safe, which Defence Minister Richard Marles said was crucial to clinching the deal.
"It does involve a really significant hardening of security in a physical sense with buildings and fences and the like, but also in an IT sense, around the information which goes with that," Mr Marles said.
"There is a high degree of confidence within both the United States and the United Kingdom about Australia's ability to do that."
Former prime minister Scott Morrison, who negotiated the AUKUS alliance, said the agreement was never about buying off-the-shelf submarines.
"We were going for the synergy outcome here and what that meant was we wanted more, in total, between all three countries," he told the Meridian100 podcast.
"More nuclear-powered submarines built, not the same amount just moved around."
with Reuters
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