After a year and a half of negotiations with America and the United Kingdom, we finally have the current plan for how and when Australia will get its own nuclear-powered submarines.
The price tag has been described as "eye watering", and it'll be decades until they're all in the water.
Here's what we know about the AUKUS deal and what to expect.
What is AUKUS?
Before we dive into the actual deal, it might be helpful to do a quick recap.
AUKUS is the name for the security deal Australia, the UK and the US (A-UK-US) agreed to at the end of 2021.
The first, and so far the biggest, aspect of the pact is the submarine deal which is also called Pillar One.
Both of the UK and the US — which have nuclear-powered submarines — agreed to work with Australia and share plans for their subs so we could build our own.
The second AUKUS pillar will involve enhancing our defence capabilities with the help of the UK and US more broadly.
How many submarines are we getting?
In total, Australia will end up with eight of the new nuclear submarines, called SSN-AUKUS.
Those submarines will be based on a British design but have American technology or an American combat system.
While we wait for them to be built, though, Australia's federal government has struck a deal to take three Virginia-class submarines from the US early next decade.
They may be second-hand and it will need the approval of the US Congress to happen.
On top of that, the Australian government will also have the option to buy another two Virginia-class subs under the AUKUS pact.
So, in total: eight nuclear subs, three interim Virginia-class subs with the possibility of two more, means at least 11 submarines and, potentially, 13.
How much is the plan going to cost?
The current price tag for the entire submarines plan is between $268 billion and $368 billion over the next 30 years.
That includes $8 billion to upgrade the naval base HMAS Stirling in Western Australia as well as $2 billion over the next four years upgrading the Osborne shipyards in South Australia.
As part of its financial commitment, Australia will also be pitching in $3 billion over the next four years to production lines in both the US and UK, with the majority of the upgrade funds going to America.
The Australian Strategic Policy Institute's Justin Bassi says even though the price tag is "eye-watering", it's worth it.
"The alternative is an even heavier cost to Australia's security and sovereignty down the track," he said.
The government has acknowledged that the cost is significant, but it argues that — unlike other defence projects that have blown out in both costs and time — the nuclear sub will be different.
"[Firstly,] we announced very significant reforms to the procurement in October that will contribute to the performance of Defence," Defence Industry Minister Pat Conroy said.
"Secondly, as part of the announcement, we've announced a dedicated agency that will provide a laser-like focus on delivering the project.
"[Thirdly,] we've actually learned the lessons from past procure amendments, particularly [with] the Collins class."
When will the subs be delivered?
Five of the eight SSN-AUKUS nuclear-powered subs will be delivered by the middle of the 2050s, with the final three delivered in the 2060s.
The goal is to have one submarine built every two years from the early 2040s through to the late 2050s, to meet demand.
As for the Virginia-class submarines from the US to fill the gap in the meantime, the idea is to have them in the 2030s.
What rules are in place, given they’re nuclear-powered?
One of the other question marks over the subs deal is how it will work, given they are nuclear-powered but Australia has signed nuclear non-proliferation treaties and has no capability to process the fuel onshore.
We have a few more details now that reiterate that, firstly, Australia is not going to enrich uranium or reprocess any of the spent fuel as part of the deal.
We're also not producing any of the nuclear fuel and, instead, will source it from the UK and US in welded power units that will not need refuelling during the lifetime of the subs.
In case you're wondering if we could ever somehow use the fuel to then make nuclear weapons, the answer is no, not without more chemical processing which Australia doesn't have the facilities to do.
All three countries have been in close talks with the International Atomic Energy Agency (IAEA) about the subs to make sure they are happy with the oversight measures that will be in place.
"We've set the highest standards with the IAEA for verification and transparency, and we will honour each of our country's international obligations," President Biden said.
Defence Minister Richard Marles also confirmed that, in line with the treaty of Rarotonga, there would not be nuclear weapons aboard any of the SSN-AUKUS subs nor American submarines when they rotate through Australia.
However, he did flag that, by the 2050s, Australia would need to begin disposing of the nuclear reactors from some of the submarines and would need to have a facility established to do so safely.
"That facility will be remote from populations and today we're announcing that will be on Defence land, current or future," Mr Marles said.
What don't we know?
There's a few questions about the deal that will no doubt be answered and worked out in the coming years and decades.
One of the biggest ones for Australia is how the federal government plans to find and train the skilled workers needed to build, operate and maintain the submarines.
It is estimated the submarine project will support 20,000 jobs over the next 30 years and will require extensive training or upskilling of people.
Given we're already facing a worker shortage, increasing the demand for people could be a big ask.
There are also questions still about the level of oversight from the IAEA and how verification and transparency around how Australia is meeting its nuclear non-proliferation obligations will work.
