Why is Australia buying used submarines? A naval expert answers key AUKUS questions

Following the recent announcement that Australia would acquire three submarines already in US service rather than two used submarines and one new one, AUKUS has again dominated headlines. AUKUS is a defence capability agreement between the United States, the United Kingdom and Australia. Since it was announced in 2021, it’s rarely been out of the news. But how much of what you have heard is true? As a former Navy officer specialising in anti-submarine warfare, I am frequently asked the same questions about AUKUS. While I can’t address everything in one article, here are the details behind some of the most common claims. Why is Australia buying used submarines? Australia has Collins class submarines that entered service between 1996 and 2003. Work should already be underway to replace them, but decades of delays and underfunding have left us with an ageing fleet. Though the Collins class submarines will each go through a multi-year maintenance period extending their life, they won’t last long enough. They will need to be decommissioned before Australia can co-design, build and produce submarines here under AUKUS. A stopgap solution is required. The purchase of three Virginia class submarines in 2032, 2035 and 2038 will provide this, and also give Australia the ability to start operating nuclear-powered submarines. Think of it as a “crawl, walk, run” approach. The Virginias are the walk phase before we start building our own nuclear-powered submarines. Acquiring submarines already in service reduces risk and complexity, avoids the challenges of introducing a new submarine, and removes the need for initial certification trials. Is Australia getting a less capable submarine? Not in any meaningful sense, though the third Virginia will be an older version than planned, so its sensors will probably be slightly less capable. Australia will now receive three Block IV Virginia class submarines. These remain among the most capable attack submarines in the world. They carry more than 20 torpedoes and 12 Tomahawk land strike missiles. Much of the commentary this week has suggested Australia has lost additional missile capacity because the submarines we’re receiving won’t have the “ Virginia Payload Module ” – a new hull section that allows the submarines to carry more missiles. But that commentary is incorrect. The submarine Australia was expected to receive in 2038 was never intended to have that capability. In conflict, Australia would predominantly use these submarines in an anti-submarine and anti-ship role. Land strike missiles are not used for this and so the extra capacity isn’t essential. It’s also capability the US has said it is not willing to provide . The main difference is the third submarine will have fewer years of life remaining than a new boat. A Virginia class submarine off the production line would normally have a 33-year life . At Senate estimates this week, the Australian Submarine Agency said each boat will have more than 20 years of life remaining when we receive them. Claims these submarines would only have eight years of life do not withstand scrutiny. The kind of submarines Australia will receive only started entering service in 2020 . Are we paying $368 billion for three used submarines? The figure most often quoted for AUKUS is $368 billion. While technically correct, this figure covers costs through to 2055 including infrastructure, workforce and maintenance costs over 31 years, plus the purchase of Virginia class submarines to Australia and building our own submarines. Of the total, about $244 billion is the projected cost, while the remaining $122.9 billion is a 50% contingency on top. This is money set aside to cover risks, cost growth and unforeseen problems. Most defence projects carry 5–10% contingency. The Department of Defence’s 2026 Integrated Investment Program states nuclear-powered submarines will cost between $71 billion and $96 billion over the next decade. Against projected defence funding of about $887 billion over the same period, this equates to around 8–11% of defence spending. Read more: In view of Trump’s review of AUKUS, should Australia cancel the subs deal? We asked 5 experts Can the US build enough submarines for Australia? This is one of the most legitimate points of debate in the discussion. The US reduced its production rate of submarines after the Cold War. Since 2011 it has set a goal of increasing its build rate to two submarines a year. From 2016–19 it averaged 1.9 boats a year. According to the US Congressional Research report on Virginia class submarines, this build rate dropped off due to workforce issues during COVID and challenges associated with moving to the build of the new Block V submarine, which is 2,000 tonnes larger than the Block IV Virginia. The US is investing billions of dollars into its submarine industrial base to address this issue. In May ,