AUKUS is not just a submarine acquisition program; it is a long-term strategy for strengthening Australia’s agency in a contested Indo-Pacific, where undersea power matters more than ever. Undersea power is the national capacity to understand, monitor, protect and contest the undersea environment, including undersea cables, seabed resources, maritime energy infrastructure and more.
Geography imposes significant operational demands. Australia occupies an island continent separated from principal allies and partners by expanses of ocean, with ports spread far apart and sea lines of communication extending thousands of kilometres. Submarines form an integral part of the suite of defensive capabilities required to deter aggression and protect Australia’s expanded maritime interests.
Despite the distance, Australia is not immune to international conflicts and has repeatedly found itself engaged in them close to home and far from its shores. Along the way it has looked to acquire the best possible military capability available: the apex predator. For the navy of World War I, it was the battle cruiser HMAS Australia, and submarines were in the mix.
In the Pacific War, Cockburn Sound – a natural basin near Perth and the site of HMAS Stirling – housed about 50 Allied submarines. Up to 170 operated in and through the area, disrupting Imperial Japanese supply routes and making the Malacca Strait impassable. This forced Japanese supply onto alternative overland routes, including the Thai–Burma railway. The geography hasn’t changed much.
During and after the Cold War, Australia bought a series of submarines, from the Oberon class to the Collins class.
AUKUS is the latest phase in a longer five-phase strategic evolution of how Australia seeks to generate and exercise maritime military power commensurate with its geography and available technology.
Future crises will likely involve long distances, contested maritime environments and enhanced technological sophistication.
Under the surface, our oceans remain opaque. Some claim the end of the era of stealthy submarines is approaching due to a convergence of technologies that may make the seas transparent. But the disappearance of Malaysia Airlines flight MH370 in the southern Indian Ocean illustrates the enduring difficulty.
Submarine warfare is a game of cat and mouse. As detection technology improves, so does stealth technology. The ocean is vast, deep and acoustically chaotic. Even with advanced sensors, the ocean’s noise floor – biological, geological and climatic – creates natural camouflage that’s difficult to pierce consistently, especially against a target trying to hide. Indeed, transparency concerns haven’t slowed the building of nuclear attack submarines, notably by China.
Surface transparency is different. Today, an Australian conventional submarine is detectable due to decades of submarine pattern analysis; AI use in anomaly detection; and the proliferation of drones and low earth orbit Chinese satellites that can detect the bow wave of its breathing pipe, called a snort. Transiting from Perth to Darwin requires use of the snort a dozen or more times, exposing it above water to allow diesel engines to run and charge batteries. That surface loiter time is detectable to a degree that threatens survival in conflict. The way to circumvent this is to stay underwater. For Australia’s long transits, that requires nuclear propulsion.
Australia is committing a large sum over 30 years to the AUKUS program. But kept in perspective, A$368 billion divided over 30 years would be A$12.3 billion per year, or one fifth of the estimated A$60 billion to be spent by Defence in 2026–27. Even A$12.3 billion should be a manageable fraction of the A$770 billion estimated federal expenditure this year – about 1.597 percent of its budget. Effectively, AUKUS is an insurance premium.
AUKUS also represents a transition from interoperability to interdependence in selected areas of advanced defence capability where Australia would struggle to go it alone. The Submarine Rotation Force – West (SRF-West), based in Cockburn Sound and operating US Virginia-class submarines, is the clearest manifestation of that today. SRF-West is key to the plan developed to overcome decades of Australian indecision, budget constraints and flip-flopping. Properly managed, though, this interdependence strengthens rather than diminishes Australia’s strategic position as it increases access to technologies, industrial opportunities and scientific collaboration that would otherwise be out of reach.
By the mid-2030s, the test will be whether Australia has the national systems, people, infrastructure and industrial capacity required to make and implement its own decisions to exercise undersea power.
None of this requires self-sufficiency. Even the United States relies on allied industrial capacity across multiple sectors. The objective is resilient sovereignty within an interdependent alliance network, not autarky.
But the submarines still have to arrive. They are the operational centrepiece of the AUKUS enterprise. Prolonged Australian indecision makes SRF-West a necessary measure, one that will bridge the gap until Australian sovereign submarine capability emerges.
The deeper question isn’t about complete self-sufficiency but whether Australia accrues greater capability to make sovereign decisions and the capacity to implement them, and whether it is better placed to shape its strategic environment than it would have been without AUKUS. If the trilateral cooperation produces those outcomes, AUKUS will have built not only submarines; it will have built Australian undersea power.
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