15th September 2026 marks five years since the announcement of the AUKUS trilateral defence partnership between Australia, the United Kingdom (UK), and the United States (US). Initially designed to provide Australia with a fleet of next-generation nuclear-powered attack submarines (SSNs) and update the Royal Navy’s SSN fleet, AUKUS has since expanded to encompass further defence innovation – including uncrewed systems, quantum technology, and Artificial Intelligence (AI) integration.
Since its inception, AUKUS has achieved major milestones, such as the establishment of the Australian Submarine Agency (ASA) in July 2023 and the announcement of the first Signature Project under Pillar II in May 2026. This week’s Big Ask builds on these successes, asking ten experts: What has been the most significant achievement of AUKUS in the past five years?
Professor of International Security and Co-Director of Security Research Institute, Lancaster University, and Visiting Fellow, Royal Navy Strategic Studies Centre
AUKUS’ most significant achievement has been to institutionalise ‘collective seapower’ among Australia, the UK, and the US, turning strategic alignment into an enduring framework for practical cooperation. Its importance lies less in the capabilities delivered so far than in establishing the political, technological, and industrial foundations from which seapower can collectively be generated over several decades.
AUKUS goes beyond interoperability among three navies. It progressively connects defence industrial bases, technological ecosystems, maintenance arrangements, skilled workforces, and strategic planning. This represents a new model of forward-looking alliance: advanced military capability is produced collectively, rather than developed nationally and coordinated afterwards. Such managed interdependence does not diminish sovereignty; it gives each partner capabilities, resilience, and strategic reach that could hardly be generated alone.
The submarine programme is central, but its significance is also institutional. Its long timescale binds the partners across electoral cycles and makes sustained cooperation strategically necessary. Pillar II reinforces this whole-system logic by connecting submarines with AI, autonomy, cyber, quantum technologies, and undersea systems. AUKUS thereby translates the idea of a free and open Indo-Pacific into an enduring capacity for the collective upholding of the maritime order in the longer term.
This achievement should not be overstated. Political ambition has advanced faster than shipyard capacity, workforce development, and submarine production. Yet, judging AUKUS only by platforms already delivered misses its novelty. Its real test is whether these collective arrangements become credible, resilient, and, most importantly, durable. The three nations are not there yet, but AUKUS has already begun transforming allied maritime cooperation into the collective production of enduring seapower.
Adjunct Fellow, Council on Geostrategy, and Expert Associate, Australian National Security College
The biggest achievement of AUKUS since its formation in September 2021 has been to integrate the defence industrial and technology bases of Australia, the UK, and the US in an ambitious, long-term, and strategically relevant capability development project. This alone was worth the effort, despite the associated stresses and the frustratingly long timeline before AUKUS will start delivering a new class of SSNs for the Australian and British navies, as well as other common military capabilities for all three partners.
As a counterbalancing measure principally in reaction to the People’s Republic of China’s (PRC) breathtaking military buildup, AUKUS was overdue even five years ago. Since then, the axis of cooperation between the PRC, Russia, and other revisionist powers has only tightened. The fact that AUKUS has survived changes of government in all three partner countries is its greatest political achievement.
In today’s more politically disaggregated environment, among the US and allies it would be difficult – if not impossible – to get an initiative like AUKUS off the ground. Its survival shows that it has passed the national interest test in all three capitals, despite encountering partisan frictions in America and Australia, although markedly less so in the UK.
AUKUS strongly supports the logic that alliances are and will remain force multipliers, notwithstanding significant differences in scale and strategic circumstances among the tripartite partners.
International Fellow, Council on Geostrategy, and Senior Vice President of National Security and Intelligence Programmes, Centre for the Study of the Presidency and Congress
In Dune: Part One, the film adaptation of the first of Frank Herbert’s book series, the Reverend Mother Gaius Helen Mohiam says ‘our plans are measured in centuries’. While AUKUS’ time horizon is markedly shorter than that of the Bene Gesserit, viewing its successes requires a much broader perspective than merely its first five years.
AUKUS is a framework for long-term strategic cooperation that will reshape the Indo-Pacific and cooperation among Canberra, London, and Washington. AUKUS survived reviews in all three countries, each of which had markedly different political environments, thus demonstrating the allied commitment to this framework.
This commitment will likely continue given the importance of AUKUS to the interests of each country individually and all three collectively, regardless of changes in government. It cannot be taken for granted, and further political capital is needed, but the auguries are positive.
Practically, AUKUS has seen considerable investment in Australia’s naval infrastructure, laying the foundation for hosting, maintenance, and berthing of SSNs via Pillar I. In parallel, it has seen significant upgrades to Canberra’s ability to operate nuclear reactors – itself a long-term investment. This will enable nuclear-powered submarines from all three navies to operate much further and longer across the Indo-Pacific and challenge the PRC’s maritime and territorial ambitions.
Less headline-grabbing, yet arguably as important, the reduction of International Traffic in Arms Regulations (ITAR) barriers has dramatically improved defence industrial cooperation and interaction. These rules, while necessary in broad practice, have stood in the way of cooperation among allies (who already share the most sensitive information and intelligence bilaterally and as part of the Five Eyes) and are now steadily being removed. Additional progress and momentum are necessary, but the trajectory is positive.
Work is now needed for better operationalising of Pillar II – technological cooperation and development. Pillar II was initially a bit of a catch-all for future technologies, with little clarity on what it was designed to develop. Now though, the transition towards the development of desired effects is driving the acquisition of and investment in key technologies, and marks a positive development.
International Fellow, Council on Geostrategy; Founder and Principal, Barrier Strategic Advisory; Adjunct Fellow in Naval Studies, UNSW Canberra; and Expert Associate, ANU National Security College
The most significant achievement of AUKUS over the past five years has been its political resilience. Despite the ambition, cost, and risks associated with the partnership, AUKUS remains largely on track, particularly its main effort under Pillar I: Australia’s acquisition of SSNs.
That resilience is significant because all three countries have experienced substantial political change since AUKUS was announced in September 2021. Eight months after the announcement, Australia changed government from the Coalition to Labour. Yet, the government of Anthony Albanese, Prime Minister of Australia, not only retained AUKUS, but has made it central to Australian defence policy.
The US has also undergone a significant political shift. Donald Trump’s return to the presidency in 2025 brought a much more transactional approach to alliances and renewed scrutiny of American commitments. However, its review of AUKUS reaffirmed support for the partnership, with the administration declaring it ‘full steam ahead’.
The UK has moved from a Conservative to a Labour government and has had five prime ministers since AUKUS was announced. Despite political instability, serious pressures on defence spending, and challenges within its submarine industrial base, successive governments have continued to support AUKUS.
AUKUS’ greatest achievement, then, is that political support has endured across three very different political systems and significant changes of government. That suggests something important: each country increasingly sees AUKUS not simply as a partnership that harks back to old relationships, but as being firmly in its own national interest. That political foundation makes AUKUS more likely to withstand the considerable challenges still ahead.
Co-President (Research), Council on Geostrategy
While AUKUS is frequently understood to be a submarine pact or technological accelerator – Pillar I and Pillar II – its most important initial achievement has been conceptual. Over the last five years, it has redefined the mental map through which we see the world. It does this in several ways: firstly, it binds the Euro-Atlantic and the Indo-Pacific together in a way that did not exist prior to the agreement; secondly, it scotches the narrative of Britain’s decline after Brexit; and thirdly, it re-centres Australia in British and American strategic discourse.
By binding Canberra, London, and Washington into a shared defence industrial and geopolitical ecosystem, AUKUS dismantled the idea that the Euro-Atlantic and the Indo-Pacific exist in isolation – even before Russia’s full-scale invasion of Ukraine drew Indo-Pacific actors (the PRC, Iran, and North Korea) into a war on European soil. As AUKUS will provide the Royal Navy with more nuclear submarines, it also becomes central to the North Atlantic Treaty Organisation’s (NATO) position in the Euro-Atlantic.
Moreover, AUKUS came at the right time: it undermined the inaccurate narrative of the UK’s decline that emerged after Brexit. It proved that the UK was not turning inward – or isolationist – but was undergoing a period of strategic renewal. Those critics who foresaw a diminished and regionally bound Britain could not overlook the fact that London was now co-leading the most consequential defence framework of the 21st century.
More than that, it has created a stronger alignment between the UK and Australia. This relationship had been undergoing a renaissance since the 2013 defence and security treaty between the two nations, as well as the Australian decision to procure Type 26 frigates. Yet, AUKUS takes the relationship to new heights: Australia is becoming part of, and strengthening, Britain’s defence-industrial base. It therefore becomes evermore central to the UK’s interests.
True, it will take many more years for pillars I and II to come to fruition. However, the intellectual marker has been laid down. AUKUS has already reshaped the geopolitical imaginary, ended the notion that the Euro-Atlantic and the Indo-Pacific are distinct, and affirmed that Britain remains a premier guarantor of international security.
Professor of History, Chair of the History Department, and Director of the Heritage Studies PhD Programme, Arkansas State University
Looking at the AUKUS agreement from the US Navy’s perspective, one of the most important achievements was the development of forward submarine access and basing in Western Australia. This will allow for better naval force projection in the Pacific though quicker sustainment turnaround and deterrence posture.
In November 2025, the Virginia class attack submarine USS Vermont completed the second submarine maintenance period at HMAS Stirling. This operation showed that the US Navy could sustain a forward-deployed nuclear attack boat on Australian soil. Building on this success, the three nations of AUKUS finalised an agreement to establish Submarine Rotational Force-West (SRF-West) at HMAS Stirling by 2027.
In May 2026, the partners also set the deployment framework for American Virginia class submarines in Western Australia and streamlined Australia’s path to acquiring three Virginia class boats, which will boost the Royal Australian Navy’s abilities in the region. For the US Navy, this new base is not primarily about helping to develop the Royal Australian Navy, it is about a new forward-basing node much closer to contested Indo-Pacific waters than Guam or Hawaii.
Adm. Daryl Caudle, Chief of Naval Operations of the US Navy, called AUKUS ‘one of the most significant strategic undertakings in the history of the submarine force’. However, one caveat to this new plan is the lag in US Navy production of submarines. Virginia class production will need to be nearly doubled to 2.33 boats per year to cover both American and Australian requirements, but pace has slowed to 1.1 per year, resulting in unfulfilled promises for AUKUS.
Adjunct Fellow, Council on Geostrategy; and independent defence analyst, writer, and illustrator
AUKUS leads the way to a stronger and more interoperable force, bringing the UK’s ally and trusted friend Australia into the privileged and advantaged nuclear submarine community. The AUKUS submarines, constructed in British yards, will advance the country’s tradition of building top-tier naval capabilities.
Yet, while headlines and politics largely focus on large submarines, a huge part of the promise resides under Pillar II. Solid investment in quantum navigation and communication, uncrewed underwater platforms, cyber, and other key technologies is a clear net positive for British industry. These capabilities are vital for the three partner countries’ shared future.
As with any major initiative, there are areas that warrant close attention. Much of the discussion has understandably focused on timelines and uncertainties, but there is a less visible strategic risk worth highlighting. The momentum and priority attached to Pillar II should not inadvertently crowd out smaller, promising projects that have merit in their own right, and which may be important to pursue regardless of how the wider initiative develops. As the UK looks ahead, it should ensure that the scale of the investment agenda does not mean that it loses sight of the ‘defence’ in defence investment.
Minister of State for the Indo-Pacific (2022-2024), and Minister of State for the Armed Forces (2019-2020)
During the Covid-19 pandemic, calls took place between British and Australian naval and defence department leaders to test whether the UK would be up for the greatest giant of a challenge – to allow Australia to join the family of two (Britain and America) in their nuclear-powered submarine enterprise.
The world was changing. Australian perspectives on its responsibilities to protect and maintain open waterways was increasing, and major powers were not playing nice anymore. Maritime freedom of navigation, the lifeblood of global trade and for all our economic security, was starting to be under strain.
Remember that the AUKUS project was begun before Russia invaded Ukraine. Prescient, perhaps.
So, is this vision and grand ask working out today? Well, the most complex web of new Australian nuclear-capable legislation has been achieved, the US has unlocked vast swathes of historic ITAR limitations, and the UK has committed vast resources to the renewal and growth of its existing nuclear enterprise in order to underpin Australia’s new long-term boat programme.
The social licence to turn Australia into a nuclear nation seemed like one of the greatest hurdles, but as global stability teeters, the Australians have demonstrated their usual pragmatism for standing up to threats. Britons and Americans have leaned in, altruistically as well as with clear-eyed effort, to strengthen their own enterprises and create resilience for the existing SSN fleets.
The investment numbers seem vast, but they stretch over decades, and bring the deepest and most effective deterrent to those who would wish to disrupt or stop maritime freedom of navigation. A resilient maritime environment is vital to economic security.
The AUKUS vision those forward-thinking naval leaders presented is now operational reality across two lines of effort: Pillar I (the submarines) and Pillar II (bringing together naval and industrial innovators to work easily together on project designs to provide asymmetric advantage to the UK and its allies).
Let us be under no illusion how difficult it is to work across three nations and to trust and intertwine beyond even historic wartime efforts – at industrial, doctrinal, financial, and skills development levels and depth beyond even what those determined military leaders could imagine.
The AUKUS trilateral commitment has survived changes of government and political colour across all three countries. Allies and neighbours initially nervous now quietly champion the resilience and protections that they will benefit from, and those who would wish democratic nations determined to protect freedom for their citizens harm are clearer than ever that the AUKUS nations stand firmly together.
International Fellow, Council on Geostrategy, and Research Assistant, University of Western Australia Defence and Security Institute
One of the most significant achievements of AUKUS in the past five years is the progress made towards the operationalisation of SRF-West through the upgrading of HMAS Stirling in Perth and upskilling of Royal Australian Navy personnel there. AUKUS’ first five years have not been without adjustment, controversy, and the perennial need for media firefighting. However, since the announcement of the Optimal Pathway in March 2023, developments at HMAS Stirling have occurred at pace and, importantly, more or less on schedule.
The significance of this stems firstly from Western Australia’s expanded defence ecosystem and architecture. Australian personnel have now assisted in the maintenance of both a British and American SSN at HMAS Stirling, a demonstration of both the technical expertise acquired by Royal Australian Navy personnel and enhanced capacity of the base through AUKUS-related investment. In June 2026, Washington re-established US Submarine Squadron 3, which will operate out of HMAS Stirling, and the Naval Support Activity Stirling, which will support American servicepeople, their families, and contractors rotating through Perth. Indeed, US personnel are already migrating to Western Australia and beginning work at HMAS Stirling.
SRF-West operations are set to commence in December 2027, with the original estimate being ‘as early as 2027’. This relatively consistent timeline for operations, and probable fulfilment of it points to the other significant factor of HMAS Stirling developments: the likely completion and operationalisation of a significant AUKUS landmark as scheduled.
The ability for such a large, cross-hemisphere defence industrial partnership to run into delays is a drum regularly beat by critics, and is indeed a complication with a project of this scale. However, the developments at HMAS Stirling point to the timely fulfilment of one of the more significant steps for Australia in acquiring and operating SSNs – arguably the trilateral’s main goal.
Member, House of Lords, and Officer, AUKUS All-Party Parliamentary Group (APPG)
Five years ago, the AUKUS agreement was received with surprise, hope, and scepticism in equal measure. While there is still much to do to realise the full potential of the landmark trilateral, nobody can doubt the determination of the AUKUS nations to deliver a step-change in the collective national security of free and open nations.
Next year in Barrow-in-Furness, workers will cut steel on the first SSN-AUKUS submarine. That is a formidable achievement. In five years, three governments have agreed on a common design; aligned export controls and nuclear stewardship rules; committed billions to shipyards in Barrow, Derby, and Adelaide; and begun building reactors for a class of boat that did not exist on paper in 2021. This programme is on schedule to begin construction on the timetable set out at the start. Nobody should underestimate what that represents.
Yet, the submarines are the bedrock in AUKUS’ biggest achievement – the fact of binding together three democracies, spanning the Euro-Atlantic and the Indo-Pacific, in a commitment that will outlast the administrations that signed it and those that have succeeded them. It has survived changes of leadership in all three capitals. It has created the deepest technology sharing arrangement between allies since the Second World War. Above all, it has restored a sense that liberal democracies with shared values are capable of acting together, at scale and over decades, to deter those who would coerce them.
Authoritarian states are rising and testing the resolve of the free world. AUKUS is part of the answer to this. It may yet define the geopolitics of the century ahead.
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