The underwater arms race
24th Jun 2026
The UK's BAE Systems is building Astute-class and Dreadnought-class submarines (image: BAE Systems)
The return of great-power rivalry, wars in Ukraine and the Middle East, rising tensions in the South China Sea and growing concern over seabed infrastructure have pushed undersea capability back to the centre of military planning. But this is not simply a contest of fleet numbers. The underwater arms race today is a structural transformation of the global maritime system, reshaping deterrence, intelligence gathering, seabed infrastructure protection and the balance of power across the Atlantic, the Indo-Pacific and the Arctic. As First Sea Lord General Sir Gwyn Jenkins told delegates at the Combined Naval Event in Farnborough in May 2026: “We are at a fork in the road, and the decisions we take now will have seismic and lasting consequences.”
After decades of relative underinvestment, major powers and emerging maritime nations are recapitalising underwater capability at a pace not seen since the Cold War. This renewal spans not only submarines but anti-submarine warfare systems, autonomous underwater vehicles, support fleets, seabed surveillance networks and the protection of critical underwater infrastructure. The geopolitical landscape is simultaneously reshaping procurement strategy, with intergovernmental collaboration, export partnerships and industrial allegiances all playing a pivotal role alongside raw capability.
A global competition
The scale of that competition is most visible in the contest between the United States and China. Despite long-standing plans to deliver two Virginia-class submarines per year, US output has struggled to exceed around 1.1 to 1.2 boats annually, constrained by workforce shortages, supply chain fragility and industrial bottlenecks. The Navy’s 30-year shipbuilding plan acknowledges a persistent gap between planned and achievable output, with workforce availability now the single largest constraint on recapitalisation. The US is simultaneously managing the Virginia-class attack submarine programme, the Columbia-class ballistic missile submarine programme and development work on the future SSN(X), placing extraordinary concurrent demands on a constrained industrial base.
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China, by contrast, is demonstrating the strategic advantages of scale, having launched 10 nuclear-powered submarines between 2021 and 2025, surpassing the US in both hull numbers and total launched displacement. Major expansion at Bohai Shipbuilding’s Huludao yard has enabled simultaneous production of the Type 093B and Type 094 classes, underpinned by vertically integrated supply chains, state-backed financing and a significantly larger skilled workforce. The strategic concern for Western planners is increasingly centred on industrial tempo, production resilience and fleet mass, rather than individual platform performance.
The contest extends well beyond two powers. Russia continues to prioritise its Borei and Yasen-M programmes despite sanctions and industrial constraints, with Arctic and North Atlantic operations the strategic focus.
France sustains two parallel nuclear programmes, the Suffren-class SSNs and the Le Triomphant-class SSBNs, while maintaining a strong export position through the Scorpene design. Germany and Sweden remain among the most technically influential conventional submarine designers, with ThyssenKrupp Marine Systems driving advances in air-independent propulsion (AIP) and low-signature construction through the Type 212CD, and Saab Kockums developing the A26 Blekinge class, which secured its first export customer in Poland in 2025.
India’s indigenous nuclear submarine programme has reached a significant milestone with the commissioning of INS Aridhaman in April 2026 and the fourth Arihant-class boat now in sea trials. South Korea has emerged as one of the most competitive builders in the world, with the KSS-III programme demonstrating a high degree of indigenous capability and Korean yards now in the final running for Canada’s US$40 billion submarine replacement programme.
For much of the post-Cold War period, Western navies prioritised small numbers of increasingly sophisticated platforms. That assumption is now being challenged by the realities of persistent maritime competition, Indo-Pacific scale, Atlantic and Arctic commitments, infrastructure protection requirements and sustained readiness demands. Capability alone is insufficient without industrial resilience, sustainment capacity and workforce depth.
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The AUKUS framework
As capability shifts from standalone platforms toward interoperability and integrated, distributed systems, more countries are taking a collaborative approach to construction and operation. The most significant example is AUKUS, the trilateral security partnership between Australia, the United Kingdom and the United States, designed to support Australia in acquiring its first conventionally armed, nuclear-powered submarine fleet amid growing tensions in the Asia-Pacific region.
Australia’s SSN-AUKUS boats will be based on the UK’s next-generation SSN Astute-class successor but incorporate technologies from all three nations, built in both the UK and Australia, with work scheduled to start by 2030. The first submarine is expected to enter service towards the end of the 2030s in the UK and the early 2040s in Australia, with both nations operating the class on a rotational basis under Submarine Rotational Force – West at HMAS Stirling near Perth.
The first significant US contract under AUKUS was awarded in late 2025, with Electric Boat securing US$196 million for engineering, technical and design-transfer work, marking a shift from political commitment to funded industrial delivery. In May, Babcock International announced a partnership with US defence prime HII to manufacture complex submarine components at its Rosyth facility in Scotland, relieving pressure on the US naval supply chain while reinforcing industrial integration under the framework.
Australian industry is now being drawn into the supply chain at scale. PMB Defence will partner with BAE Systems to integrate its advanced nickel zinc battery system into the SSN-AUKUS design and supply battery technology for other Royal Navy submarines. Nuclear propulsion will be delivered by Rolls-Royce, with the PWR3 reactor, designed for the UK’s Dreadnought class, expected to be adapted for SSN-AUKUS. Rolls-Royce has also signed a Memorandum of Understanding with the State of Victoria to develop Australia’s defence industry skills, supply chain and innovation ecosystem.
Astute and dreadnought
AUKUS has breathed new life into Britain’s naval shipbuilding. BAE Systems is running the Astute and Dreadnought programmes simultaneously at Barrow-in-Furness, where the workforce has grown to more than 16,000 people, compared to fewer than 10,000 a decade ago.
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The Astute class, a seven-boat fleet of 97m-long, 7,400-tonne displacement hunter-killers, is nearing completion. HMS Agamemnon, the sixth boat, completed a successful first dive in October 2025. To measure the centre of gravity during the trim and basin dive, 16tonnes of lead weights are brought onboard and moved side-to-side, measured using pendulums hung between decks, a method used by naval architects since the 1700s.
HMS Achilles, the final boat, is scheduled for commissioning in 2028. All boats are the first Royal Navy submarines designed entirely in 3D CAD and the first without optical periscopes, using high-specification video technology instead. Each carries Tomahawk Land Attack Cruise Missiles and Spearfish heavyweight torpedoes, powered by a Rolls-Royce PWR2 nuclear reactor with a 90-day dive endurance.
All four 153.6m-long, 17,200-tonne displacement Dreadnoughts, the new generation of SSBNs designed to replace the Vanguard class in the early 2030s, are at various stages of construction. First steel was cut on the fourth and final boat, King George VI, in September last year. Each is built in 16 units grouped into three mega-units to optimise the build timeframe, with a designed service life of 35 to 40 years, some 50% longer than the Vanguard class. Each boat is equipped to launch 12 Trident II D5 ballistic missiles and Spearfish torpedoes, powered by the PWR3 with reactor cores designed to operate for 20 years without refuelling and with 30% fewer parts than the PWR2. In January 2025, Rolls-Royce was awarded a £9 billion MoD contract covering research, design, manufacture and support of all nuclear reactors in Royal Navy submarines.
Nuclear stewardship and the balance of fleets
Nuclear stewardship is itself becoming a defining strategic capability, requiring reactor expertise, regulatory oversight, nuclear-certified supply chains, specialised dockyard infrastructure, waste handling, emergency preparedness and highly trained engineering workforces sustained over multiple generations. The UK, France, the United States, India, China and Russia all face similar long-term challenges in sustaining this at scale, and the burden is one reason why conventionally powered submarines remain strategically important.
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Advances in AIP, battery technology and quieting have made modern diesel-electric submarines exceptionally capable in littoral and regional operations. They are generally faster to build and allow greater fleet mass for nations seeking credible deterrence without the burden of a full nuclear enterprise. The continued export success of the Scorpene design and the growing competitiveness of South Korean and Japanese programmes partly reflects this calculus. Many nations are converging on mixed fleets that combine nuclear reach, conventional mass and autonomous persistence.
The evolving battlespace
The underwater battlespace now extends well beyond traditional submarine operations into hybrid warfare, persistent surveillance, cyber-enabled disruption and the protection of seabed infrastructure. The Nord Stream incident and subsequent European seabed security reviews have accelerated investment in distributed sensing, autonomous patrol systems and infrastructure monitoring. NATO’s establishment of a Critical Undersea Infrastructure Coordination Cell underlines the vulnerability of underwater cables, pipelines and distributed sensor networks, and governments across Europe and the Indo-Pacific are responding with dedicated investment in seabed domain awareness.
The rise of autonomous underwater systems is accelerating innovation while creating new engineering and assurance challenges, particularly where defence and commercial activity converge. Modern underwater platforms are becoming software-defined, digitally integrated systems that must remain adaptable across decades of technological change while operating in increasingly contested electromagnetic, cyber and acoustic environments. The disciplinary breadth required now spans naval architecture, software engineering, autonomy, nuclear engineering, systems engineering, hydrodynamics, acoustics, cyber security, advanced manufacturing, digital twin development and human factors.
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Workforce shortages are among the most acute strategic challenges facing the sector. Competition is intense globally for engineers, nuclear specialists, software developers and advanced manufacturing expertise. The Rolls-Royce and Siemens collaboration on the Dreadnought programme, sharing best practice across the digital landscape to enhance engineering, manufacturing, R&D, training and reactor operation, is one model for how industry is responding.
Global transformation
The real story of the underwater arms race is not a procurement narrative. It is a global transformation of the undersea domain, driven by industrial strategy, hybrid threats, workforce evolution, nuclear stewardship and the convergence of nuclear, conventional and autonomous capability. These are the forces that will shape the future of naval architecture and the wider maritime profession for decades to come.
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AUKUS STRENGTHENED WITH HMS ANSON SMP
A key milestone in the AUKUS collaboration was reached in February this year when HMS Anson docked at Western Australia’s HMAS Stirling for scheduled maintenance, representing the first time Australia had carried out work on a UK nuclear-powered submarine. Australian personnel worked alongside partners from the UK and the US on maintenance and familiarisation activities, building on experience gained from work on US Virginia-class submarines USS Vermont in 2025 and USS Hawaii in 2024. Participation in the UK Submarine Maintenance Period, ahead of the establishment of SRF-West at HMAS Stirling from 2027, will further build Australia’s familiarity with UK-designed submarines as the country prepares to begin construction of SSN-AUKUS in Adelaide by the end of the decade. |
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This article appeared in Submarines, TNA May/June 2026.