Accelerating innovation, collaboration and delivery in undersea defence

In this guest article, Captain Adrian Pierce RN(Rtd) takes an overview of developments to secure the undersea battlespace.

Control of the seas has long provided significant advantages in times of peace and has been a decisive factor in many wars. In the modern world, over 80% of international trade moves by sea, 99% of digital data travels through undersea cables, and it is estimated that in excess of $10 trillion worth of financial transactions travel through these cables daily. The oceans therefore remain vital for economic security and so heavily influence Defence thinking.

As the world confronts the realities of 21st-century warfare, maintaining superiority at sea remains crucial, particularly as the West faces a complex myriad of hybrid warfare and grey zone attacks. Over the past couple of years, a spate of sabotage attacks against undersea cables, particularly in the Baltic Sea, have exposed the vulnerability of Europe’s undersea infrastructure.

In September 2022, Nord Stream 2 was blown up. In October 2023, Hong Kong-flagged Newnew Polar Bear dragged its anchor across the gas pipeline linking Estonia and Finland. At the end of 2024, Finnish authorities seized control of the Eagle S. vessel – believed to be part of Russia’s “shadow fleet” of tankers – which was suspected of damaging the Estlink 2 power cable and four internet cables between Finland and Estonia on Christmas Day. In a distinct change of approach, these vessels were publicly named, and action was taken by relevant governments. This approach continued when in January of this year, Defence Secretary John Healey announced the Royal Navy was tracking and responding to the Russian intelligence collection ship, the Yantar, as it passed through British waters for the second time in less than three months and loitered in the vicinity of Critical Underwater Infrastructure (CUI).

The increased targeting of CUI by adversaries as a tactic of hybrid warfare intended to destabilise societies presents a major security challenge. The unpredictable nature of such sabotage makes it an attractive tactic for sowing confusion and doubt, complicating Europe’s ability to mount a unified and decisive response.

Tackling these threats therefore requires a new approach. The upcoming Undersea Defence Technology (UDT) exhibition and conference, taking place from 25th to 27th March in Oslo, arrives at a critical time. Showcasing the latest advancements in undersea technology, the event serves as a key forum for stakeholders from the international naval community to engage in constructive discussions, shaping policies and strategies to strengthen undersea maritime security.

Standing strong against common threats

Despite significant challenges, 2025 is shaping up to be a year of strengthened cooperation among allies. From a push for greater alignment between NATO’s European members to cutting-edge defence technologies showcased at both DSEI Japan (May) and DSEI UK (September), this year will see the defence and security community come together in greater numbers from across the world. Protecting our maritime borders and critical undersea infrastructure requires the same approach. Building resilience and credible deterrence against such sabotage requires collaboration between armed forces, governments, and industry.

We are seeing greater recognition of this, with the UK-led 10-nation Joint Expeditionary Force (JEF), which recently activated Nordic Warden, a month-long advanced response option aimed at tracking potential threats to undersea infrastructure and monitoring Russia’s shadow fleet. This was immediately followed by the ongoing NATO initiative Baltic Sentry, led from JFC Brunssum in the Netherlands, and the announcement of TF-X Baltic, which will augment Baltic Sentry with a fleet of autonomous and uncrewed Vessels.

As nations step up to play a greater role in maritime defence, it is essential to emphasise a collective, unified, and decisive response while building resilience against such threats. Trade shows like UDT therefore serve as a valuable tool to bring together key stakeholders under one roof, allowing experts to share insights and collaborate on solutions.

Future defence technologies

As attacks against CUI look set to become a preferred tactic of hybrid warfare, the technologies and strategies designed to counter them must also evolve at pace. This will be a central topic during UDT, ensuring that the West and its allies develop the appropriate and effective technologies to build resilience against these threats.

As vulnerabilities in Europe’s CUI have been made increasingly clear, European nations have taken proactive steps to safeguard their maritime borders. Efforts have been made to increase the pace that damage to undersea cables is found and repaired. In 2024, the French Navy deployed an autonomous underwater vehicle capable of operating at depths of up to 6,000 metres below the ocean surface, while the UK announced the launch of two surveillance ships to support underwater operations, including undersea surveillance and cable protection. RFA Proteus, the first of the two ships, formally entered service in October 2023.

Yet advances in technology are not limited to the protection of CUI. Innovations in surveillance, data acquisition, architectures and automation can be seen throughout and across the underwater domain, as exemplified by the Royal Navy announcing Project CABOT. This plans to deliver remotely operated and autonomous ASW capabilities, built around the new Type 92 Sloop (an uncrewed surface vessel) and the Type 93 (a drone submarine), allowing the UK to pivot to a vision of “Digitalisation of the North Atlantic”. (More on project CABOT to come in a future article)

However, security in the maritime domain does not happen in isolation. Building robust resilience relies on multi-domain integration. Much of the tech on display during UDT will therefore showcase the integration of land, maritime, air, space, and cyber domains. This will be further explored later in the year at DSEI, where there will be a focus on greater interoperability and integration across all domains, an effort that will involve both traditional and non-traditional companies.

Thus, while our navies are undoubtedly operating in an increasingly contested maritime domain, the collaboration we are witnessing across Europe, NATO, and allies, serves as a crucial asset. Events over the past couple of months in particular have reinforced and publicised the importance of securing our maritime borders, both for national, international, and economic security. Therefore, as government delegations, industry leaders, and defence experts gather in Oslo for UDT, improving undersea defence capabilities and establishing a cohesive and decisive strategy to deter threats will be at the forefront of conversation.

This article is sponsored by Clarion Events.