Securing Europe’s Subsea Cables: Network Resilience Urged

Europe’s subsea cable infrastructure supports nearly all intercontinental data flow and a significant portion of the continent’s energy network.

These “invisible arteries” carry more than 95% of global internet traffic and are essential to financial markets, energy exchange and societal functions.

The International Institute for Strategic Studies highlights the magnitude of the infrastructure, noting that cables “transmit around 95% of global data flows and underpin an estimated $10tn in financial transactions every day”.

Against this backdrop, the risk environment for subsea cables has intensified considerably due to geopolitical tensions, sabotage attempts and ageing repair capabilities.

Experts like Dr Sidharth Kaushal from the Royal United Services Institute (RUSI) observe escalating surveillance activity from state-backed actors.

“We have seen an uptick in activity of Russian surveillance,” Sidharth explains. This has included surface vessels and uncrewed submersibles near critical cables, reflecting strategic efforts by nation states to map and potentially disrupt undersea infrastructure.

"Russia’s 'shadow fleet' often drags anchors in the Baltic Sea, causing multiple cable cuts and compounding the activity with real-time disruption across northern Europe," he adds.

Elsewhere, the UK's Defence Secretary, John Healey, has confirmed concerns about Russian monitoring vessels near Britain’s undersea assets, describing the vessel Yantar as “used for gathering intelligence and mapping the UK's critical underwater infrastructure".

The events led the UK’s National Security Strategy Committee chair, Matt Western MP, to describe the national cable network as "an increasingly vulnerable soft underbelly."

Nevertheless, Matt acknowledges that "we have a good degree of resilience and awareness of the challenges growing".

In response, the European Union introduced the EU Action Plan on Cable Security in February 2025, channelling nearly US$1.1bn into key upgrades for digital infrastructure and surveillance systems.

The plan highlights a four-pillared approach: prevention, detection, response and repair and deterrence. 

Henna Virkkunen, Executive Vice-President of Tech Sovereignty for the European Commission, says: “Agreeing on the infrastructure mapping and coordinated risk assessment is the first key building block in implementing our EU Action Plan on Cable Security.”

The plan focuses on the rapid implementation of directives like NIS2 and Critical Entities Resilience (CER), ensuring unified risk assessments and surveillance protocols across Member States.

Prevention efforts focus heavily on eliminating vulnerabilities by establishing designated offshore zones, restricting fishing and anchoring and enforcing real-time monitoring through commercial sensors and unmanned air and underwater vehicles.

Meanwhile, detection capabilities are enhanced by integrated sea basin surveillance and vessel tracking systems, enabling early warnings.

The European Commission anticipates completing coordinated risk mapping by Q4 2025, supporting a forthcoming 'Cable Security Toolbox' of mitigation measures.

Industry bodies such as the European Subsea Cables Association (ESCA) and International Marine Contractors Association (IMCA) have welcomed the efforts but issue warnings about current repair capacities.

They highlight risks posed by an ageing global fleet of cable-laying and maintenance vessels exacerbated by regulatory obstacles across borders.

ESCA and IMCA’s joint statement flags that “regulatory barriers, a shortage of skilled offshore workers and the lack of readily available solutions” could delay restoration efforts critical for digital and energy continuity.

They argue that Europe needs to streamline permitting regimes, increase investment certainty and expand the repair vessel fleet urgently.

From a legal perspective, damaging subsea cables is a prosecutable offence under UK and EU statutes. The laws derive from historical frameworks such as the Submarine Telegraph Act of 1885 and extend to modern international maritime law.

Authorities highlight deterrence by holding responsible parties accountable and call for stronger international collaboration through forums such as NATO and the UN’s 'New York Joint Statement on the Security and Resilience of Undersea Cables'.

Efforts at the international level include developing trusted supply chains to eliminate unsecure components, a vulnerability noted in cables incorporating equipment from high-risk vendors. 

The European Commission remains cautious but clear about the need for prompt rollout of risk mitigation tools, as delays invite undue exposure.

As noted in commentary on evolving policy, while the EU still shapes comprehensive regulations, "reducing untrusted equipment in subsea cables minimises exposure to potential backdoor vulnerabilities" remains a critical step for safeguarding government, military and corporate data flows.

Looking forward, the European Commission has confirmed that no single Member State can address these challenges alone.

Instead, a cooperative model involving government agencies, telecommunications operators and international allies must form the backbone of Europe’s subsea cable security strategy. 

The investment of almost US$1.1bn and ongoing regulatory refinement illustrate commitment to securing the continent’s critical infrastructure, safeguarding economic stability and maintaining uninterrupted connectivity in an increasingly contested geopolitical environment.

In sum, safeguarding European subsea cables means a comprehensive approach combining stringent regulation, innovative technology deployment, international partnerships and industry collaboration.

The integrated effort aims not only to prevent physical and cyber threats but to guarantee a resilient and rapidly reparable network essential to the digital economy and energy transition.

As IT and telecommunications leaders prepare for heightened risks, the alignment of policy, technology and operational readiness remains vital to fortify Europe’s undersea cable network against evolving threats.