Are Fragile Subsea Cables a Hidden Risk to EU Commerce?

Europe’s subsea cables act as the silent foundation of the continent’s digital and energy systems. These critical cables carry more than 95% of all global internet traffic and support an estimated US$10tn in daily financial transactions, according to the International Institute for Strategic Studies.

They are also essential to energy exchange between countries, acting as connectors in the continent’s evolving power networks.

The geopolitical environment surrounding this infrastructure grows more strained. Surveillance, suspected sabotage and questions about whether current repair capabilities can cope with a serious failure put the spotlight on how vulnerable these subsea assets have become.

Dr Sidharth Kaushal from the Royal United Services Institute says attention from state-backed actors is increasing: “We have seen an uptick in activity of Russian surveillance."

Recent anchor-dragging incidents damaging cables in the Baltic Sea are under investigation. While some incidents involve vessels of interest, the idea of a coordinated Russian “shadow fleet” remains unconfirmed.

In the UK, Defence Secretary John Healey MP shares similar concerns. He says the Russian vessel Yantar is “used for gathering intelligence and mapping the UK’s critical underwater infrastructure”.

The attention paid to underwater assets is mirrored in Westminster. Matt Western MP, Chair of the UK’s National Security Strategy Committee, describes the subsea cable network as “an increasingly vulnerable soft underbelly”, while also noting “a good degree of resilience and awareness of the challenges growing”.

To address these concerns, the European Union launches its EU Action Plan on Cable Security in February 2025, committing around US$1.1bn to modernise infrastructure and reinforce surveillance systems across the continent.

The strategy focuses on four areas: prevention, detection, response and repair, alongside deterrence measures.

Cable protection: A supply chain issue?

Subsea cables are deeply tied to trade and supply chains. These “invisible arteries” support the free flow of commerce, energy and services.

Any disruption can ripple across sectors. This is why the industry voices concern not just about security, but about the ability to restore damaged links fast enough to avoid economic fallout.

The EU’s Henna Virkkunen, Executive Vice-President for Tech Sovereignty at 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 puts the Network and Information Security Directive (NIS2) and the Critical Entities Resilience (CER) Directive into focus. These aim to harmonise how Member States handle risk, coordinate responses and monitor vulnerabilities.

On the ground, prevention measures involve maritime safety rules and the use of commercial sensors, drones and autonomous underwater vehicles. Detection systems get a boost with vessel-tracking tools and basin-wide surveillance, enabling early warnings. A “Cable Security Toolbox” of mitigation methods is expected once coordinated risk mapping concludes in Q4 2025.

The supply chain implications do not stop at monitoring. If a cable is damaged, a quick repair depends on access to the right ships, skilled crews and the ability to cross regulatory borders without delay. Industry groups including the European Subsea Cables Association and the International Marine Contractors Association call out these gaps.

They warn of “an ageing global fleet of cable-laying and maintenance vessels”, labour shortages and regulation delays. These, they say, are slowing recovery times and threaten continuity of both digital services and power supplies. Their joint statement pushes for a streamlined permitting process, more investment certainty and an expansion of Europe’s repair-vessel fleet.

Increasing global resilience 

At the legal level, cutting or damaging subsea cables carries serious consequences.

In the UK, this is covered by the Submarine Telegraph Act 1885. Across the EU, individual Member States handle enforcement under international law, guided by frameworks like NIS2 and CER which set standards for security but do not introduce shared criminal statutes.

Deterrence is part of the strategy. This includes accountability for those responsible and stronger international coordination through NATO and joint diplomatic statements like the “New York Joint Statement on the Security and Resilience of Undersea Cables”.

A key concern is the security of components. Some cables contain technology from high-risk vendors. This opens another vulnerability, leading to calls for trusted supply chains that exclude unsecure equipment.

For the European Commission, urgency is central. Delays in applying protective measures only increase exposure to attack or disruption. The Commission states that no single country can solve the problem alone. Effective protection of these cables requires a joint approach involving governments, telecoms providers and international allies.

The allocation of US$1.1bn and the development of unified regulatory responses are part of a wider effort to protect Europe’s infrastructure. The aim is to support economic resilience and guarantee energy and data continuity as the region faces a more contested environment.

Safeguarding these assets demands more than surveillance – it calls for durable collaboration, regulation that matches the scale of the threat and readiness to respond. For Europe’s economy and supply chains to function uninterrupted, subsea cables must remain secure and swiftly repairable.