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Maritime security

Undersea cables and North Sea security: the invisible infrastructure at risk

By Vantage Subsea Editorial Published 2026-06-10 9 min read
Image: Vantage Subsea image library / Radar imagery

Key takeaway: Undersea cables carry 95% of intercontinental data. The North Sea is a critical junction. OEUK has called for critical infrastructure designation. The Royal Navy is increasing monitoring operations.

Over 95% of intercontinental data traffic travels through undersea cables. The North Sea is a critical junction for cables connecting the UK to Europe and beyond. Growing geopolitical tensions have put this infrastructure in the spotlight.

Why undersea cables matter

Subsea cables are the backbone of the global internet, carrying over 95% of intercontinental data traffic. The North Sea is a critical junction, with cables connecting the UK to Norway, Denmark, the Netherlands, Germany and beyond.

These cables are not just for internet traffic. Offshore wind farms use subsea cables to transmit power to shore. Oil and gas platforms rely on subsea control systems. Financial institutions depend on low-latency cable connections for trading.

Windward's latest Undersea Cables Risk Report highlights significant concentrations of vessel activity around critical subsea routes, raising concerns about accidental damage and deliberate interference.

The threat landscape

In April 2026, the Royal Navy completed ten days of focused operations monitoring Russian warships and a submarine in UK waters as part of coordinated NATO efforts. The operation highlights the ongoing maritime security dimension of North Sea activity.

On 10 June 2026, OEUK called for increased focus on emerging threats to UK offshore oil, gas and offshore wind farms, urging that offshore installations be designated as critical national infrastructure.

The threat is not only military. Trawling, anchoring, seismic surveys and construction activity all pose risks to subsea infrastructure. Climate change-driven seabed movement and increased storm activity add further stress.

What protection looks like

Critical infrastructure designation would bring enhanced protection measures, including restricted zones around key assets, increased monitoring and coordinated response protocols.

The National Cyber Security Centre provides guidance relevant to businesses of all sizes, including marine suppliers who connect into larger operators through email, portals and subcontracting chains.

For the marine sector, awareness of cable routes, careful anchoring practices and reporting of suspicious activity are practical steps that contribute to collective security.

Read the maritime security sector page for governance and resilience context.

Maritime security sectorResources

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