Undersea Cables and the Weaponisation of Connectivity
By Rakotoarimanga Tinah | 13 November 2025
Summary
Recent incidents in the Baltic and Red Seas underscore that undersea cables, carrying 97–99% of global data, have become strategic assets and targets.
State and proxy actors increasingly use cable interference as a grey-zone tool of cyber and maritime coercion.
It is highly likely that governments and private operators will strengthen seabed surveillance and redundancy measures to counter this growing threat.
Background
Undersea fibre-optic cables form the physical backbone of the global internet, transmitting almost all intercontinental data traffic, including financial exchanges, cloud services, and military communications. Despite their strategic importance, these networks remain privately owned and lightly protected, often beyond national jurisdictions.
Since 2023, a series of disruptions has drawn attention to their vulnerability
In October 2023, damage to the Balticconnector pipeline and nearby cables between Finland and Estonia prompted NATO to enhance maritime monitoring.
In February 2024, several cables in the Red Sea were severed amid the Yemen conflict, temporarily disrupting up to 25 % of traffic between Europe and Asia.
In August 2025, Finland charged the crew of the Russia-linked NewNew Polar Bear tanker for alleged sabotage of Baltic cables, though the case was later dropped for lack of proof showing persistent attribution challenges.
Meanwhile, the South China Sea and Taiwan’s Matsu Islands have experienced repeated cuts, which Taipei attributes to Chinese fishing vessels, revealing how such incidents can serve both strategic messaging and intelligence purposes.
Governments have begun to respond. The European Union launched its Action Plan on Submarine Cable Security while NATO’s “Baltic Sentry” initiative expands undersea domain awareness. The United Kingdom commissioned the RFA Proteus under the MROSS programme to monitor and protect seabed infrastructure. However, with more than 500 active cables spanning oceans, comprehensive protection remains difficult.
Implications
Cable sabotage gives states leverage by sending a message, disrupting, and intimidating without declaring open conflict. The lack of clear international rules regarding who is responsible for protecting these cables, especially under the UN Convention on the Law of the Sea, makes this space vulnerable to exploitation. For Russia and China, keeping things vague works to their advantage; it allows them to act, deny and still gain influence in contested waters.
When a single cable goes down, the effect goes far beyond one coastline. Everything connected to data flow, such as banking, logistics, and even military coordination. For example, the Red Sea incident in 2024 demonstrated how a single break can ripple across continents, delaying transactions and shutting down parts of the cloud for hours. Repairs take time, ships are few, and the weather also rarely cooperates.
Both Russia’s GUGI and China’s PLAN have developed fleets capable of mapping, tapping, or physically cutting cables. What was once the realm of espionage has become a military capability. They can gather intelligence, test responses, or quietly disable communications if conflict escalates. The arrival of autonomous underwater vehicles makes it harder to trace or deter. It’s a silent contest for control of the seabed, and the line between surveillance and sabotage is disappearing fast.
Nathaniel Sison/Unsplash
Forecast
Short-term (Now - 3 months)
It is likely that NATO and EU members will increase real-time seabed monitoring and data-sharing in the Baltic and North Seas.
Medium-term (3-12 months)
It is highly likely that governments will establish public-private partnerships with telecom operators to improve mapping and emergency response capacity.
Long-term (>1 year)
It is likely that rival powers will develop autonomous underwater vehicles for both surveillance and sabotage, while international law remains unable to attribute attacks clearly.
