Clandestine submarine armadas targeting European underwater infrastructures face off in shallow seas

In recent years, the Baltic Sea has become a focal point of concern for European authorities, as numerous incidents of underwater cable destruction have been linked to Russian activities as part of hybrid warfare. This hybrid warfare includes the use of civilian ships from Russia's shadow fleet, which have been implicated in sabotage under various flags.

These destructive activities have significant implications, as more than 60% of Russia's seaborne crude oil exports transit through the Baltic Sea. This makes the region a vital artery for global energy supplies, and any disruptions could have far-reaching consequences.

In an effort to strengthen its maritime presence and surveillance in the Baltic Sea, NATO launched Baltic Sentry in January 2025. This mission aims to bolster security and deter potential threats.

The European Union has also taken steps to protect its undersea cables. In February 2025, the EU introduced its own Cable Security Action Plan, which aims to safeguard these vital connections. Additionally, European authorities have seized several Russian vessels suspected of damaging critical infrastructure.

However, the challenge extends beyond mere enforcement. Europe must prioritize mapping its existing and planned undersea infrastructures to prevent connectivity and security disruptions. This includes not only energy pipelines but also the vast network of data cables that transmit approximately $10,000 billion in daily financial transactions and 97% of global internet traffic.

The Baltic Sea's strategic importance lies in its geographical position, as it serves as a bridge between Russia and key members of NATO and the EU. In light of this, Europe must avoid over-reliance on a single gas pipeline or data cable and mandate companies to develop backup systems.

Moreover, Europe should increase costs for hostile actors by stricter enforcement of sanctions that close current loopholes and prevent Moscow from maintaining significant revenues. This could include measures such as the temporary suspension of certain maritime laws by Baltic Sea states to impose stricter controls on Russian oil shipments.

The recent unveiling of a new subsea device by China capable of cutting undersea cables up to a depth of 4,000 meters serves as a reminder of the evolving nature of these threats. European leaders and intelligence agencies are being urged to be more assertive in deterring threats to critical infrastructures, as German Defense Minister Boris Pistorius has done.

In conclusion, failing to act decisively today exposes Europe to far greater threats tomorrow. Europe must remain vigilant, strengthen its deterrence posture, and hold those responsible for sabotage accountable through effective attribution, such as forensic analysis. By doing so, Europe can protect its vital interests and maintain its security in the face of hybrid threats.

Clandestine submarine armadas targeting European underwater infrastructures face off in shallow seas