Submarine cables, which carry over 95% of international data, are facing heightened threats from accidental damage and deliberate sabotage amid rising geopolitical tensions. Governments and industry experts call for stronger collaboration, enhanced legal frameworks, and technological innovation to safeguard this critical infrastructure.
Submarine fiber-optic cables underpin nearly all international internet traffic, supporting everything from everyday communications to vital financial and governmental operations. Spanning about 1.5 million kilometres under the sea, these cables handle vast volumes of data with the latest capable of transmitting data at rates allowing the equivalent of the entire digitised Library of Congress to be transferred multiple times every second.
Rising Incidents and Threat Landscape
According to Insikt Group’s recent assessment and data from SubTel Forum, reported submarine cable faults hit record highs in 2024 and 2025, with physical damage from fishing and anchoring remaining the predominant cause. Despite this, recent incidents in hotspots like the Baltic Sea and Taiwan Strait indicate an increased risk of low-level state-sponsored sabotage. Vessels linked to Russia and China have been associated with suspicious anchor dragging causing multiple cable faults, although definitive blame remains complex due to the covert nature of these acts.
Vulnerabilities at Cable Landing Stations
A major concern highlighted by cybersecurity firms and agencies is the clustering of multiple cables at single landing stations. This concentration increases the risk that sabotage or espionage at a single landing site could disrupt connectivity across multiple cables with far-reaching global impact. Such landing stations are critical hubs where undersea cables connect to terrestrial networks, making them attractive targets for power disruptions or cyberattacks.
Government Measures and Regulatory Responses
Governments worldwide are stepping up to protect submarine cables, recognising them as critical infrastructure. The US Federal Communications Commission (FCC) recently implemented rules barring foreign adversary-controlled entities, including Chinese and Russian firms, from owning or controlling subsea cable projects. These rules enforce cybersecurity and physical security standards aimed at shielding cables from hostile interference.
Necessity of Public-Private Collaboration
Industry actors heavily invest in resilience measures such as route diversification and rapid repair capabilities. However, the private sector faces significant challenges, including complex permitting processes, national security restrictions, and high costs, which hinder cable deployment and maintenance. The latest policy recommendations stress streamlined approval processes and enhanced coordination among government agencies and private cable owners to accelerate infrastructure expansion and safeguard existing networks.
Technological Advances for Cable Security
Emerging technologies like fiber sensing promise real-time detection of physical threats to cables, enabling faster incident response. Enhanced use of tracking systems such as Automatic Identification System (AIS) and Vessel Monitoring Systems (VMS) are advocated to monitor maritime activity near cables and reduce accidental damage. In terms of data security, the shift toward quantum-resistant encryption algorithms is underway to prevent interception or tampering with the vast data flows.
Challenges of Supply Chain Security
The global supply chain for submarine cable technology is concentrated, raising concerns about reliance on certain vendors viewed as untrustworthy. Governments encourage diversification and risk assessment of suppliers to reduce vulnerabilities to espionage or sabotage hidden in equipment or software, particularly from high-risk authoritarian states.
An Escalating Theatre of Cyber-Physical Hybrid Threats
Experts warn that the distinction between physical sabotage and cyber warfare targeting undersea cables is blurring. State-sponsored cyberattacks involving malware insertion in cable landing stations or attacks against related energy grids reveal a new dimension of threats. Advanced persistent threat (APT) groups from Russia, China, Iran, and North Korea are active in this arena, employing increasingly sophisticated tactics.
International Cooperation Imperative
Given the transnational nature of submarine cable infrastructures, enduring protection depends on multinational cooperation. Security alliances like NATO and the Quad could facilitate intelligence sharing, joint patrols, and aligned regulatory frameworks. However, new plurilateral agreements may be necessary to credibly deter state-backed cable sabotage and cyber operations.
Protecting submarine cables is paramount to securing the foundation of the global digital economy and critical infrastructure. As geopolitical tensions grow, combined physical and cyber threats require coordinated efforts by governments, industry, and international partners. Streamlined regulations, advanced technologies, diversified supply chains, and strengthened legal frameworks form the cornerstones of robust submarine cable security now and into the future.
Brussels Morning is a daily online newspaper based in Belgium. BM publishes unique and independent coverage on international and European affairs. With a Europe-wide perspective, BM covers policies and politics of the EU, significant Member State developments, and looks at the international agenda with a European perspective.
