The European subsea cable network is a vital piece of Critical Infrastructure for EU member states. This network is essential to European society, and any disruption or damage could have far-reaching consequences across the region. Given the rapidly shifting threat landscape and rising geopolitical tensions, especially following recent instances of apparently deliberate damage to undersea cables in the Baltic Sea, operators of critical infrastructure face mounting challenges.
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To adequately support the digital economy and the ongoing green energy transition, as well as the development of the innovative technologies that drive both, operators must counter intentional threats while also managing risks from accidents, natural hazards, and climate change. These risks, in addition to being threats, can also amplify the effects of deliberate kinetic and cyber-attacks. Ensuring the resilience of subsea cables requires specialized technological innovations that go beyond the current state of the art. Ensuring that Europe leads in the development and deployment of next-generation resilient and sustainable subsea cable technologies, there is an urgent need for a EU-wide Strategic Roadmap for Submarine Cable Resilience.
Introduction
Europe’s digital economy and societal well-being rest on a foundation that is often invisible: submarine cables. Throughout this article, the term “submarine cables” primarily refers to undersea data-transmission systems, the networks that carry most of the world’s internet traffic. However, many of the resilience principles discussed also apply to submarine energy interconnectors and, more broadly, to Europe’s critical undersea infrastructures such as power cables and pipelines. This undersea infrastructure carries most of the global internet traffic, ensuring the continuity of services that range from online banking and international trade to healthcare, emergency communications, and energy connectivity. Their reliable operation is often taken for granted, yet their vulnerability has never been more apparent. As history shows, submarine cables have long been exposed to disruption. The 1884 Convention for the Protection of Submarine Telegraph Cables already identified the risks of accidental damage from activities such as fishing and anchoring (Convention for the Protection of Submarine Telegraph Cables, 1884). While those risks persist today, the stakes have multiplied. In the 21st century, even short interruptions can trigger cascading consequences across Europe’s digital society, economy, and security. Recent incidents of apparently deliberate cable damage underscore that these infrastructures are not just technical assets but also potential targets in an era of rising geopolitical tension (European Commission, 2023).
These challenges are magnified by several converging trends. First, the rapid expansion of the data economy creates soaring demands on bandwidth and reliability. Entire sectors, from finance to logistics, depend on uninterrupted data flows. Second, the green transition places new demands on submarine energy cables that connect offshore wind farms and interconnect national grids. As the European Green Deal highlights, such infrastructure must be rolled out “further and faster to support the EU’s climate and energy objectives” (European Commission, 2019). Third, climate change and natural hazards introduce new risks to marine infrastructures, from undersea landslides to increasingly extreme weather events.
Alongside environmental and economic pressures, the threat landscape itself is shifting. Deliberate attacks, whether involving physical sabotage or cyber intrusion, can exploit the very interconnectedness that makes submarine cables so essential. When combined with accidental damage or natural hazards, such attacks can amplify vulnerabilities and leave societies exposed. As emphasised by Hummelholm (2024), the cybersecurity dimension of these risks deserves particular attention. Many vulnerabilities arise not only in the deep-sea segments but at the shore-end systems and in network management software. Strengthening resilience therefore requires segmented architectures, active anomaly detection, and cross-border information-sharing frameworks that align with EU-level cyber policy initiatives.
The Joint Communication on Strengthening the Security and Resilience of Submarine Cables identifies Prevention, Detection, Response, Repair, and Deterrence as the five essential pillars of resilience (European Commission, 2023). Similarly, the United Nations Institute for Disarmament Research (UNIDIR) stresses the importance of absorptive, restorative, and adaptive capabilities in the face of hybrid risks (UNIDIR, 2022). The stakes are not only technical but also strategic. Submarine cables underpin Europe’s digital sovereignty, ensuring that citizens, governments, and businesses can trust the continuity and security of their communications. They are equally crucial for strategic autonomy, enabling the EU to reduce dependency on external suppliers in critical domains such as repeaters, smart sensors, and repair technologies. Without secure and resilient cables, Europe’s vision of a robust digital single market and a decarbonised energy system is placed at risk.
Against this backdrop, the absence of a dedicated, forward-looking Roadmap becomes evident. Current efforts remain fragmented, scattered across telecom, energy, and maritime domains. Coordination between authorities, operators, and industry is often weak, and governance mechanisms lag behind the pace of technological change. What is needed is a EU-wide Strategic Roadmap for Submarine Cable Resilience: a unifying Roadmap that brings together technology foresight, investment planning, risk preparedness, sustainability, and governance into one coherent European framework. Such a roadmap would not only secure Europe’s immediate resilience but also chart a path for the next two decades, ensuring that technological innovation, environmental responsibility, and strategic autonomy advance hand in hand.
Why a Roadmap is Needed
Safeguarding Europe’s Digital Backbone
The everyday reality of Europeans, accessing healthcare records, paying bills and navigating public transport, relies on a hidden infrastructure that is rarely noticed until it fails. Submarine cables are the digital backbone of European society, and disruptions carry not only financial costs but also deep societal consequences. Multi-day outages can cost between €50 and €100 million per day, while also undermining trust in essential services. A roadmap would help prioritise technologies and governance mechanisms that reduce outage risks, improve response capacity, and ensure continuity of services (European Commission, 2023).
Strategic Autonomy and Digital Sovereignty
Europe’s dependency on external suppliers in sovereignty-sensitive domains poses significant risks. Repeaters, advanced optical amplifiers, and specialised repair vessels are often sourced outside Europe, leaving critical gaps in autonomy. A European roadmap would identify priority domains where Europe must invest to secure its independence, echoing the ambitions of the NIS2 Directive (Directive (EU) 2022/2555) and the CER Directive (Directive (EU) 2022/2557), both of which emphasise the need for resilience planning across critical infrastructures. In this context, the implications of Brexit also influence Europe’s digital sovereignty landscape. While data transfers to the United Kingdom currently benefit from an EU adequacy decision, long-term resilience planning should consider developing direct intra-EU submarine data routes that bypass non-EU territory. Such routes would strengthen compliance with data-protection requirements and enhance Europe’s capacity to maintain secure and jurisdictionally clear connectivity within the Single Market (European Commission, 2021).
Sustainability and the Green Transition
Resilience is inseparable from sustainability. Repair and replacement operations are costly, time-consuming, and environmentally disruptive. Embedding circular economy principles into submarine cable planning (such as recycling decommissioned cables, sourcing low-impact materials, and designing for reuse) reduces ecological footprints and strengthens supply security. Such measures directly support the European Green Deal and Europe’s offshore renewable energy ambitions, where submarine energy cables form the arteries of a decarbonised grid. The future also lies in multi-purpose smart cables, capable of combining data connectivity with environmental monitoring, delivering value not only to operators but also to marine science and climate resilience (UNIDIR, 2022).
Overcoming Fragmented Governance
Today’s governance mechanisms are patchy, divided between national authorities, sector-specific agencies, and industry-led associations. Cross-border coordination remains weak, despite the inherently international nature of submarine networks. A roadmap would provide a structured governance framework, ensuring that technological innovations are embedded within operational and policy frameworks, and that cooperation across borders becomes the norm rather than the exception.
How the Roadmap Can Be Built
Developing an EU level Roadmap for submarine cable resilience requires more than technical expertise, it demands a structured, transparent, and inclusive process that bridges science, policy, and operations. Such a process should combine analytical depth with broad stakeholder participation to ensure that the resulting strategy is both evidence-based and operationally relevant.
At its core, the roadmap should be foresight-driven, aligning research and innovation priorities with real-world needs and long-term policy objectives. The approach involves systematically identifying emerging technologies, risks, and trends; validating these findings with experts and stakeholders; and translating them into concrete research, investment, and policy actions. By linking technological foresight with governance and investment planning, Europe can ensure that strategic decisions are informed by both current realities and future challenges.
A multi-track approach offers particular value. Instead of treating technology, investment, and policy as separate silos, these dimensions should evolve in parallel and continuously inform each other. Technological development must be considered alongside governance mechanisms, regulatory needs, and funding models. Integrating these tracks ensures that innovations can be deployed effectively within coherent legal and operational frameworks, and that investments are guided by shared resilience priorities.
Stakeholder engagement must be embedded throughout the process. Operators, technology providers, national authorities, EU agencies, and researchers all have distinct perspectives on risks and dependencies. Their engagement—through surveys, workshops, and cross-sector dialogues—ensures inclusivity, legitimacy, and practical relevance. Sensitive discussions should be handled under appropriate confidentiality frameworks, balancing openness with security needs.
Ultimately, the roadmap should deliver actionable outputs: a clear set of research and innovation priorities, investment recommendations, and policy pathways that strengthen Europe’s capacity to prevent, detect, respond to, and deter disruptions to its undersea infrastructure. By adopting such a structured and participatory approach, Europe can ensure that its roadmap becomes not just a strategic document, but a living instrument for resilience, sustainability, and technological leadership.
A Phased Vision for Europe’s Future
To remain relevant and actionable, the roadmap must look across three horizons.
In the short term (2026–2030), Europe must address immediate vulnerabilities by improving resilience metrics, piloting advanced sensing and monitoring solutions, and initiating governance dialogues that strengthen trust and cross-border cooperation. The medium term (2031–2035) should focus on scaling validated technologies, such as next-generation fibre optics, predictive maintenance supported by robotics, and advanced cybersecurity frameworks, while embedding resilience standards into policy and regulation. In the long term (2036–2045), Europe can aim for intelligent, self-healing cable systems, highly automated repair capabilities, and multi-purpose cables integrating environmental monitoring. By then, governance frameworks should mature into a truly integrated system where resilience, sustainability, and strategic autonomy converge.
Conclusion
Submarine cables are the lifelines of Europe’s digital economy and the arteries of its green transition. Yet they are increasingly exposed to threats ranging from geopolitical sabotage to environmental hazards, compounded by fragmented governance and weak cross-border coordination. Europe urgently needs a Strategic Roadmap for Submarine Cable Resilience, a Roadmap that aligns technology foresight, investment planning, sustainability, and governance. Such a Roadmap would secure Europe’s digital sovereignty and strategic autonomy, safeguard citizens and businesses from costly disruptions, advance the goals of the European Green Deal, and establish Europe as a global leader in sustainable, resilient submarine cable innovation.
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