The damage to the Estlink 2 power cable, which became public knowledge on 25 December, has drawn attention to the vulnerability of critical infrastructure in the Baltic Sea. The recent incident, in which the cargo ship Eagle S caused serious disruptions not only to the Estlink 2 energy link but also to four other cables connecting Finland to Estonia and Germany, clearly demonstrates the vulnerability of our region's critical infrastructure. While investigations are ongoing, the incident highlights the complex interplay between law, regional security and geopolitical tensions.
The damage to the Estlink 2 cable calls into question the protection of submarine cables and pipelines, which are critical to the security of energy supply and balancing prices in Estonia and Finland. According to initial reports, the Cook Islands-flagged tanker Eagle S dragged its anchor along the seabed for tens of kilometres, damaging several cables in the process. Although no formal findings have been made, the incident has raised significant questions about negligence, intent and the adequacy of existing safety measures.
Legal analysis
Although the exact location where the Eagle S was detained by the Finnish authorities has not been disclosed, it is believed to be within the Exclusive Economic Zone (EEZ). Following the detention, the tanker was escorted into Finnish waters near the port of Porvoo Kilpilahti. During the investigation, an attempt by the owners of the Eagle S to have the detention lifted was rejected, meaning that the vessel will remain in detention pending the outcome of the investigation.
The legal implications of the Estlink 2 incident are grounded in international maritime law. Under Article 58 of the United Nations Convention on the Law of the Sea (UNCLOS), which Russia, the EU, and the Cook Islands are parties to, states enjoy freedom of navigation in EEZ, but must “have due regard to the rights and duties of the coastal State and shall comply with the laws and regulations adopted by the coastal State in accordance with the provisions of this Convention and other rules of international law.” This means they have a duty to protect submarine cables and pipelines. Moreover, Article 79 of UNCLOS affirms the right of states to lay and maintain submarine cables there, while imposing an obligation on other states to avoid actions that may damage these structures. More specifically, Article 113 considers any injury to such pipelines and cables as a “punishable offence” whether it occurs “wilfully” or “through culpable negligence.” If it is proven that Eagle S acted intentionally or somehow negligently, Estonia and Finland could invoke these provisions to hold its owners accountable.
In addition, the 1884 Convention on Submarine Cables, although now dated, reinforces the obligations of states to protect and ensure the uninterrupted operation of such infrastructure. It can also be used to support legal proceedings.
Regional and practical implications
Although the Eagle S sailed under the Cook Islands flag, the evidence strongly suggests that it is part of a Russian "Shadow Fleet". Lloyd's List has claimed that the Eagle S was “was loaded with spying equipment,” which, if proven, would indicate a deliberate Russian attempt to sabotage and spread tensions within the EU's energy infrastructure. Without prejudging the ongoing investigation, Russia should be clearly warned against this course of action. Given the current political climate between the EU and Russia, which makes direct negotiations impractical, indirect channels should be used to send a clear message to Moscow: further escalation of the targeting of energy infrastructure is a mutually destructive path. Reinforced by strong security guarantees and a coordinated regional response, this message could deter future incidents. The cost of such escalation - whether in terms of economic stability or public confidence - is simply too high.
As a practical step in the right direction, Estonia proposed expanding NATO's presence in the Baltic Sea, including a surveillance mission to prevent future incidents. While Finland responded quickly and effectively to the Eagle S incident, it may also be necessary to improve surveillance systems, such as real-time sensors on critical cables, which can provide early warnings and shorten response times.
It is also important to develop regional cooperation. Estonia and Finland need to share information and increase their efforts to protect infrastructure. Consideration should also be given to improving legislation to enable more effective prosecution of sabotage and negligence outside national territorial waters.
Conclusion
Incidents such as the Estlink breach are a wake-up call for greater cooperation in the Baltic Sea region. The legal framework is strong, but political will and regional cooperation are needed to enforce it. It is important to understand that legal and military measures alone will not solve the problem. A pragmatic approach that balances assertiveness and strategic deterrence is urgently needed to prevent such incidents. Improved maritime surveillance, legal accountability and indirect diplomatic engagement are all necessary components of a comprehensive response. By addressing this issue collectively and strategically, Estonia, Finland and their allies can protect their infrastructure while sending a strong message against the weaponisation of energy networks.