The Prosecution ‘Gap’ for Attacks on Subsea Cables and Pipelines

Recent incidents in the Baltic Sea and elsewhere have exposed both the vulnerability of undersea infrastructure and the fragility of the legal order meant to protect it. While recent pieces on EJIL: Talk! and in Ocean Development & International Law address key facets, this post takes a step back to map the wider prosecutorial gap and the systemic jurisdictional uncertainties it reveals.

The explosions that damaged the Nord Stream gas pipelines between Russia and Germany in 2022, the rupture of the Balticconnector gas pipeline between Finland and Estonia in 2023, and the repeated cutting of data cables in the North and Baltic Seas in 2022–2025 demonstrate how easily commercial ships can be weaponised to sever the arteries of the modern economy. Yet, in the aftermath of each event, the same question resurfaces: who has the right to investigate, arrest, and prosecute? The answer remains far from clear.

A Legal Regime Built for Ships, Not Cables

The law of the sea was mainly drafted with vessels and resources in mind. The 1982 United Nations Convention on the Law of the Sea (UNCLOS) and the 1884 Convention for the Protection of Submarine Telegraph Cables (Paris Convention) offer limited rules on undersea infrastructure. While coastal States enjoy sovereign rights over the exploration and exploitation of resources in their exclusive economic zone (EEZs) and continental shelf, the general freedom to lay and maintain cables and pipelines is preserved for all States (UNCLOS Arts 58(1) and 79(1)). In addition, coastal States have some regulatory competence, particularly where pipelines connect to their territory or continental shelf (UNCLOS Art 79(4)), but that competence is narrowly defined.

Article 113 of UNCLOS requires flag States to criminalise the breaking or injury of submarine cables and pipelines outside the territorial sea. The same duty in relation to telegraph cables appears in earlier form, in the Paris Convention (Art II). Yet enforcement hinges entirely on the flag State, which may have no interest in pursuing the matter. In addition, few States have enacted the necessary implementing legislation, leaving a gap between the formal obligation and prosecutorial capacity. The imbalance is striking: while UNCLOS expressly empowers coastal States to exercise jurisdiction over artificial islands, structure, installations, and navigational safety zones (Arts 60 and 80), it leaves the protection of cross-border submarine cables and pipelines largely to the flag State of a vessel that damaged such critical infrastructure. 

Eagle S and the gap of jurisdiction

The Finnish prosecution of the Eagle S demonstrates this gap vividly. On Christmas Day 2024, the tanker’s anchor dragged for nearly a hundred kilometres across the seabed, severing several submarine cables and a power interconnector linking Finland and Estonia before it was interdicted by the Finish authorities. The ship caused serious economic damage particularly in Estonia, but also in Finland. Yet in October 2025, the Helsinki District Court dismissed the charges, ruling that Finland lacked jurisdiction. 

The court treated the episode as an “incident of navigation” under Article 97 of UNCLOS, which limits penal proceedings to the flag State or the nationality of the accused. Because the Eagle S flew the Cook Islands flag and was crewed by foreign nationals, Finnish courts concluded they could not proceed. 

This reasoning is revealing. The court viewed the incident through the lens of navigation and the high seas freedoms, rather than through the lens of Finland’s sovereign rights in its EEZ, its duty to protect the marine environment, or even the possibility that deliberate attacks on undersea infrastructure could, in certain circumstances, fall within the definition of piracy under Article 101(a)(ii) of UNCLOS. Whether Article 97 was ever intended to cover anchor damage to subsea infrastructure rather than collisions is debatable, but the case illustrates how easily adjudicative jurisdiction slips away when courts default to flag-State primacy. The decision has been appealed (see further here).

The Swedish Prosecution Authority has already announced that it closed its investigation into another Baltic Sea cable cut attributed to the anchor-dragging by the Maltese-flagged bulker Vezhen. The prosecutor concluded that the cable break was accidental, caused by a combination of severe weather and technical failure, and that there was no legal basis to pursue a negligence offence.

Balticconnector and Emerging State Practice

The rupture of the Balticconnector in October 2023 – again caused by anchor dragging, this time severing both a gas pipeline and communication cables – prompted Finland and Estonia to test the limits of their jurisdictional powers.

They set up a joint criminal investigation, with Finland emphasising that the incident occurred within its EEZ, while Estonia described the damage as an attack on critical infrastructure. Both positions reflected a view that coastal State jurisdiction can extend to acts in the EEZ that threaten essential national interests.

The States later identified the Newnew Polar Bear, a Hong Kong-flagged container ship, as the probable source of the damage after recovering its anchor near the rupture site. Requests for cooperation were sent to China, but despite Estonian and Finnish diplomatic efforts they neither confirmed an investigation nor accepted responsibility, exposing the weakness of the flag State model under Article 113 of UNCLOS. Yet much depends on ongoing proceedings. Earlier this year, the ship’s Chinese captain was taken into custody and charged before a Hong Kong court with criminal damage to property without lawful excuse. If the case results in conviction, it could demonstrate that the flag State model, though fragile, can still deliver accountability. The case has been adjourned to December for further investigation. The case of the Yi Peng 3, however, offers little cause for optimism.

In November 2024, the Yi Peng 3, another Chinese-owned cargo vessel, was suspected of damaging two cables connecting Sweden to Lithuania and Finland to Germany. Both were located in the Swedish EEZ. China opened an investigation into the ship but declined Sweden’s request for its prosecutor to board the vessel, despite earlier assurances of cooperation. According to Sweden’s foreign minister, Chinese authorities permitted Swedish police and accident investigators to attend only as observers within a Chinese-led inspection. The vessel subsequently departed the region, and no prosecution followed.

In response to the two incidents, Finland announced it was considering options to strengthen enforcement measures against cable cuts beyond the territorial sea. Poland amended its Protection of Shipping and Seaports Act and Estonia amended its EEZ Act and the Defence Forces Organisation Act, explicitly authorising enforcement measures against acts endangering subsea infrastructure within the EEZ. Estonia has further proposed amendments to its Penal Code to extend criminal jurisdiction over foreign ships and nationals operating in its EEZ, invoking the protective and effects principles of legislative jurisdiction.

Together, these initiatives signal a significant evolution in State practice: a possible willingness to reinterpret, inter alia, UNCLOS Articles 56, 79, and 221 in favour of broader coastal State competence. 

Nord Stream and the Boundaries of Adjudicative Jurisdiction

Poland’s recent refusal to extradite a suspect sought by Germany in connection with the Nord Stream explosions again shows how fragile adjudicative jurisdiction becomes once an incident occurs beyond the territorial sea. The 2022 blasts destroyed sections of three gas pipelines running from Russia to Germany across the Baltic Sea, in the EEZs of Denmark and Sweden. Both Denmark and Sweden launched investigations but ultimately closed them, citing a lack of jurisdiction over conduct that occurred outside their territorial sea and involved foreign vessels and nationals. Their withdrawal left Germany to pursue the matter alone under domestic law.

In late September 2025, Germany issued arrest warrants for at least six people, including a Ukrainian diver, who was apprehended in Poland in late September. A Polish court not only found that Germany lacked jurisdiction but also characterised the destruction of the pipelines as a legitimate wartime act by Ukraine against the infrastructure of an aggressor State. Judge Dariusz Łubowski described such actions as “diversionary acts” that could not constitute crimes “under any circumstances”. Professor Kai Ambos called the decision “non-legal” and “politically driven” noting that civilian pipelines cannot be reclassified as a military objective by political assertion. Yet this matter is not so clear-cut. Even though the pipelines likely served as civilian objects at the time of the explosions, it could be argued under a doctrine long-held by the United States that the Nord Stream pipelines broadly contributed to Russia’s war-sustaining effort, thereby potentially making the pipelines a legitimate military objective (see further here).

The Polish Prime Minister, Donald Tusk, reinforced the political tone by declaring that “[t]he problem with Nord Stream 2 is not that it was blown up. The problem is that it was built”. Germany’s muted reaction suggests that neither side wished to escalate a politically fraught issue in which the law offered little clarity. The episode illustrates how, in such cases, international law provides no clear allocation of adjudicative jurisdiction.

The Polish court’s decision follows a ruling by the Italian Supreme Court on 15 October 2025, which annulled an earlier judgment authorising the extradition to Germany of another Nord Stream suspect. Both cases transformed what is ordinarily a routine procedure – the transfer of a suspect between EU member states under the European Arrest Warrant – into a highly political affair.

Stateless Ships and Expanding Enforcement

A related challenge arises when ships involved in suspicious activity lack nationality. In 2025, Estonia and France boarded and inspected the Kiwala (later renamed Boracay), a tanker believed to belong to the Russian ‘shadow fleet’. Both States treated the ship as stateless under Article 110(1)(d) of UNCLOS, which authorises warships to visit vessels without nationality on the high seas or in the EEZ. Reportedly, since 2025, a significant number of tankers carrying Russian oil have an unclear flag registration. In practice, this provision allows in certain cases States to interdict and inspect ships suspected of endangering subsea infrastructure. 

Estonia later attempted to interdict another suspected shadow-fleet tanker, the Jaguar, but the operation failed when a Russian fighter jet intervened. These episodes show that, even where interdiction is possible, enforcement remains constrained by political realities and limited enforcement jurisdiction beyond the territorial sea.

A vessel’s statelessness itself can, in some legal systems, give rise to detention or prosecution. Because stateless ships enjoy no protection from any flag State, they may be visited, boarded, and searched by any State. However, statelessness does not itself create universal criminal jurisdiction over acts committed on board; any prosecution must still rest on a recognised jurisdictional basis under domestic law. In practice, most coastal States limit their response to inspection and expulsion, and few have translated this residual universality into sustained criminal proceedings.

Reassessing the Legal Foundations

Taken together, these cases highlight the difficulty of applying existing law to the realities of hybrid warfare. UNCLOS offers only a limited framework for attributing criminal jurisdiction over the intentional or reckless damage of subsea cables and pipelines. Articles designed to protect navigation do not readily address deliberate interference with critical infrastructure. The result is a persistent uncertainty in which accountability often depends on the willingness of the flag State.

One notable response has come from Estonia, which is amending its Penal Code to rest on the protective principle and the effects doctrine. While the limits of the effects doctrine remain contested, several States employ to capture conduct with substantial domestic impact. Legislation of this kind, if adopted more widely, could help bridge the jurisdictional gap.

Other suggestions include clarifying that acts causing severe economic or infrastructural harm to coastal States fall within the notion of offences against “fundamental interests,” thereby permitting use of the protective principle. Some scholars go further, arguing that deliberate attacks on undersea cables could qualify as piracy, thereby granting all States universal enforcement powers. This is a bold but textually defensible interpretation that would at least avoid the current paralysis. That said, it would apply only to attacks committed for “private ends,” excluding acts directly attributable to States.

Conclusion

The above cases show how difficult it remains to bring the perpetrators of subsea sabotage to justice. Each incident highlights a different fragment of the legal mosaic: the limits of adjudicative jurisdiction, the weakness of enforcement powers, the uncertainty of prescriptive reach, and the challenges posed by flagless ships. The cumulative effect is to leave critical undersea infrastructure largely unprotected by criminal law beyond the territorial sea. Unless States adapt their domestic laws and cooperative mechanisms to reflect the realities of an interconnected seabed and hybrid warfare, the law risks ending in jurisdictional paralysis.