Governing Critical Subsea Infrastructure in the Baltic Sea: Complementing UNCLOS Through the EU Resilience Framework

Sammanfattning

This thesis examines the extent to which the European Union’s resilience framework, particularly the Critical Entities Resilience Directive (CER) and the Directive on Measures for a High Common Level of Cybersecurity across the Union (NIS2), complements the legal framework established under the United Nations Convention on the Law of the Sea (UNCLOS) regarding the governance and protection of critical subsea infrastructure in the Baltic Sea. The thesis focuses specifically on submarine cables and pipelines and addresses the structural limitations of existing legal frame-works in relation to contemporary threats. The thesis applies a legal dogmatic method and analyses relevant sources of public international law and EU law through treaty interpretation and EU legal methodology. UNCLOS is interpreted in accordance with the Vi-enna Convention on the Law of Treaties (VCLT), while the analysis of EU law proceeds in light of the teleological and systematic interpretative methods commonly applied within EU law. The thesis demonstrates that UNCLOS establishes the foundational legal framework governing submarine cables and pipelines through its allocation of rights and jurisdiction between States in different maritime zones. While coastal States possess comparatively broad enforcement powers within the territorial sea, the Convention relies more heavily on flag State jurisdiction, due regard obligations and inter-State cooperation beyond territorial wa-ters. The thesis argues that this structure creates practical and legal chal-lenges regarding the protection of subsea infrastructure against contempo-rary threats in the Baltic Sea, particularly where incidents involve foreign-flagged vessels, multiple jurisdictions or suspected hybrid threats. In contrast to UNCLOS, the CER and NIS2 Directives establish a broader resilience-oriented framework focused more directly on the protection, continuity and risk management of critical infrastructure and essential ser-vices. Through obligations relating to risk assessments, cybersecurity, su-pervision and cross-border cooperation, the Directives seek to reduce vul-nerabilities and strengthen the management of disruptions affecting subsea infrastructure. The thesis argues that the EU resilience framework complements the UN-CLOS regime by addressing several challenges that UNCLOS was not orig-inally designed to manage. At the same time, the thesis emphasises that the EU framework continues to operate within the broader jurisdictional struc-ture established under UNCLOS and therefore cannot fully eliminate the Convention’s structural limitations. Nevertheless, the relationship between UNCLOS and the EU resilience framework is particularly significant in the Baltic Sea context due to the high degree of regional integration between the surrounding coastal States and the transnational nature of subsea infra-structure in the region.