Implementing the BBNJ Agreement: From flag States to the home States of individuals and corporations conducting activities at sea

The 2023 Agreement on Biodiversity Beyond National Jurisdiction (BBNJ Agreement), which entered into force on 17 January 2026, frames its core obligations in terms of activities and natural or juridical persons ‘under [States’] jurisdiction or control.’ This communication argues that this formulation engages a wider category of States than the flag State alone: primarily the home State of individuals and corporations directing activities at sea—typically the State of their nationality or domicile. It situates the Agreement’s obligation framework within the no-harm principle and identifies existing precedents—in international fisheries law and in the deep seabed mining regime—in which the law of the sea already recognizes home State responsibility beyond the flag State. Against the backdrop of widespread use of open ship registries and complex corporate structures across different jurisdictions, early implementing legislation illustrates the risk that a flag-centered approach may leave regulatory gaps and the occasional difficulties in determining, in concrete cases, which State is that with ‘jurisdiction or control’ over BBNJ-relevant activities and persons—that is, which is the home State. This communication suggests that the BBNJ Conference of the Parties should specifically address these issues for the Agreement’s effective implementation.