Inclusive and equitable cooperation in BBNJ implementation: A comparative analysis of institutional design

The Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction (BBNJ Agreement) is finalised, but the regime is entering a formative implementation phase. As the process moves from the Preparatory Commission to the first Conference of the Parties, Parties must interpret treaty provisions, adopt rules of procedure, and put institutional arrangements into operation. This paper examines how post-negotiation institutional design choices shape equitable cooperation in BBNJ implementation, understood as the conditions that make access, participation, and influence possible when State capacity is unequal. It focuses on small island developing States (SIDS), which face structural constraints in multilateral ocean governance. We derive SIDS-centred equity criteria from the treaty text, SIDS circumstances, and expressed priorities. We then evaluate three comparator regimes, the United Nations Framework Convention on Climate Change (UNFCCC), the Convention on Biological Diversity (CBD), and the International Seabed Authority (ISA), across four design domains: UN relationship and institutional structure, secretariat leadership, institutional finance and participation support, and review and accountability. We find that the UNFCCC model most consistently embeds participation support and recurring review cycles into standing procedures, while the CBD offers strong UN anchoring but relies more heavily on externally administered finance and information-based review without routine follow-up. The ISA concentrates authority in upstream bodies and technical processes and has faced chronic constraints in participation support. We conclude by translating these lessons into near-term institutional choices for COP I.