Ocean Science Meets Diplomacy: Contribution of the One Ocean Science Congress to the Third United Nations Ocean Conference

Abstract This paper reviews the outcomes of the One Ocean Science Congress (OOSC) and its strategic alignment with the Third United Nations Ocean Conference (UNOC3) as a case study in ocean science diplomacy. Convened in June 2025 in Nice, France, as a UN Special Event immediately preceding UNOC3, the OOSC introduced an innovative model for multilateral conferences by providing a direct channel for transmitting science‐based recommendations to policymakers. This sequencing sought to ensure that political deliberations were anchored in the most current knowledge. The extent to which OOSC outputs influenced UNOC3 discussions and outcomes is analyzed. While causality cannot be firmly established, evidence shows that 44 of the 60 OOSC recommendations are reflected in UNOC3 documents, indicating substantial uptake. Notable alignments include recognition of the importance of international cooperation in ocean research and the inclusion of indigenous knowledge systems in governance frameworks. Voluntary commitments, such as a precautionary pause on deep‐sea mining, further mirrored OOSC's core messages. The paper concludes that the OOSC–UNOC3 sequence demonstrates the potential of strategically timed, policy‐ready scientific inputs to enhance the science–policy interface. Interest from future UNOC hosts in replicating this approach underscores its promise as a model for embedding science into high‐level ocean governance.