The Third United Nations Ocean Conference (UNOC3) is took place from 9 to 13 June 2025 in Nice, France, co-hosted by France and Costa Rica, with the theme “Accelerating action and mobilizing all actors to conserve and sustainably use the ocean” . Its primary aim is to drive urgent implementation of Sustainable Development Goal 14—protecting and sustainably using marine resources—by translating political will into concrete action such as ratifying the High Seas (BBNJ) Treaty, expanding marine protected areas, reducing plastic pollution, promoting sustainable fisheries, and decarbonizing shipping. Through a series of events—including the One Ocean Science Congress, a coastal resilience summit, and a blue economy finance forum—UNOC3 brings together governments, scientists, civil society, Indigenous Peoples, the private sector, and financiers to forge evidence-based, multi-stakeholder partnerships and the "Nice Ocean Action Plan".