The third United Nations Ocean Conference (UNOC3) will take place in Nice from 9 to 13 June 2025, co-hosted by France and Costa Rica. Following previous editions in New York in 2017 and Lisbon in 2022, the upcoming summit is positioned as a cornerstone event for global ocean governance and sustainability efforts, coming a decade after the Paris Agreement on climate.
Bringing together UN member states, international agencies, civil society, the private sector, and global donors, the conference is set to address mounting environmental pressures on the world’s oceans. Covering over 70% of the Earth’s surface, oceans are crucial for regulating climate, sustaining biodiversity, supporting economic exchange, and connecting communities. However, they face serious threats from climate change, pollution, and overexploitation.
UNOC3 aims to accelerate implementation of Sustainable Development Goal 14, which focuses on the conservation and sustainable use of oceanic and marine resources. The conference’s ambition is anchored in three core objectives: advancing multilateral ocean-related negotiations, mobilising financing for sustainable ocean use and the blue economy, and promoting ocean science to guide political decision-making.
A key outcome will be the Nice Action Plan for the Ocean, expected to include a political declaration and a roster of voluntary commitments from stakeholders. The five-day programme will feature morning plenary sessions for state-level commitments and afternoon “Ocean Action Panels” designed to foster partnerships and projects among governments, UN bodies, NGOs, scientists, and private actors.
The event will run alongside several major side forums. From 3 to 6 June, the One Ocean Science Congress, organised with France’s Ifremer and CNRS, will convene 2,000 scientists to discuss ocean health and sustainable use. On 7 June, the Ocean Rise and Coastal Resilience Summit will gather leaders from coastal cities and island nations to share knowledge and enhance climate resilience. Monaco will host the Blue Economy and Finance Forum on 7–8 June, targeting investment in sustainable maritime industries.
Nice will also celebrate World Ocean Day on 8 June with parades, performances and public gatherings, culminating in a large-scale celebration on the Bay of Angels. From 28 May through the conference, a public-facing “Green Zone” on the Nice port and at the rebranded Palais des Expositions will host exhibitions, debates and cultural programming to raise awareness of ocean issues.
In a broader effort to spotlight marine conservation, the city of Nice will dedicate much of 2025 to ocean-themed events. The Carnival of Nice will focus entirely on the ocean, while the Biennale of Oceanic Arts will stage over 50 exhibitions across museums and public spaces from May to October. Throughout the conference, more than 500 side events involving participants from nearly 150 countries are expected to showcase actionable solutions to safeguard marine environments worldwide.
