The United Kingdom has formally ratified the High Seas Treaty, completing the final step in a process that will allow the country to play a full role in implementing one of the most significant ocean protection agreements in history.

Foreign Secretary Yvette Cooper signed the instrument of ratification, with officials confirming the document will be formally deposited with the United Nations in New York today. The move comes more than two years after the UK first signed the Biodiversity Beyond National Jurisdiction Agreement – known as the BBNJ Agreement or High Seas Treaty – in June 2023, following more than a decade of negotiations at the UN in which the UK played a leading role.

The treaty aims to safeguard ecosystems across international waters, which cover nearly two thirds of the world’s ocean. It establishes, for the first time, a legal mechanism to create marine protected areas on the high seas, enabling the conservation of vulnerable habitats and species – including sharks, whales and sea turtles – in waters that have until now existed largely beyond the reach of enforceable protection. 

It also sets rules for the fair sharing of benefits derived from marine genetic resources, with significant potential applications in medicine, biotechnology, agriculture and scientific research.

Foreign Office minister Seema Malhotra said the ratification marked a turning point for international ocean governance. 

“The ocean is one of our planet’s greatest shared resources, supporting livelihoods, food security and biodiversity. By ratifying the BBNJ Agreement, the UK is turning international ambition into action and helping to protect vulnerable marine habitats and species. A healthy ocean is essential for food security and climate resilience in the UK and around the world. Today’s milestone demonstrates our commitment to protecting it for future generations,” she said.

Environment minister Emma Hardy, who announced at last year’s UN Ocean Conference that the UK would bring forward the legislation necessary for ratification, said the commitment had now been honoured. “I’ve always believed the ocean is one of our planet’s greatest treasures, supporting nature, communities and our climate. When I announced at the UN ocean conference last year that the UK would bring forward legislation to enable ratification of the BBNJ Agreement, I was determined that this commitment would lead to meaningful change. 

“I’m proud that the UK has now ratified this landmark agreement.”

The treaty entered into force in January, having passed the required threshold of 60 countries. As of today, more than 90 nations have formally adopted the agreement, including China, France, Japan and Brazil. Environmental groups welcomed the ratification but had previously criticised ministers for moving at a “glacial pace” in the months since the treaty became internationally binding.

With ratification now complete, attention turns to implementation – and in particular to how ambitiously countries move to establish meaningful marine protected areas across international waters. 

Dr Judith Brown, Projects Director at Blue Marine Foundation, said the ratification reflected a broader pattern of UK leadership on ocean protection, but that the harder work now lay ahead. 

“The UK’s ratification of the High Seas Treaty, joining more than 90 countries that have now formally adopted the agreement, is a major step forward for ocean protection. It mirrors the leadership the UK has already shown through the Blue Belt Programme, which has helped safeguard vast areas of ocean across its Overseas Territories,” said Brown. 

“With the treaty now entering implementation, attention must turn to delivering ambitious, highly protected marine protected areas on the high seas. The treaty provides a once-in-a-generation opportunity to protect biodiversity across the two-thirds of the ocean beyond national borders, and we hope the UK will continue to lead by championing the strong protections needed to make that vision a reality.”

The BBNJ Agreement also reinforces the UN Convention on the Law of the Sea as the foundation of international ocean governance and supports delivery of the UN Global Biodiversity Framework, which includes the 30by30 target.

Click here for more from the Oceanographic Newsroom.