A landmark UN treaty protecting nearly half the planet’s ocean has officially entered into force, marking a new era for marine conservation.

The High Seas Treaty, formally known as the Agreement on Marine Biological Diversity of Areas Beyond National Jurisdiction (BBNJ), became international law on Friday after two decades of negotiations.

The treaty establishes the first-ever legal framework to protect biodiversity in international waters beyond any country’s control, covering regions that make up nearly 50% of Earth’s surface.

What does the treaty do?

The agreement provides tools to create marine protected areas on the high seas and sets clear obligations for sustainable use of ocean resources.

It also includes provisions for capacity building, technology sharing, and mechanisms to ensure benefits from marine resources are distributed fairly among nations.

The treaty is expected to play a crucial role in achieving the global target of protecting 30% of the world’s oceans by 2030.

Two decades in the making

Negotiations for the treaty began more than 20 years ago, with the final text agreed in March 2023.

The treaty required ratification by 60 countries to come into effect, a milestone reached in September 2025. Following a 120-day waiting period, it has now become international law.

So far, 83 countries have joined the agreement, with more encouraged to sign up ahead of the first Conference of Parties (CoP), scheduled within the next year.

What happens next?

Several legal obligations take effect immediately, including requirements for environmental impact assessments for any planned activities that could affect the high seas.

Governments must also publicly notify such activities and promote the treaty’s objectives in other international bodies governing shipping, fisheries and seabed mining.

A UN Preparatory Commission is currently developing the treaty’s institutional framework and decision-making processes, with proposals to be adopted at the first CoP.

Countries are also being encouraged to identify important high seas sites requiring protection ahead of future meetings.

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Photo credit: Artan Sadiku, Unsplash