Who Governs the High Seas?

The High Seas Treaty entered into force on 17 January 2026, after Morocco became the sixtieth country to ratify it on 19 September 2025. It is the first instrument that allows marine protected areas to be established in international waters, which is a larger gap than most people realise had existed.

How the ocean is divided

The 1982 UN Convention on the Law of the Sea set the framework, and everything else hangs off it.

A coastal state holds sovereignty over its territorial sea out to 12 nautical miles. Out to 200 miles it holds an exclusive economic zone, with rights over resources but not full sovereignty, so foreign vessels navigate freely while fishing and extraction are controlled. Beyond that lies the high seas, where the water column belongs to nobody and everybody.

The seabed beneath the high seas is treated separately. UNCLOS calls it the Area and designates it common heritage of mankind, administered by the International Seabed Authority.

Note what that split does. The water column and the seabed underneath it fall under different legal regimes, managed by different bodies, with different rules.

What BBNJ was for

UNCLOS established freedom of the high seas without establishing much machinery to protect them. Fisheries were handled by regional management organisations with patchy coverage and weaker enforcement. There was no mechanism at all to designate a protected area beyond national jurisdiction.

Roughly two-thirds of the ocean sat outside any framework capable of protecting a specific place.

The BBNJ agreement addresses four things: area-based management including marine protected areas, environmental impact assessment for activities on the high seas, marine genetic resources and how benefits from them get shared, and capacity building with technology transfer toward developing states.

Marine genetic resources were the hardest to negotiate. Organisms from deep-sea vents and other extreme environments have commercial value in pharmaceuticals and industrial enzymes, and the question of who benefits when a company patents something derived from a sample taken in international waters had no answer for decades.

The seabed argument runs separately

The ISA has been developing regulations for mineral extraction in the Area. During its thirtieth session in July 2025 the Council completed the remaining regulations, 56 through 107, of the mining code, resuming a second reading of the revised consolidated text.

As of December 2025 roughly forty states support a moratorium on mining the Area, citing environmental risk and unresolved questions about benefit sharing.

The ISA sits in an uncomfortable position by design. UNCLOS gives it both the job of organising activities in the Area and the job of protecting the marine environment from them, and those mandates pull against each other whenever a contractor applies.

Enforcement is the unresolved part

A treaty entering into force is a legal event, not an operational one.

Flag state jurisdiction governs vessels on the high seas, which means enforcement depends on the state where a ship is registered, which is frequently a state with limited capacity or limited interest. Open registries make this worse. A protected area in the middle of an ocean has no coastguard.

Satellite monitoring has changed the detection picture substantially. AIS tracking, and radar and optical imagery for vessels that have switched their transponders off, make it far harder to fish unobserved than it was ten years ago. Detection is not the same as prosecution, and the gap between the two is where most high seas enforcement fails.

What happens next

Implementation detail gets worked out at the first Conference of the Parties, expected within a year of entry into force. That meeting decides how protected areas actually get proposed, assessed and designated, which is where the treaty either acquires teeth or does not.

Sixty ratifications brought it into force. There are close to two hundred states, and the ones whose participation matters most for high seas fishing are not uniformly among the sixty.