In September 2025, the international community crossed a decisive threshold in ocean governance. The so-called High Seas Treaty secured its 60th ratification, triggering its entry into force on 17 January 2026. This moment marks the culmination of two decades of negotiation and signals a long-awaited step towards legal protection of the world’s “oceanic commons”. The High Seas Treaty marks an extension of international environmental law since the 1982 UN Convention on the Law of the Sea.

Among other International ownership treaties, the Antarctic Treaty System, Outer Space Treaty, and Moon Treaty, the High Seas Treaty addresses the vast marine territories, International waters, that lie beyond any national jurisdiction — the so-called high seas. These waters begin roughly 200 nautical miles from coastlines, where Exclusive Economic Zones end, and they make up nearly half of the planet’s surface. Until now, they have remained largely ungoverned, subject to fragmented sectoral management by fisheries organisations or maritime law, and vulnerable to overexploitation, deep-sea mining, and bioprospecting. The High Seas Treaty establishes a legally binding global framework to conserve and sustainably use biodiversity in these areas.

Once the high seas treaty enters into force on 17 January 2026, it will provide a global framework to help achieve international biodiversity targets, including the pledge to protect 30 per cent of land and sea areas by 2030 under the Kunming-Montreal Global Biodiversity Framework.

The new agreement allows for the designation of Marine Protected Areas on the high seas, giving the international community the legal tools to safeguard ecologically critical regions. It requires environmental impact assessments for activities that may affect marine ecosystems, introduces equitable benefit-sharing mechanisms for marine genetic resources, and provides for technology transfer and capacity building, ensuring that developing states can participate meaningfully in ocean stewardship.

For example, for companies engaged in deep-sea mining, this means a new order of accountability. While the Treaty does not outlaw seabed exploitation, it obliges states and operators to conduct environmental impact assessments under international scrutiny. Licences will depend not only on technical capacity but on compliance with biodiversity safeguards and equitable benefit-sharing provisions. In practice, the Treaty inserts ecological due process into what was until now a frontier economy.