18 further countries have deposited their ratifications at the event in Nice, France, with just 11 more needed to reach "critical threshold" for the treaty's entry into force.
The EU, together with 6 individual EU member states, formally ratified the treaty in New York this week, bringing the total number of ratifications to 28.
International agreement was reached on 5 March 2023 to safeguard biodiversity and sustainability for the high seas, protecting 30% of the world's oceans.
Norway is the 31st country to ratify the international ocean agreement, Biodiversity Beyond National Jurisdication (BBNJ) at the United Nations in New York on 4 June.