From Mare Liberum to Mare Clausum: The Transformation of the Ocean Regime and the Role of the Navy

The article examines the transformation of the legal regime of the World Ocean, in which the formula “everything not prohibited is permitted” is giving way to the formula “permitted is what has been agreed with the authority managing the sea area”. The erosion of the zonal compromise of the 1982 UN Convention on the Law of the Sea is shown to proceed from two directions: the institutionalisation of high seas governance under the BBNJ Agreement, which entered into force in 2026, and the unilateral expansion of coastal jurisdiction on environmental and security grounds. Counter-measures against the shadow fleet as a basis for interference with navigation (the Marinera and Eagle S cases), new forms of the use of force at sea and the Red Sea experience are considered separately. Three functions of navies — protection of navigational rights, law enforcement and convoy escort — and the risks of their collision are analysed. The author proposes ways of adapting the law of the sea without revising the Convention: interpretation of the relationship between area-based management tools and freedom of navigation, a proportionality test for environmental restrictions, clarification of the status of ships whose nationality is contested, a regime for unmanned systems and subsea infrastructure, an incident-prevention mechanism between navies, and amendments to Russian legislation.