International legal norms defining the law of the sea only answer the question of whether these spaces are under the sovereignty of any state or not.

International law of the sea has become conventional (the 1958 UN Convention on the Law of the Sea, the 1982 comprehensive UN Convention on the Law of the Sea, which establishes the legal status and regime of all maritime spaces and the living and mineral resources of the World Ocean and its seabed).

The 1982 United Nations Convention on the Law of the Sea (entered into force on November 16, 1994) was the first in the history of international relations that set for all nations, without exception, the territorial sea limit – 12 nautical miles, and also defined the basic criteria of the continental shelf limits and the outer limits of the waters of the archipelagos.

Inner maritime waters. Legal status of inland maritime waters is determined by the state that has a sea coast, as they are part of the state’s territory.

Inland maritime waters include:

(1) The waters between the shore of the state and the straight baselines from which the width of the territorial sea is counted.

Where the coastline is deeply indented and winding, or where there is a chain of islands along the coast and in its immediate vicinity, the method of straight baselines connecting the respective points may be applied to draw the baseline from which the width of the territorial sea is measured;

2) seaport waters (up to the line passing through the most prominent permanent port facilities in the sea, which are considered as part of the coast),

3) waters of bays whose shores belong to the same state (up to a line where the width of the natural entrance to the bay reaches 24 nautical miles),

4) waters of “historic bays” regardless of the width of the entrance to them. All foreign vessels are required to abide steadfastly by the laws and regulations of the coastal state while in port. Foreign vessels and their crews are subject to the civil, administrative jurisdiction of the coastal state, which, however, usually refrains from exercising such jurisdiction in matters pertaining to the domestic law and order of the foreign vessel.

Civil jurisdiction includes the competence of the judicial institutions of the coastal State to hear suits arising from the failure of the foreign vessel and its owners to perform contracts or contractual obligations, and the right of port authorities to detain or arrest a foreign vessel in order to secure suits or judicial decisions.

The competent authorities of a coastal State shall refrain from exercising criminal jurisdiction over seafarers of foreign merchant ships when the offence they commit on board their ship does not affect the interests of the coastal State, the rights and freedoms of its citizens or violate its public order.

Military foreign ships may enter open seaports only after receiving prior permission or invitation from the coastal State. If they do not comply with the laws and regulations of the coastal state, the coastal state has the right to demand that the foreign warship leave the limits of internal maritime waters.

Territorial sea (“territorial waters”) is a sea band, adjoining the coast or inland sea waters of a state up to 12 nautical miles wide and by its legal status is a part of the territory of a coastal state (or archipelago state). The outer boundary of the territorial sea is the state maritime boundary of the state.

Although the legal regime of the territorial sea is determined by the coastal state, all coastal states are obliged, under international law, to ensure compliance with the universally recognized right of innocent passage through their territorial sea. This is the essential difference between the legal regime of territorial waters and the legal regime of internal sea waters.

A passage is considered peaceful if it does not violate the peace, good order and security of the coastal state. All warships also have the right of innocent passage, and are immune from the criminal and civil jurisdiction of the coastal state. Submarines must follow the surface and fly their flag.

Immunity from jurisdiction is also recognized for government vessels operated for non-commercial purposes. Beyond the outer boundary of the territorial sea lie the international maritime spaces – the high seas.

+The open sea is the maritime space outside the territorial sea of states. It is not subject to the sovereignty of any state. The legal regime and legal status of the high seas is determined by the international law of the sea.

The freedom of the high seas includes, in particular, the freedom of navigation and flight, the freedom to lay submarine cables, pipelines and construct artificial islands and installations.

All ships on the high seas are subject to the exclusive jurisdiction of the state whose flag they fly.

The contiguous zone is the area of the high seas adjacent to the outer limit of the territorial sea. The contiguous zone is established by a coastal state, when necessary, to control compliance by foreign ships with customs, fiscal, immigration and sanitary rules in its internal sea waters and territorial sea.

The sovereignty of the coastal State shall not extend to the contiguous zone. The width of the contiguous zone shall not exceed 24 nautical miles, which shall be measured from the baselines used to measure the width of the territorial sea.

Exclusive economic zone (economic zone) an area of the high seas outside and adjacent to the territorial sea. According to Article 57 of the UN Convention on the Law of the Sea (1982) the width of exclusive economic zone shall not exceed 200 nautical miles, counted from baselines from which the width of the territorial sea is measured.

The peculiarity of the legal regime of the economic zone is that the coastal state has sovereign rights for exploration, development and conservation of natural resources (living and non-living) in its waters, on the seabed and in its subsoil, as well as for management of all these resources of the zone.

The 1982 UN Convention on the Law of the Sea provides for the jurisdiction of the coastal state within the economic zone with respect to the establishment and use of artificial installations and structures, marine scientific research, protection and preservation of the marine environment.

All other states enjoy in the economic zone the freedoms of navigation and flight, laying, cables and pipelines and other uses of the sea within the high seas that are related to these freedoms.

The continental shelf is geographically an underwater extension of the continent (mainland). The Convention of 1982 defined the continental shelf of a coastal State as “the seabed and subsoil of the submarine areas extending beyond its territorial sea throughout the natural prolongation of its land territory to the outer edge of the continental margin or to a distance of 200 nautical miles from the baselines from which the breadth of the territorial sea is measured, where the outer edge of the continental margin does not extend at this distance” (Article 76, par. 1).

Where the outer limit of the continental shelf extends beyond 200 nautical miles, it shall be permitted to extend beyond 350 nautical miles from the baselines from which the breadth of the territorial sea is measured (article 76, par. 5).

Under the 1982 Convention coastal states exercise sovereign rights over the continental shelf for the purpose of exploration and exploitation of its natural resources. These rights are exclusive: if the coastal State does not develop the natural resources of its shelf, “no one may do so without the express consent of the coastal State” (Art. 77).

The sovereign rights of coastal states on the continental shelf do not affect the legal status of the high seas covering it and of the airspace above those waters. Therefore the exercise of these rights shall not prejudice the exercise of navigation, air travel and other rights and freedoms provided for in the 1982 Convention for the high seas.

International Seabed Area. To ensure a harmonized legal order for the activities of all states for exploration and development of mineral resources of the seabed beyond the continental shelf, it was decided at the 3rd UN Conference on the Law of the Sea to declare this seabed area and its resources as the “common heritage of mankind” and to call it the Area for short.

The 1982 UN Convention established the principles defining the legal status and regime of the area. These are basically the following: (1) no State shall claim or exercise sovereignty or sovereign rights over any part of the Area and its resources; (2) no State, person or entity shall take possession of any part of the Area or its resources; (3) the Area shall be open to all States, whether coastal or landlocked, for peaceful purposes only, without discrimination.

Straits used for international navigation (international straits). Straits geographically connect two seas to an ocean, or parts of the same sea, ocean. Many of them serve as the only possible sea route for international navigation, so they became known as international straits, the UN Convention 1982 provides that in straits used for international navigation “between one part of the high seas or exclusive economic zone and another part of the high seas or exclusive economic zone”, all ships and aircraft enjoy the right of transit passage, “which shall not be hindered”.

Archipelagic waters are waters within an archipelagic State, these waters are delimited from other parts of the sea around the archipelagic State by straight archipelagic lines (baselines) which connect “the outermost points of the archipelagic islands and fringing reefs” (Article 47 of the 1982 Convention). As a rule, the length of such baselines should not exceed 100 nautical miles (to prevent unjustified expansion of the water area of archipelagic waters).

Baselines thus drawn around the archipelago, form the boundary of archipelagic waters. It is from this boundary that the archipelagic state measures the width of its territorial sea, contiguous zone, exclusive economic zone and continental shelf.

Archipelagic waters are subject to the sovereignty of the archipelagic State: sovereignty also extends to the airspace over archipelagic waters, to their bottom and subsoil and to their resources. This is the great similarity between archipelagic waters and inland maritime waters. But there is one significant difference, which has led to the designation of archipelagic waters as a special type of maritime space. According to the Convention of 1982, without prejudice to the legal regime of internal sea waters, which can exist within archipelagic waters (water of ports, bays), ships of all the states enjoy the right of innocent passage through archipelagic waters. Such passage is characteristic of the legal regime of the territorial sea.