Introduction to the International Law of the Sea
International Law of the Sea is the system of international rules governing the extent of a coastal State sovereignty on the sea, the rights and obligations of a coastal States and other subjects of an International Law of the Sea, their mutual relations regarding the exploration and exploitation of living and non-living resources of the sea and seabed, their duties concerning the protection of the marine environment from pollution and many other rights and obligations. This article will not be focused on the historical development of the International Law of the Sea, nor its sources. In order to explain the extent of the sovereignty and jurisdiction over the sea, maritime zones will be discussed. Maritime zones are invisible borders at sea, which are defined by the 1982 United Nations Convention on the Law of the Sea (hereinafter: the Convention), determining the sovereignty and jurisdiction of the coastal States and the rights of third countries (coastal or landlocked) in these zones. The maritime zones are Territorial sea, Contiguous zone, Exclusive Economic Zone, Continental shelf, High Seas and The Area.
The territorial sea is a maritime zone where the coastal State enjoys absolute sovereignty, as in the area of the territorial sea, and the air space over the territorial sea as well as to its seabed and subsoil. The sovereignty of the coastal State is reflected in the fact that it has sole rights on the exploitation of all living and non-living natural resources, sited not only in the water, but also on its seabed and subsoil. The Article 3 of the Convention states that every State has the right to establish the breadth of its territorial sea up to the limit not exceeding 12 nautical miles, measured from the baselines determined in accordance with this Convention.
According to the Article 33 of the Convention, each coastal State can determine its contiguous zone, which may not extend beyond 24 nautical miles from the baselines from which the breadth of the territorial sea is measured. The contiguous zone overlaps with the Exclusive Economic Zone and the Continental shelf. It should be emphasized that the contiguous zone coastal State does not have ipso facto, therefore it has to be declared. The Convention recognizes certain jurisdiction over this maritime zone to the coastal State. Thus, the coastal State has the right to prevent infringement of its customs, fiscal, immigration or sanitary laws and regulations within its territory or territorial sea; and to punish infringement of the above laws and regulations committed within its territory or territorial sea.
Exclusive Economic Zone
The Exclusive Economic Zone is an area beyond and adjacent to the territorial sea and it shall not extend beyond 200 nautical miles, measured from the baselines from which the breadth of the territorial sea is measured. Just as the contiguous zone, the State must declare the length of its Exclusive Economic Zone, but even if it does not do it, however, a State is entitled to its sea bed (the continental shelf). The Convention states that a coastal State has sovereign rights for the purpose of exploring and exploiting, conserving and managing the living and non-living natural resources, but also the other rights enumerated in Article 56 of the Convention. In this zone, third States have certain rights such as freedom of navigation and overflight, laying pipelines or cables on the seabed and all other rights enumerated in Article 58 of the Convention.
The continental shelf includes only the seabed and the subsoil, and determination of its border represent important economic issue, since a costal State has a sovereign right on exploitation of natural resources that lie on it. It has to be emphasized that the continental shelf does not cover the water surface which is located above it, therefore sometimes it can happen that the jurisdiction over the continental shelf has one State, and water surface above it is determined as the High Seas. According to the Article 76 of the Convention, continental shelf of a coastal State comprises the seabed and subsoil of the submarine area that extend 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 up to that distance. From this definition it can be concluded that the length of the continental shelf can be measured in two ways, firstly taking into account the natural structure of its continental margin, or secondly by applying the strict rule of 200 nautical miles length. Application of the natural structure of the continental margin method sometimes results that the continental shelf may extend beyond 200 nautical miles. The coastal State in this maritime zone has sovereign rights for the purpose of exploring and exploiting its natural resources, while third countries are entitled to lay submarine cables and pipelines, but in order to determine their directions, third States has to obtain the consent of the coastal State.
The high seas extends beyond the outer limits of the Exclusive Economic Zone and it embraces a water column above the seabed, sea surface and the air space. The high seas is a zone where neither one State has an exclusive jurisdiction over it, since it is opened for both coastal and landlocked States. Therefore, all countries of the world have guaranteed freedom of navigation, freedom of overflight, freedom to lay submarine cables and pipelines, freedom to construct artificial islands and other installations (if they are in accordance with the basic principles of the international law), while freedom of fishing and scientific research are subject to certain restrictions.
The Area as a maritime zone is a specific legal question. It actually represents the seabed and subsoil of the high seas, but decreased by the continental shelf of the coastal State to its maximum breadth. The Area is accessible to all States for use exclusively for peaceful purposes, and the activities in the Area shall be in accordance with the Convention, the principles of the United Nations Charter and other principles of the international law. Activities in the Area shall be carried out for the interests of maintaining peace and security, improving international cooperation and mutual understanding.
Even though the Convention has strictly defined maritime zones and their breadth, determination of the maritime zones in practice could be even more complex issue. The International Tribunal for the Law of the Sea, based in Hamburg is entitled to discuss all disputes related to the competence of the State, determining the boundaries of the marine zones, and many other issues related to the International Law of the Sea.
Rothwell and Stephens, The International Law of the Sea, Oxford and Portland, Oregon, 2010
VD Degan, International Law, Faculty of Law, University of Rijeka, Rijeka 2000 years
1982 United Nations Convention on the Law of the Sea, adopted on 10 December 1982 and entered into force on 16
 Rothwell and Stephens, The International Law of the Sea, Oxford and Portland, Oregon, 2010, page 1.
 1982 United Nations Convention on the Law of the Sea, adopted on 10 December 1982 and entered into force on November 16, 1994. Bosnia and Herzegovina is a State Party since 12 January 1994, Republic of Serbia since 12 March 2001, Republic of Croatia since 05 April 1995 and Montenegro since 23 October 2006.
 Before the explanation of the territorial sea, it has to be stated that International Law of the Sea recognize the zone of internal waters. Landward side of the baseline of the territorial sea form part of the internal waters of the State. For instance, the ocean bays, the historical waters, the historical bay, or the archipelagic waters may belong to the internal waters.
 V. D. Degan, Međunarodno pravo, Pravni fakultet Sveučilišta u Rijeci, Rijeka 2000, page 656.
 Ships of all States enjoy the right of innocent passage through the territorial sea.
 There are several ways of determining baselines. For instance, the low water line, the straight baselines or the archipelagic straight line.
 1982 United Nations Convention on the Law of the Sea, adopted on 10 December 1982 and entered into force on November 16, 1994, Article 33.
 This means if a State determines that the length of the territorial sea is 12 nautical miles, and then Exclusive Economic Zone is 188 nautical miles, as it continues to the outer limits of the territorial sea.
 Such as oil, gas, and other mineral resources.
 In this case, the coastal State is obliged to inform the Commission of the Limits of the Continental Shelf.
 1982 United Nations Convention on the Law of the Sea, adopted on 10 December 1982 and entered into force on November 16, 1994, Article 77 and 79.
 Ibid, Article 87.
 Ibid, Article 138.
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