An Overview of Maritime Delimitation in International Law:

By- Devi Sree Durgampudi


The maritime delimitation in international law is a subject in international with great political and technical relevance with inherent complexities. Maritime Delimitation has historical, political, geographical, economic, legal and environmental factors that are to be considered while determining the boundaries these factors are generally inalienable in nature and basic elements for determination. There had been huge development of Maritime Delimitation law over the decades. The fight for the valuable resources is never ending and through the major conventions such as UNCLOS, Convention on Territorial Sea and the Contiguous Zone, 1958, Convention on the Continental Shelf, 1958 and other derivatives from the customary law or treaties; ICJ had played an undeniable role in the development of principles relating to the Maritime Delimitation. In this article Maritime Delimitation will be expounded taking into consideration the developments throughout these years.

  1. Basic Principles of Maritime Zones

The national jurisdiction over the waters would regulate the subject matters that are related to the resources of the waters. The Costal States generally have different powers over the various zones of the ocean, which would determine their rights and jurisdiction. The categorisation of maritime zones as recognised under the UNCLOS are the internal waters, Territorial Sea, Contiguous Zone, EEZ, Continental Shelf and High Seas. The maritime zones are generally calculated from the baselines.


Baseline is generally the line that is followed along the coastline, from where the various maritime zones and the jurisdictions are measured. The waters that are within the baseline would be called as internal waters, they are basically waters that are within the baselines they might be bays, ports, rivers, harbours and many more. The basic principle is that the internal waters are subject to the full sovereignty of the coastal state and they may regulate the access to the ports and impose conditions under the Article 25(2) of UNCLOS. All maritime zones are measured seawards from the baseline. In case there is an indentation of the land there might be straight line that is drawn along the coast. If there is an island for that is falling near the coast and it belongs to the coastal state then the baseline would include the island, the baseline would be drawn from the mainland to the outer edge of the island area of sea would also be internal sea.

Territorial Sea:

The Territorial Sea extends from the 12nm our form the baseline of the land, the territorial sea would have sovereignty over the Territorial Sea and the air space above it, under Article 21 of UNCLOS the coastal state can act with regards to the matters of the traffic or safety or fishing and the conservation of environment and with regards to the immigration laws along with customs. The right to innocent passage is provided under UNCLOS from Article 17 to 32 in the territorial sea, where it would allow the navigation, under Article 19 of UNCLOS in case the non-innocent acts such as exercise of any weapons or gathering of an information, fishing activities or any other survey activities, or activities that are not having any direct bearing with regards to the passage, there might be a criminal liability. The innocent passage would not contain hovering except for the cases of distress or recue etc... As provided under Article 18 of UNCLOS. Article 27 of UNCLOS provides the coastal state wouldn’t in general exercise criminal jurisdiction but if there are any crimes that would disturb the peace of the Coastal state or territorial sea then it could exercise the criminal jurisdiction.

Contiguous Zone, EEZ and the Continental Shelf

The contiguous zone extends out to 12nm to 24 nm, this zone acts as a buffer from the infringement of the regulations or rights over the territorial sea. The EEZ is extended from the baseline to outwards of the Sea extended out to 200nm, the rights in this zone are extended to the exploring of natural resources, living and non-living, water column and sea bed inclusive of the sea bed and subsoil. Continental Shelf differs based on the geographical region, it can extend beyond 200nm of EEZ. The deep sea bed starts when the continental shelf ends. The High Seas or ABNJ are beyond the jurisdiction of Nations Sovereignty.

2. Principles relating to Maritime Delimitation Under Several Conventions:

In case two States that are opposite or adjacent towards each other, when they fail to reach an agreement for the extension of the territorial sea that is beyond the median line then the point of which is equidistant from the baselines nearest points where the breadth of the territorial sea of each of the two States is measured in accordance to Article 12(1) of Convention on Territorial Sea and the Contiguous Zone, 1958. According to the Convention on the Continental Shelf, 1958, Article 6, where there is a same continental shelf that is adjacent to the territories of two or more states where the coasts are placed in opposite direction to each other, it shall be determined with an agreement between them. In case there is no agreement, unless and until the boundary line of another is justified by special circumstances then the boundary is the median line where all the points which are equidistant from the nearest of the baselines where the breadth of the territorial sea of each State is to be measures. In case of absence of special circumstances then the line would be drawn based on the principle of equidistance. Article 15 of UNCLOS, states that where there are coasts of the two states are positioned either opposite or adjacent against each other, in case they fail to reach an agreement for the extending of the territorial sea beyond the median line every point which is placed equidistant from the nearest points of the baselines from where the territorial sea breadth would be calculated, neither of them would be entitled in case they fail to reach an agreement. However where is a historic title or any other special circumstance where the delimitation of the territorial sea which is at variance. And following the 1982 Convention, Article 12 of Geneva Convention on the Territorial Sea, 1958, provides that in case of absence of any agreement and in failure of agreement between the party States. Neither of the States in dispute for the territorial sea between the states with the adjacent coasts or opposite coasts then neither of the States would extend the territorial sea that is beyond the median line where all the points are equidistant from the nearest point on the baselines from where the territorial sea is measured.

Article 74 and 83 of UNCLOS, the delimitation of a EEZ or for a continental shelf that is in between the States with opposite coasts or adjacent, would be through the effect of an agreement which is made on the basis of international law as under Article 38 of the Statute of the International Court of Justice for the achieving of equitable solution.

3. Rules of Maritime Delimitation:

Yoshifumi Tanaka defines Maritime Delimitation as the process of establishment of lines that would separate the ambit of jurisdiction of a coastal state over the maritime space where there would be a potential legal claim or title that would overlap with that of another state. In case of the boundary disputes the settlement for the legal disputes would be generally through an agreement, equidistance or of special circumstances.

Delimitation is a principle that is in relation to the territorial sovereignty, in case of involvement of the other nations the agreement would be required. Though the domestic law is valid, nay sort of unilateral delimitation would not be binding on the 3rd party State that is involved.

The following are few case laws where disputes of maritime delimitation had been referred to ICJ, which played a major role in the development of principles and jurisprudence of maritime delimitation in international arena.

Anglo-Norwegian Fisheries Case/ United Kingdom v Norway :

UK had requested the ICJ for the determination of the Norway’s claim over the territory of the extended sea and had prayed for the award to UK damages as compensation that have been incurred for the interference with UK’s fishing vessels with respect to the disputed waters. UK had claimed that the claims of Norway for the extent of waters is against to the international law. The question that was brought before the Court was to decide if Norway’s action of drawing the baseline form where it measured the territorial sea is legally acceptable.

The delimitation had been complicated due to the irregular coastline of Norwegian mainland, which was broken due to large and deeply indented by the seawards islands, islets, rocks, and reefs. The fish in this area had been exploited by Norwegian fishermen for many centuries. In response to British fishing vessels appearing off the Norwegian coast beginning in 1906, the Norwegian Government in the Royal Decree of 1935 drew straight baselines (up to 44 miles in length) with 48 fixed points on the mainland, islands, and rocks in the sea, enclosing a large area of water. The Kingdom of Norway claimed exclusive fishing rights within the adjoining zone, four sea miles (‘sm’) seaward from the baseline. While both parties agreed on the breadth of the fishery zone, the United Kingdom objected to the drawing of straight baselines from which the fishery zone was measured and maintained that, at least, such baselines should not exceed 10sm under international law. After the failure of consultations, the UK instituted proceedings before the ICJ against Norway on 28 September 1949.

UK had put forth the argument that the customary international law hadn’t allowed the length of the baseline to be drawn across the bay for it to be longer than 10 miles, this argument was not accepted by ICJ. Norway had alleged that the delimitation was in consistence with the principles of international law. ICJ had found that the water of Norwegian fjords were characterised as internal waters, the rocks and the reefs are an extension to the Norway’s, mainland. ICJ had observed that delimitation of territorial sea is a unilateral act and the validity is to be weighed on the basis of international law. First, baselines must not depart to any appreciable extent from the general direction of the coast. Second, the sea areas within the lines must be sufficiently closely linked to land formations. Finally, economic interest’s peculiar to a region clearly evidenced by long that is by consistent and uninterrupted, usage may be taken into account. In general, the delimitation needs to be within the bounds of what is moderate and reasonable. ICJ had concurred that the delimitation was a “long, consistent, and uninterrupted practice” by Norway

The criteria that the ICJ has set out is on the basis that the baselines must be reasonable and they are to follow the “general direction of the coast”

The Court had observed that the delimitation between the states that are having the opposite or adjacent coasts would not be effected by the unilateral decision of the one of either of the states. The delimitation in such cases are to be determined by the agreement that is made through by the following of negotiations that are conducted in good faith and with the genuine intention for the achieving of positive result.

North Sea Continental Shelf Cases (Germany v Denmark and Netherlands):

The North Sea Continental Shelf cases are brought to the ICJ which are based on several disputes that involved the agreement that are related to the States of Denmark, Netherlands and Germany, with regard to the delimitation of areas in the continental shelf which are having potential natural resources such as oil and gas. These were the very first cases that are concerning the delimitation of the maritime zones seawards of the territorial sea. The equidistance principle and the delimitation process are the main merits of this case. The coast of North Sea Coast (Germany) was in concave shape and the Denmark’s coast is in the form of convex shape. Due to this there was as possibility that Germany would receive a smaller part of the resources that are in relation between the two states, hence it has claimed for the determination of the coastline through the process of delimitation. It had wanted ICJ for the sharing of continental shelf with the portion of the States adjacent land size which it had claimed to be as just and equitable share and not by the principle of equidistance.

As the application of Article 6 would only leave Germany with small share of North Sea continental shelf,