MARITIME JURISDICTION AREAS: LEGAL REGIME AND PRINCIPLES OF DELIMITATION IN INTERNATIONAL LAW

I. INTRODUCTION

Seas cover a large portion of the Earth's surface and are strategically important areas for transportation, trade, energy, fishing, security, communication, scientific research, and environmental protection. However, the legal regime of the seas differs from the sovereignty regime of the land and exhibits a multi-layered structure. The powers that states possess in the seas change in nature and scope as the distance from the coast increases; different legal regimes emerge, ranging from full sovereignty to limited control powers, from sovereign rights to freedoms that all states can enjoy.

The aim of this study is to systematically examine the main maritime zones accepted in international maritime law; to determine the scope of sovereignty, sovereign rights, and jurisdiction of coastal states in these zones; and, in particular, to explain the fundamental principles applied in delimitation disputes arising between states with opposite or adjacent coasts.

This study will first examine the historical development and fundamental sources of maritime law; then, the baselines used in measuring maritime areas, internal waters, territorial waters, contiguous zone, continental shelf, exclusive economic zone, high seas, and international seabed will be studied. Subsequently, the application of the principles of equity, equidistance, relevant geographical conditions, and proportionality in delimiting maritime zones will be explained; and the three-stage delimitation method developed by international courts will be evaluated.

B. Historical Development of Maritime Law

In the classical period of international law, the legal regime of the seas was primarily shaped around two fundamental ideas. The first was the concept of "freedom of the high seas," or mare liberum in Latin, which argued that the seas could not be claimed by any single state and should be open to the use of all states. The second approach was mare clausum , or "closed seas," which argued that some states could establish ownership or exclusive sovereignty over maritime areas

For a long time, the prevailing approach in international law was that coastal states should exercise sovereignty only over a narrow strip of sea adjacent to their coasts, while areas beyond this were considered open to all states. The United Nations also explains this historical development by pointing to the principle of "freedom of the sea," where states initially exercised jurisdiction over a narrow zone of sea near their coasts, and the seas beyond this were open to all states.

However, particularly since the mid-20th century, the increasing economic value of natural resources in the seas, the intensification of offshore fishing, the exploitation of oil and natural gas resources on the seabed, and technological advancements have rendered the classical concept of freedom insufficient. Coastal states have begun to demand broader rights over natural resources near their coasts; concepts such as the width of territorial waters, continental shelf, fishing zones, and exclusive economic zone have developed.

In this process, the 1958 Geneva Conventions on the Law of the Sea constituted an important step, but comprehensive agreement could not be reached on fundamental issues such as the breadth of territorial waters and the legal status of the deep seabed. As a result of the Third United Nations Conference on the Law of the Sea, which lasted approximately nine years, the United Nations Convention on the Law of the Sea was adopted on December 10, 1982, and entered into force on November 16, 1994.

The 1982 United Nations Convention on the Law of the Sea is often referred to in legal doctrine as the "constitution of the seas" because it addresses different uses of the sea and the legal status of maritime areas within a single comprehensive framework. The Convention has established a holistic legal system encompassing maritime jurisdiction, marine environmental protection, scientific research, seabed resources, and dispute resolution.

C. Fundamental Sources of Maritime Law

The principal written source of international maritime law is the 1982 United Nations Convention on the Law of the Sea. The Convention regulates fundamental institutions of maritime law, ranging from territorial waters and the contiguous zone to the exclusive economic zone, the continental shelf, the high seas, and the international seabed.

However, UNCLOS is not the sole source of maritime law. International customary law is of great importance, especially for states not party to the Convention. It is accepted in international judicial decisions that some rules regulated in UNCLOS also acquire the character of customary law. The maximum width of territorial waters, the automatic creation of rights over the continental shelf, and the need to reach an equitable conclusion in maritime delimitation can be considered in this context.

The decisions of the International Court of Justice, the International Tribunal for the Law of the Sea, and arbitration courts also play a decisive role in the development of maritime law. These decisions particularly clarify the content of concepts such as "equitable settlement," "relevant coasts," "relevant area," "relevant conditions," "the reflection of coasts on the sea," and "disproportionality control.".

Turkey is not a party to the 1982 United Nations Convention on the Law of the Sea. Türkiye's current international declarations also explicitly maintain its status as a non-party to the UNCLOS. Nevertheless, Turkey is bound by the rules contained in the UNCLOS that have acquired the status of international customary law, within the framework of the general binding nature of customary law.

II. LINES USED AS A BASIS FOR DETERMINING MARITIME JURISDICTION AREAS

A. Mainline Concept

The baseline is the legal starting line from which the outer boundaries of maritime zones such as territorial waters, contiguous zone, exclusive economic zone, and continental shelf are measured. Therefore, determining the baseline directly affects the geographical scope of a coastal state's maritime zones.

The baseline can be considered the "zero point" from which a coastal state begins measuring its maritime areas. However, the baseline does not always perfectly follow the physical appearance of the coastline. Depending on the geographical structure of the coast, a normal baseline, a straight baseline, or a combination of both methods may be used.

B. Normal Mainline

According to Article 5 of the UNCLOS, the normal baseline is the low water line along the coast as shown on large-scale nautical charts officially recognized by the coastal state. The low water line refers to the coastline reached by the sea at the lowest tide.

In cases where the coastline is regular and not excessively indented, the basic method is the normal baseline. The width of the sea area is measured from this low waterline.

The normal baseline is the closest measurement method to geographical reality because it is based on the natural shape of the coastline. However, tidal movements, coastal erosion, coastal landfills, and changes in sea level can cause this line to change over time.

C. Straight Main Line

According to Article 7 of the UNCLOS, where the coastline is deeply indented or where there is a close chain of islands along the coast, straight baselines can be drawn by connecting suitable points.

The straight baseline method relies on connecting specific points on or near the coast with straight lines, rather than tracing all the small indentations and protrusions of the coastline. As a result of applying this method, some sea areas on the land side of the straight baseline may fall under the internal waters regime.

However, the authority to draw straight baselines is not unlimited. The lines must not deviate significantly from the general direction of the coast, and the maritime areas within the lines must be sufficiently connected to the mainland. Straight baselines cannot be applied in a way that cuts through another state's territorial waters from the open sea or its exclusive economic zone.

With regard to archipelago states, the UNCLOS also regulates archipelagic baselines. However, not every state with islands in front of its coast is considered an archipelagic state. The archipelagic state regime is primarily intended for states consisting entirely of one or more archipelagos.

D. Bays, Harbors and River Mouths

Special rules apply to bays, harbors, river mouths, and low water elevations when determining the coastline.

In legal terms, drawing a closure line at the mouth of a bay requires observing the semi-circle test stipulated in the UNCLOS and, as a rule, the maximum limit of 24 nautical miles. The outermost permanent port facilities, which form an integral part of the port system, can also be considered part of the coastline.

In contrast, artificial islands and offshore structures located separately from the coast do not constitute baseline points like natural land territory. Artificial islands do not have their own territorial waters, and their existence does not affect the delimitation of territorial waters, exclusive economic zones, or continental shelf boundaries.

E. Inland Waters

Internal waters are the sea areas that lie on the land side of the baseline. Ports, legally closed bays, river mouths, and certain sea areas on the land side of straight baselines may be considered internal waters.

The jurisdiction of a coastal state over its internal waters is, as a rule, as extensive as its sovereignty over its mainland territory. The state may regulate the entry of foreign vessels into its ports, require permission for entry, or refuse entry under certain conditions. There is no general right of innocent passage in internal waters.

The exception to this is when an area that was not previously considered inland waters becomes inland waters as a result of drawing a straight baseline. According to Article 8 of the UNCLOS, in such a case, the right of innocent passage previously enjoyed by foreign vessels may continue.

III. MARITIME AREAS SUBJECT TO NATIONAL SOVEREIGNTY

A. Territorial Waters

1. Legal Status and Scope

Territorial waters are the sea zone adjacent to the mainland and internal waters of a coastal state. The sovereignty of a coastal state extends to its territorial waters, the airspace above them, the seabed, and the subsoil.

According to Article 3 of the UNCLOS, each state has the right to determine the width of its territorial waters up to a maximum of 12 nautical miles from the baseline. The outer limit of the contiguous zone may reach a maximum of 24 nautical miles from the baseline.

Over territorial waters, there is not merely a "sovereign right," but direct sovereignty. However, the sovereignty of the coastal state is not absolute. The right of innocent passage for foreign vessels is one of the main limits on sovereignty over territorial waters recognized by international law.

In Türkiye, the general width of territorial waters is 6 nautical miles. However, the Territorial Waters Law allows for the determination of wider territorial waters in certain seas. In practice, 12 nautical miles are applied in the Black Sea and the Mediterranean, while 6 nautical miles are applied in the Aegean Sea. The geographical features of the Aegean Sea and the proximity of the opposing coasts make the issue of the width of territorial waters one of the main points of contention between Türkiye and Greece.

2. Delimitation of Territorial Waters Between Opposite or Adjacent Coasts

The delimitation of territorial waters between states with opposite or adjacent coasts is, as a rule, carried out by the method of equidistance or the median line. According to Article 15 of the UNCLOS, unless historical rights or other special circumstances require a different delimitation, neither state may extend beyond the median line without the consent of the other state.

Here, the concept of "special circumstances" may include factors such as the shape of the coastline, the presence of islands very close to the coast, navigation routes, or historical rights. The median line rule provides a stronger starting point for delimiting territorial waters compared to continental shelf and EEZ delimitations.

B. Right of Innocent Passage

According to Article 17 of the UNCLOS, ships of all states, whether coastal or land-locked, have the right of innocent passage through the territorial waters of a foreign state. The passage must be continuous and expeditious. Stopping and anchoring are only considered part of the passage in cases such as those necessary for normal navigation, force majeure, danger, or an obligation to provide assistance.

Passage is innocent as long as it does not prejudice the peace, order or security of the coastal state. The innocent nature of passage may be compromised if a foreign vessel uses or exercises weapons, gathers intelligence, engages in propaganda, lands or takes off aircraft or military equipment, engages in fishing, causes serious pollution, conducts research or surveying, or engages in any other activity not directly related to the passage.

The coastal state may take the necessary measures to prevent innocent passage. Furthermore, if necessary for the protection of its security, it may temporarily suspend innocent passage in certain areas of its territorial waters, provided that it does not discriminate and gives prior notice. Conversely, the coastal state may not make regulations that effectively eliminate the right of innocent passage or create discrimination among vessels.

Submarines and other underwater vehicles are required to stay on the surface and display their flags when passing through territorial waters. Nuclear-powered vessels or those carrying hazardous materials are obliged to carry the necessary documents as stipulated in international agreements and comply with special regulations.

C. Adjacent Area

The contiguous zone is the maritime area beyond the territorial waters where the coastal state exercises limited control over certain matters. According to Article 33 of the UNCLOS, the contiguous zone cannot exceed 24 nautical miles from the baseline used to measure territorial waters.

The powers of a coastal state in the contiguous zone differ from its sovereignty over its territorial waters. The state does not possess general legislative, executive, or judicial authority in this area. It can only conduct necessary inspections to prevent violations of customs, finance, immigration, and health legislation within its territory or territorial waters, or to punish violations that have occurred in these areas.

The contiguous zone is, in most cases, also part of the exclusive economic zone. Therefore, the coastal state's powers in the contiguous zone and its sovereign rights in the EEZ can be exercised within the same geographical area, but based on different legal grounds.

IV. MARITIME AREAS SUBJECT TO SOVEREIGN RIGHTS AND FUNCTIONAL POWERS

A. Continental Shelf

1. Concept and Legal Definition

The continental shelf refers to the rights of a coastal state over the seabed and subsoil beyond its territorial waters. According to Article 76 of the UNCLOS, the continental shelf encompasses the seabed and subsoil extending along the natural extension of the coastal state's land territory to the outer limit of the continental margin. Where the continental margin does not reach 200 nautical miles, the continental shelf legally extends to at least 200 nautical miles.

As a result of this regulation, the continental shelf has become both a geological and a legal concept. Even if a coastal state's continental margin is geographically shorter than 200 nautical miles, it may legally have continental shelf rights up to 200 nautical miles.

Where the continental margin extends beyond 200 nautical miles, the coastal state may claim a continental shelf beyond 200 miles within the framework of the technical formulas and maximum limits in Article 76 of the UNCLOS. Scientific and technical data must be submitted to the Continental Shelf Boundaries Commission in determining these outer limits.

2. Nature of Continental Shelf Rights

A coastal state has exclusive sovereign rights to explore its continental shelf and exploit its natural resources. These rights are exclusive; even if the coastal state does not conduct exploration or exploitation on its continental shelf, another state cannot carry out these activities without its explicit consent.

Rights over the continental shelf arise automatically and from the outset. It is not necessary for the coastal state to declare, actually occupy, or conduct activities on its continental shelf in order to acquire these rights.

Continental shelf rights relate only to the seabed and subsoil. The legal status of the water mass above the seabed is not affected. Therefore, the waters above the continental shelf may be subject to the Exclusive Economic Zone (EEZ) or the High Seas regime, depending on their distance from the coast.

The natural resources of the continental shelf include non-living resources such as oil, natural gas, and minerals located on and under the seabed, as well as living organisms that remain attached to the seabed during the harvesting process or are in continuous physical contact with the seabed.

3. Extension of the Continental Shelf Beyond 200 Nautical Miles

The outer continental shelf may come into question if the natural extension of a coastal state's continental margin extends beyond 200 nautical miles. However, the area that a coastal state can claim is not unlimited. The UNCLOS defines the outer limit of the continental shelf with technical criteria such as 350 nautical miles from the baseline or 100 nautical miles from the 2,500-meter depth line.

The task of the Continental Shelf Boundaries Commission is to evaluate scientific and technical data submitted by coastal states and to make recommendations on external boundaries. The Commission does not delimit maritime boundaries between states or resolve overlapping sovereignty claims.

B. Exclusive Economic Zone

1. Legal Nature and Scope

The exclusive economic zone (EEZ) is a maritime area beyond and adjacent to territorial waters, subject to its own legal regime. The EEZ cannot exceed 200 nautical miles from the baseline.

The Exclusive Economic Zone (EEZ) is neither a continuation of territorial waters nor entirely the open sea. In this area, while coastal states have sovereign rights over certain economic activities and resources, other states continue to enjoy certain freedoms, such as freedom of navigation, flights, and the laying of submarine cables and pipelines.

Unlike territorial waters, the Exclusive Economic Zone (EEZ) does not have full sovereignty. The powers of the coastal state are limited to economic and functional matters as defined in the Convention.

2. Rights of the Coastal State in the EEZ

The coastal state has sovereign rights to explore, exploit, protect, and manage the living and non-living natural resources found on the seabed, subsoil, and in the water body above within its Exclusive Economic Zone (EEZ).

These rights include fishing resources, living resources in the body of water, oil and natural gas, minerals on the seabed, and energy production from water, currents, and wind.

The coastal state is also within the EEZ;

• The construction and use of artificial islands, facilities, and structures,
• Marine scientific research,
• Protection and conservation of the marine environment

Coastal states have jurisdiction over these matters. Article 56 of the UNCLOS requires coastal states to observe the rights and obligations of other states appropriately when exercising these powers.

Coastal states may take measures such as boarding, inspecting, seizing, and initiating legal proceedings against foreign vessels to ensure compliance with fishing legislation within their Exclusive Economic Zone (EEZ). However, there are limitations, such as the prompt release of vessels and crew upon provision of security, and the prohibition of imprisonment for fishing violations unless otherwise agreed.

3. Rights of Other States in the EEZ

All states, whether or not they have a coastline in the EEZ, enjoy freedom of navigation and flight, the right to lay submarine cables and pipelines, and other lawful uses of the sea in connection with these freedoms.

However, the exercise of these rights is not unlimited. Other states must respect the rights and arrangements adopted by the coastal state in accordance with the UNCLOS. Similarly, the coastal state, while exercising its own powers, cannot unnecessarily impede the freedom of navigation and communication of other states.

The EEZ regime is fundamentally based on the idea of ​​striking a balance between the exclusive rights of the coastal state over natural resources and the freedom of navigation and communication of the international community.

4. Announcement of the Ministry of National Education

Unlike continental shelf rights, it is generally accepted that for the exercise of EEZ rights, the coastal state must explicitly accept or declare its EEZ regime. While continental shelf rights arise automatically, the EEZ is a maritime jurisdiction established by a legal act of the coastal state.

However, the declaration of an Exclusive Economic Zone (EEZ) does not automatically negate the rights of other states with adjacent or neighboring coastlines. In areas where maritime zones are narrower than 400 nautical miles, delimitation is necessary because the 200-nautical-mile claims of neighboring coastal states will overlap.

C. Differences Between the Continental Shelf and the EEZ

Although the continental shelf and the Exclusive Economic Zone (EEZ) often cover the same geographical area, they are legally distinct entities.

The continental shelf relates only to the seabed and subsoil. The Exclusive Economic Zone (EEZ), on the other hand, encompasses the seabed, subsoil, and the water body above it. Therefore, rights relating to living resources in the water body, such as fisheries, are based on the EEZ regime, while rights relating to seabed resources such as oil and natural gas can be assessed under both the EEZ and continental shelf regimes.

Continental shelf rights arise automatically without requiring a declaration. However, the Exclusive Economic Zone (EEZ) must be declared by the coastal state or established within its domestic law.

The continental shelf can extend beyond 200 nautical miles under certain geological and technical conditions. However, the Exclusive Economic Zone (EEZ) can never exceed 200 nautical miles.

Even if an Exclusive Economic Zone (EEZ) has not been declared, the continental shelf rights of the coastal state continue. Conversely, the declaration of an EEZ does not eliminate continental shelf rights on the seabed; the two regimes can complement each other in the same area.

V. INTERNATIONAL AREAS

A. High Seas

The high seas are the areas of the sea outside a state's internal waters, territorial waters, archipelagic waters, or exclusive economic zone. No state may claim sovereignty over any part of the high seas.

The high seas are open to the use of all states, whether they have a coastline or not. The freedoms of the high seas primarily include:

• Navigation,
• Flight,
• Submarine cable and pipeline laying,
• Establishing artificial islands and facilities in accordance with international law,
• Fishery,
• scientific research

It includes their freedoms.

These freedoms must be exercised while respecting the right of other states to enjoy the high seas. Freedom of the high seas does not mean an area without oversight or the application of the law.

As a rule, ships sailing on the high seas are subject to the exclusive jurisdiction of the state whose flag they fly. Each state is obliged to establish effective administrative, technical, and social control over ships flying its flag.

The flag state's exclusive jurisdiction has exceptions in cases such as piracy, slave trade, unauthorized broadcasting, stateless vessels, and hot pursuit. In these cases, warships of other states may exercise certain powers of surveillance or intervention.

B. International Seabed Area: “Area”

In the UNCLOS, "Area" is defined as the seabed, ocean floor, and subsoil extending beyond national jurisdiction. While the body of water above the Area is subject to the high seas regime, the seabed and its resources are subject to a separate legal regime.

The area and its resources are considered "the common heritage of humanity". No state can claim sovereignty or sovereign rights over any part of the area or its resources. States, individuals, and companies can only use the resources in the area within the framework of the system established by the UNCLOS and the International Seabed Authority.

The International Seabed Authority is an autonomous international organization established under the UNCLOS and the 1994 Implementing Agreement. Its mandate is to regulate activities related to mineral resources in the Area for the benefit of all humanity and to protect the marine environment from the harmful effects of deep-sea activities.

The area encompasses a significant portion of the seabed of the world's oceans. As of 2026, the International Seabed Authority has 172 members, including 171 states and the European Union. However, commercial-scale deep-sea mining has not yet commenced in the area; existing activities remain primarily in the exploration and scientific evaluation phases.

Deep-sea mining offers economic opportunities in terms of polymetallic nodules, cobalt-rich crusts, and seabed sulfides, but it is also subject to serious legal and environmental debates due to the potential for irreversible damage to marine ecosystems.

VI. DELIMITATION OF MARITIME JURISDICTION AREAS

A. The Emergence of the Need for Restriction

The right of a coastal state to have maritime jurisdiction and the precise demarcation of these areas with respect to neighboring states are two different legal matters.

A state's continental shelf and Exclusive Economic Zone (EEZ) rights stem from its coastal geography. However, when the maritime area claims of states with opposite or adjacent coasts overlap, it is necessary to determine which state owns these areas through delimitation.

Especially in semi-enclosed seas, areas with a high concentration of islands, and where the distance between states is less than 400 nautical miles, claims to the 200-nautical-mile Exclusive Economic Zone (EEZ) and continental shelf inevitably overlap.

B. The Principle of Equitable Resolution

Article 74 of the UNCLOS provides for the delimitation of the Exclusive Economic Zone (EEZ), while Article 83 provides for the delimitation of the continental shelf between states with adjacent or contiguous coasts through an agreement in accordance with international law and in a manner that achieves an equitable result.

The agreement does not necessarily require the application of the equidistance method or a specific mathematical formula in determining the boundary. The fundamental obligation is to reach an equitable result.

Equity is not an abstract concept of justice that can freely vary depending on the political or economic status of the parties. International judicial bodies apply equity within the framework of legal rules and objective geographical criteria.

C. The Principle of "Black Sea Domination"

The legal source of maritime jurisdiction is land territory. A state's right over its maritime area stems from its possession of a coastline and the legal projection of that coastline into the sea.

Therefore, when delimiting boundaries, international courts primarily identify the relevant coastlines and the relevant maritime area where the maritime extensions of these coastlines overlap.

Claims that are not connected to the coast and are based solely on maritime activities, historical research, or economic expectations do not, by themselves, create a maritime jurisdiction.

D. Equidistant and Midline

The equidistance line is the line along which every point is equidistant from the closest points on the baselines of the two states. In the context of opposite coasts, this line is often referred to as the "median line".

In current international jurisprudence, the equidistant line is used as the starting point in most delimitation decisions. However, equidistant is not the final boundary. The line may be altered if the geographical structure of the coast leads to an unfair outcome.

E. Three-Stage Delimitation Method

The International Court of Justice, particularly since its 2009 decision in the Romania–Ukraine Black Sea maritime delimitation case, has developed a three-stage methodology. This methodology has subsequently been applied by the ICJ, ITLOS, and arbitration tribunals in numerous disputes.

1. Drawing the Temporary Equidistant Line

In the first stage, a geometric and objective provisional equidistant line is drawn using suitable baseline points on the respective coasts of the parties.

At this stage, equity, coastal lengths, or other specific conditions are not yet assessed. The aim is to establish a neutral and mathematical starting point for delimitation.

2. Evaluation of Relevant Conditions

The second stage examines whether the temporary equidistant line produces an unfair result. If equity warrants it, the line is shifted or corrected.

The relevant conditions are determined according to the specifics of each dispute. In practice, the main relevant conditions are as follows:

• The concave or convex structure of coastlines,
• Cutting off a state's access to the sea from its coast
• The location and size of the islands,
• The significant difference between the relevant coastline lengths,
• The excessive influence of small geographical formations close to the coast on the line,
• The general geographical structure of the region,
• Rights of third states.

Economic conditions, the distribution of natural resources, population, or the level of development of states are, as a rule, not considered independent criteria for determining delimitation. However, it is possible to consider exceptional circumstances, such as when a delimitation would completely deprive a state of its existing and vital natural resources.

3. Disproportionality Control

In the third stage, it is checked whether the corrected boundary line creates a clear and significant disproportion between the respective coastal lengths of the parties and the maritime areas allocated to them.

At this stage, a mathematical equation is not sought. The assessment focuses on whether there is a significant and inexplicable imbalance between the ratio of coastline length to the ratio of sea area.

The principle of proportionality is not, in itself, a method of limitation. It is a final control tool that verifies the fairness of the limit obtained in the first and second stages.

The ICJ notes that the three-stage method is not explicitly mandated in the UNCLOS, but has been developed through court case law because it is based on objective geographical criteria and provides predictability.

F. The Influence of Islands on Delimitation

According to Article 121 of the UNCLOS, naturally formed land masses surrounded by water and above the water during high tide are considered islands. As a rule, islands, like mainland territory, can form territorial waters, a contiguous zone, an Exclusive Economic Zone (EEZ), and a continental shelf. In contrast, rocky islets that cannot sustain human settlement or their own economic life do not have an EEZ or a continental shelf.

However, the fact that an island can, in principle, generate maritime area does not necessarily mean that it will have the same effect as the mainland in terms of delimitation.

International courts sometimes grant limited effect, particularly to small islands and those close to the mainland of the opposing party, in some cases only leaving territorial waters or not taking the island into account in the establishment of the provisional equidistant line.

When determining the impact to be given to the islands;

• The size of the island,
• Population and economic life,
• Distance from the mainland,
• Its proximity to the coast of the other state,
• Coastal lengths,
• The island's disruptive effect on the delimitation line,
• Whether a state cuts its coastal projection

Factors such as these are evaluated.

Therefore, there is no absolute rule in international law that "islands have full effect in all cases" or "islands do not constitute a continental shelf in any way." Each island is evaluated within its specific geographical context.

G. The Length of the Coastline and the Advantage of Geography

The fundamental criterion for maritime delimitation is geography. The length, orientation, relationship to each other, and the projections of the relevant coastlines into the sea are central to the delimitation process.

However, coastal lengths do not directly necessitate an equal distribution of maritime areas. The ratio of coastal length is particularly important in the final assessment of disproportionality.

The concave nature of the coastline can cause the provisional equidistant line to confine the relevant state to a narrow area towards the sea, interrupting the coastal projection. International courts may correct the equidistant line by accepting this "interruption effect" as a relevant condition.

H. Provisional Arrangements and the Obligation Not to Aggravate the Dispute

According to Articles 74 and 83 of the UNCLOS, until a delimitation agreement is reached, the parties should endeavor to make provisional practical arrangements in a spirit of understanding and cooperation, and should avoid actions that would jeopardize or hinder the achievement of a final agreement.

In this context, states;

• We can establish joint development zones,
• They can share oil and natural gas revenues,
• We can organize fishing activities together,
• We can conduct joint scientific research,
• It can temporarily restrict exploration and drilling activities.

Such arrangements do not prejudice the final limitation. A provisional cooperation agreement by one party does not imply acceptance of the other party's claim to sovereignty.

VII. DISPUTE RESOLUTION MECHANISMS

A. Negotiation

The fundamental method for delimiting maritime zones is agreement between the relevant states. Articles 74 and 83 of the UNCLOS also stipulate that an equitable solution should primarily be reached through an agreement based on international law.

A border determined through negotiation is, as a rule, considered equitable because it is based on the mutual consent of the parties. However, the agreement cannot affect the existing or potential rights of third states.

B. Mediation, Conciliation and Arbitration

The parties may seek mediation from a third state or international organization. Under UNCLOS, there are also voluntary or mandatory conciliation mechanisms for specific disputes.

Arbitration is a frequently used method in maritime law disputes. Arbitration tribunals established under Annex VII of the UNCLOS can handle general maritime law disputes; while special arbitration under Annex VIII can handle technical disputes such as those related to fisheries, environmental protection, scientific research, and navigation.

C. International Court of Justice

The International Court of Justice can only rule if the States parties to the dispute accept its jurisdiction. This acceptance may occur through a special agreement, a jurisdictional clause in a treaty, or a mandatory declaration of jurisdiction made under Article 36, paragraph 2, of the Statute of the ICJ.

The Court has shaped the development of maritime delimitation law in numerous cases, including the North Sea Continental Shelf, Libya–Malta, Qatar–Bahrain, Romania–Ukraine, Nicaragua–Colombia, Peru–Chile, Somalia–Kenya, and many others.

D. International Tribunal for the Law of the Sea

The International Tribunal for the Law of the Sea is a permanent international judicial body established by the UNCLOS and headquartered in Hamburg. The Tribunal can decide on disputes relating to the interpretation and application of the Convention.

ITLOS's jurisdiction covers disputes relating to maritime delimitation, the prompt release of detained vessels and crew, interim measures, and international seabed activities.

In the Bangladesh–Myanmar case, ITLOS delimited the continental shelf both within 200 nautical miles and, under certain conditions, beyond 200 nautical miles, applying a three-stage method. This decision established significant precedent regarding the delimitation of the outer continental shelf.

E. The Mandatory Dispute Resolution System of the UNCLOS

Chapter XV of the UNCLOS regulates the obligation of states to settle disputes concerning the interpretation or application of the Convention peacefully. States may choose between ITLOS, ICJ, Annex VII arbitration, or Annex VIII special arbitration for specific technical issues.

If the parties have not agreed on the same procedure, arbitration under Annex VII generally applies. However, with regard to maritime delimitation, historical gulfs, military activities, and certain law enforcement activities, states may choose to remain outside the compulsory jurisdiction under Article 298 of the UNCLOS.

Since Turkey is not a party to the UNCLOS, it is not subject to the mandatory dispute resolution mechanisms in Chapter XV of the Convention as a State party. For Türkiye to bring a maritime delimitation dispute to the ICJ, ITLOS, or arbitration requires a special jurisdiction agreement with the relevant State or another legal basis for consent.

EVALUATION

Maritime law establishes a delicate balance between the maritime powers of a coastal state and the international community's interests in navigation, communication, and the exploitation of natural resources. Within this system, internal and territorial waters are subject to the sovereignty of the coastal state, while control over the contiguous zone is limited to specific areas. The continental shelf and exclusive economic zone, however, do not represent full sovereignty, but rather exclusive sovereign rights and specific functional powers related to the exploration and exploitation of natural resources. The high seas and the seabed beyond national jurisdiction are international areas that cannot be subject to the unilateral sovereignty of any single state.

The extent of maritime jurisdiction is as important as how it is delimited between states with opposite or adjacent coastlines. In current international legal practice, the primary aim of delimitation is not to achieve mechanical equality, but to reach an equitable outcome by taking into account the geographical characteristics of the coastlines and the relevant circumstances of the specific case. Accordingly, the establishment of a provisional equidistant line, its adjustment according to relevant conditions, and the subjection of the resulting outcome to disproportionality review have become established practices of international judicial bodies.

The influence of islands on delimitation cannot be determined in advance and in an abstract manner. While islands can, as a rule, generate maritime jurisdiction, their size, location, proximity to the mainland coasts of the opposing state, and their disruptive effects on delimitation can mean that their influence may be full, limited, or in some cases, limited only to territorial waters, depending on the specific circumstances of the case.

In conclusion, the determination and delimitation of maritime zones is a complex legal process that cannot be reduced solely to nautical mile calculations or a single geographical element. Accurate baseline identification, differentiation of the legal characteristics of maritime areas, delineation of the coastal state's jurisdiction, and consideration of the rights of neighboring states are necessary. Therefore, resolving disputes, particularly those arising in semi-enclosed seas, through negotiation, provisional joint arrangements, and, where necessary, international judicial or arbitration mechanisms, rather than unilateral actions, is the most appropriate method for ensuring legal security at sea and regional stability.