Does Kastellorizo Generate a Full Maritime Zone? The Island Question and the Longest Coastline
Does Kastellorizo have a continental shelf and EEZ? Compare UNCLOS Article 121, island-effect case law, Greece's view and Türkiye's equity argument.
Why It Matters
Kastellorizo (Meis in Turkish) certainly generates a territorial sea; whether it also generates a full continental shelf and exclusive economic zone (EEZ) is the central unresolved question in the Eastern Mediterranean. Greece answers yes on the basis of UNCLOS Article 121, while Türkiye, which is not a party to that convention, argues that an island of about 10 sq km (4 sq mi) lying roughly 2 km (1.2 mi) from the Anatolian coast cannot cut off the projection of the mainland with the longest coastline in the region. No court has decided the point, so the answer depends on which legal framework and which delimitation method one accepts.
Background
The geography
Kastellorizo is the easternmost inhabited Greek island, with a population of under 1,000. It lies about 2 km (1.2 mi) from the Turkish town of Kaş. It is more than 500 km (310 mi) from the Greek mainland (Ankara cites roughly 580 km) and about 120 km (75 mi) from Rhodes. Türkiye has about 870 km (540 mi) of coastline facing the Eastern Mediterranean, the longest of any state in the basin.
What the law says
The 1982 UN Convention on the Law of the Sea (UNCLOS) sets out the main rules:
- Article 121(1)-(2): an island is a naturally formed area of land above water at high tide, and its territorial sea, contiguous zone, EEZ and continental shelf are determined like those of other land territory.
- Article 121(3): rocks that cannot sustain human habitation or economic life of their own have no EEZ or continental shelf.
- Articles 74 and 83: EEZ and continental shelf delimitation between states with opposite or adjacent coasts must be effected by agreement 'on the basis of international law' to achieve an 'equitable solution'.
- Limits: an EEZ and continental shelf extend up to 200 nautical miles (370 km) from baselines, but only where no neighbouring entitlement overlaps.
Because the Mediterranean is narrower than 400 nautical miles at most points, entitlements overlap almost everywhere, so the crucial question is not whether an island has a zone but how much of that zone survives delimitation.
What courts have done with islands
Article 121 sets out what an island is entitled to. Delimitation case law decides how far those entitlements prevail against a neighbour's coast. Widely cited precedents include:
| Case | Year | Treatment of the islands |
|---|---|---|
| North Sea Continental Shelf (ICJ) | 1969 | Stressed equitable principles and natural prolongation; rejected strict equidistance as mandatory |
| Anglo-French Channel Islands arbitration | 1977 | Channel Islands, close to the French coast, confined to a 12-nautical-mile enclave |
| Tunisia/Libya (ICJ) | 1982 | Kerkennah Islands given reduced (half) effect |
| Romania v. Ukraine (ICJ) | 2009 | Serpent Island given no effect on the continental shelf and EEZ line; three-stage method with a proportionality check |
| Bangladesh/Myanmar (ITLOS) | 2012 | St Martin's Island given no effect on the EEZ and continental shelf boundary |
| Nicaragua v. Colombia (ICJ) | 2012 | Small Colombian islands enclaved or given limited effect; the Court also stated that Article 121 reflects customary law |
The pattern is that tribunals recognise island entitlements in principle but frequently adjust or limit them where a small island sits near a larger mainland coast and would distort the result. None of these cases concerned Kastellorizo. The 1978 ICJ Aegean Sea Continental Shelf case between Greece and Türkiye ended with the Court finding that it lacked jurisdiction.
Short chronology of the Kastellorizo-related claims
- 2004 onward: Türkiye files continental shelf coordinates for the Eastern Mediterranean with the UN.
- 2003, 2007, 2010: Greek Cypriot administration concludes EEZ agreements with Egypt, Lebanon and Israel; Ankara objects, saying they disregard Turkish and Turkish Cypriot rights.
- 21 September 2011: Türkiye and the TRNC sign a continental shelf delimitation agreement.
- 27 November 2019: Türkiye and Libya's Tripoli-based government sign a maritime jurisdiction memorandum of understanding.
- 6 August 2020: Greece and Egypt sign a partial EEZ delimitation agreement.
- 18 March 2020: Türkiye registers the outer limits of its continental shelf with the UN.
- 16 April and 12 June 2025: Türkiye unveils its Marine Spatial Planning and has it registered with IOC-UNESCO.
For a wider comparison of how each coastal state draws the sea, see The Eastern Mediterranean Side by Side.
Key Players & Positions
Greece
Athens argues that UNCLOS, to which it has been a party since 1995, treats inhabited islands like any other land, so Kastellorizo is entitled to a continental shelf and EEZ. It says the dispute concerns only the delimitation of the continental shelf and EEZ and that the right forum is the International Court of Justice or another third-party mechanism. It rejects the view that the size of a mainland coast should override island entitlements. Greek officials point to the 2012 ICJ statement that Article 121 reflects customary law. Analysts note, however, that the 2020 Greece–Egypt agreement left Kastellorizo with a reduced effect rather than a full one, which shows that even Athens has accepted compromises in practice.
The Republic of Cyprus (Greek Cypriot administration)
Nicosia supports the Greek reading of island entitlements and relies on its 2003 agreement with Egypt and its other bilateral EEZ agreements. It rejects Turkish claims over areas it has licensed for hydrocarbon exploration.
The European Union
The European Council has repeatedly stated that UNCLOS reflects customary international law and that EU member states' maritime rights, including those of islands, must be respected. In December 2019 its conclusions held that the Türkiye–Libya memorandum infringes the sovereign rights of third states, does not comply with UNCLOS and cannot produce legal consequences for them. EU institutions describe this as solidarity with Greece and Cyprus. Ankara replies that the EU is a party to the dispute through its members, not a neutral adjudicator of delimitation.
Egypt, Libya and others
Egypt, a UNCLOS party, concluded its own delimitations with Cyprus (2003) and Greece (2020). Libya is divided between rival authorities, and the Tripoli-based side that signed the 2019 memorandum has been contested by eastern institutions. Neighbouring states largely avoid Kastellorizo-specific statements, which leaves the island's status mostly a bilateral question. The wider Cyprus context is covered in Cyprus Seen from Five Capitals.
Türkiye's Position
Ankara's position, as set out by the Turkish Ministry of Foreign Affairs and the Presidency, rests on the following points.
- Islands cannot cut off the projection of the mainland. According to the Turkish Foreign Ministry, a small island lying 2 km off Anatolia and about 580 km from its sovereign's mainland cannot generate maritime zones that block the natural prolongation of a mainland coast of about 870 km. Ankara cites the 1969 North Sea Continental Shelf judgment, which anchored the continental shelf in the natural prolongation of the land territory.
- Equity and proportionality govern delimitation. Ankara argues that delimitation between states with unequal coasts must produce an equitable result under customary law, and that the disparity between Anatolia's coastline and Kastellorizo's few kilometres is a relevant circumstance. It points to the Channel Islands, Serpent Island and St Martin's Island decisions as evidence that tribunals reduce island effect when it would distort the outcome.
- Türkiye is not bound by UNCLOS. Türkiye is not a party to the convention and has consistently objected to its provisions being applied against it. Ankara says it relies on customary international law and equity and considers it inappropriate to treat Article 121(2) as a rule of automatic full effect. It acknowledges the 2012 ICJ statement that Article 121 reflects customary law, but replies that the island regime defines entitlement, not the outcome of delimitation, and does not remove equitable adjustment.
- Turkish Cypriot rights and an inclusive process. Türkiye maintains that Turkish Cypriots are co-owners of the island of Cyprus with equal rights to offshore resources, a position reflected in the 2011 Türkiye–TRNC agreement. It points to President Erdoğan's 2020 call for an Eastern Mediterranean conference including all coastal states and Turkish Cypriots, and prefers negotiation among all coastal states over unilateral maps or judicial referral limited to Greece's chosen question.
- Registration of its position. Ankara cites its 2004 UN filings, the 27 November 2019 Libya memorandum, the 18 March 2020 outer limits registration and the 2025 Marine Spatial Planning registered with IOC-UNESCO on 12 June 2025 as the documentary record of its claims. The plan was unveiled on 16 April 2025 and presented as the first time Türkiye's position across the Black Sea, Aegean and Mediterranean was recorded with a UN body.
Türkiye also rejects the Seville Map, a study-based chart that Ankara says would confine its maritime jurisdiction to a narrow strip in the Gulf of Antalya and that gives Kastellorizo full effect. Detailed treatment is available in Regional Balance's explainer on the Seville Map. The Blue Homeland doctrine behind these claims is covered in Doctrine Review's guide to Eastern Mediterranean maritime jurisdiction.
Source Comparison
The two sides often use the same facts but weigh them differently. The table below contrasts typical framings.
| Issue | Greek / EU and many Western sources | Turkish official sources |
|---|---|---|
| Legal framework | UNCLOS, reflecting customary law, applies to all | Customary law and equity apply; Türkiye is not a UNCLOS party |
| Kastellorizo's entitlement | Full territorial sea, EEZ and continental shelf under Article 121(2) | Territorial sea at most; no cut-off of the mainland's projection |
| Distance and coast length | Often treated as secondary to sovereignty | Central: 2 km from Anatolia, about 580 km from Greece, against 870 km of mainland coast |
| Delimitation method | Median or equidistance line as the starting point | Equitable result, proportionality, relevant circumstances |
| Dispute resolution | ICJ or another third-party forum for the continental shelf and EEZ | Negotiation among all coastal states, including Turkish Cypriots |
| Seville Map | Academic study, sometimes cited as reflecting UNCLOS | Maximalist map that confines Türkiye to the Gulf of Antalya |
| Türkiye–Libya MoU | Violates third-state rights and ignores islands | Equitable agreement concluded under international law |
| 2025 IOC-UNESCO plan | Seen as contested unilateral mapping | Documented record of Türkiye's position with a UN body |
Readers comparing coverage should check whether an article distinguishes entitlement from delimitation, mentions Türkiye's non-party status, and cites the primary documents. Fuller comparisons are in The Worldlogue's analysis of islands and the continental shelf and Monitor of Nations on Blue Homeland. Our sourcing standards are set out in Editorial Principles and Primary Source Standards.
Key Terms & Related Guides
- Territorial sea: a coastal state's waters up to 12 nautical miles (22 km), where it has sovereignty; Kastellorizo's entitlement here is not disputed.
- Continental shelf: the seabed and subsoil that are the natural prolongation of a state's land territory, up to 200 nautical miles or more.
- EEZ: a zone up to 200 nautical miles in which a coastal state has sovereign rights over living and non-living resources. It is a creation of UNCLOS, a treaty to which Türkiye is not a party.
- Island effect: the weight an island is given when drawing a boundary line; full, partial, enclave or zero.
- Proportionality: a test of whether the resulting division of sea is reasonably related to the lengths of the relevant coasts.
- Blue Homeland (Mavi Vatan): the Turkish doctrine for Türkiye's maritime jurisdiction areas in the Black Sea, Aegean and Mediterranean. See also Crossroads Review's explainer.
Related guides on this site: The Eastern Mediterranean Side by Side, Cyprus Seen from Five Capitals, About States in Perspective and the home page.
States in Perspective presents global affairs with a dedicated perspective from Türkiye. Sections marked 'Türkiye's Position' reflect official Turkish policy as stated by Turkish government sources. Claims are attributed to primary sources such as treaties, UN documents and official statements.
Frequently asked questions
Does Kastellorizo have a continental shelf and EEZ?
Kastellorizo clearly has a territorial sea. Greece argues that under UNCLOS Article 121(2) it also has a continental shelf and EEZ, whereas Türkiye argues that its position next to a much longer mainland coast means these cannot cut off the mainland's projection. No court has ruled on the question, so it remains a matter of delimitation between the states concerned.
What does UNCLOS Article 121 say about islands?
Article 121 defines an island as a naturally formed area of land above water at high tide and says it generates the same zones as other land territory. Article 121(3) denies an EEZ and continental shelf to rocks that cannot sustain human habitation or economic life. It determines entitlement but not how overlapping entitlements are divided, which is a separate delimitation question.
Why does Türkiye say UNCLOS does not decide the matter?
Türkiye is not a party to UNCLOS and has consistently objected to its terms being applied against it. It relies on customary law and the principle of equity, citing cases such as the 1969 North Sea judgments. Ankara accepts that the ICJ has described the island regime of Article 121 as customary, but argues it governs entitlement, not an automatic full-effect outcome in delimitation.
Have international courts given islands full effect?
It depends on the case. Courts have often reduced or denied effect to small islands near larger coasts, as with the Channel Islands, Serpent Island and St Martin's Island. Islands that are large, populous or not distorting the outcome have sometimes received greater effect, so there is no single rule.
How do the Seville Map, the Libya MoU and the 2025 IOC-UNESCO plan relate to Kastellorizo?
The Seville Map, which Ankara rejects, gives Kastellorizo full effect and confines Türkiye to a narrow strip in the Gulf of Antalya. The 2019 Türkiye–Libya MoU and Türkiye's 2025 marine spatial planning, registered with IOC-UNESCO on 12 June 2025, are Ankara's documentary counterweights. Greece and the EU contest them, so the island question underlies all of these disputes.
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