Fact Check: 'Islands Generate Full Maritime Zones, So Türkiye's Continental Shelf Claim Ignores Kastellorizo' — What Case Law and the Equity Principle Actually Say

Why It Matters

Do islands get a full continental shelf and EEZ? Under Article 121(2) of the 1982 UN Convention on the Law of the Sea (UNCLOS), islands generate the same entitlements as other land, but Articles 74 and 83 require delimitation between overlapping claims to reach an equitable solution. Courts have often given small islands reduced effect.

The claim circulates in Greek and Greek Cypriot official positions and in parts of European media. Because islands have the same entitlements as other land, the argument runs, Kastellorizo (Meis) projects a large maritime zone, and Türkiye's Eastern Mediterranean claims are therefore 'illegal'. This fact check tests that legal reasoning, not the political merits of either side.

Rating: Misleading / Incomplete. The first step (islands have entitlements) is correct. The conclusion (full effect that overrides a mainland coast) does not follow from the treaty text or from the case law. For how we attribute primary sources, see our Editorial Principles.

Claim vs. Fact Analysis

The claim examined here says that Kastellorizo (Meis), about 2 km (1.2 miles) off Anatolia, automatically projects a full 200-nautical-mile zone that cuts Türkiye off from the Eastern Mediterranean. UNCLOS Article 121 confirms entitlement, but no treaty rule or judgment guarantees full effect in overlapping-claims delimitation, and the case law points the other way.

The claim and where it comes from

Greece, a party to UNCLOS since 1995, holds that all its islands, Kastellorizo included, are entitled to a territorial sea, EEZ and continental shelf under Article 121(2). It also treats the Convention as reflecting customary law that binds non-parties. The Republic of Cyprus administration (the Greek Cypriot Administration of Southern Cyprus, GCASC) takes a similar line.

The European Council, in conclusions in December 2019 and during 2020, expressed solidarity with Greece and Cyprus. It described the Türkiye–Libya memorandum as incompatible with the law of the sea and without legal consequences for third states. On 6 August 2020 Egypt and Greece signed a partial EEZ delimitation agreement. The so-called 'Seville Map' reflects the same reading; see our Seville Map fact check for the EU-competence angle.

This position has real strengths. Kastellorizo is inhabited and its sovereignty is not at issue, so the 'rock' exclusion in Article 121(3) is not the main question. The dispute is about the weight the island receives, not about whether it exists in law.

Verification 1: What does Article 121 actually say?

Article 121 has three paragraphs:

• Paragraph 1: an island is a naturally formed area of land, surrounded by water, above water at high tide.
• Paragraph 2: subject to paragraph 3, an island's territorial sea, contiguous zone, EEZ and continental shelf are determined under the provisions applicable to other land territory.
• Paragraph 3: rocks that cannot sustain human habitation or economic life of their own have no EEZ or continental shelf.

Paragraph 2 settles entitlement. It does not say how an island's zone is drawn where it meets another state's zone. Mainland coasts also have to be delimited under the same provisions, so 'the same as other land' includes the same equitable limits.

Verification 2: Is entitlement the same as delimitation?

No. Entitlement is the right of a land feature to generate a zone. Delimitation is the drawing of a boundary where zones from opposite or adjacent coasts overlap.

Articles 74(1) (EEZ) and 83(1) (continental shelf) provide that delimitation between states with opposite or adjacent coasts shall be effected by agreement on the basis of international law, as referred to in Article 38 of the ICJ Statute, 'in order to achieve an equitable solution'. The Convention contains no rule of 'full effect' for islands. In Romania v. Ukraine (2009) the ICJ set out the method courts now generally follow: a provisional equidistance line, then adjustment for relevant circumstances, then a check for disproportion.

Verification 3: What does the case law show on whether islands get full effect?

The decisions below are the established reference points. None concerns Kastellorizo.

Case	What the court or tribunal did	Relevance for islands
North Sea Continental Shelf (ICJ, 1969)	Rejected equidistance as a mandatory customary rule; delimitation by agreement under equitable principles, taking relevant circumstances, natural prolongation and a reasonable degree of proportionality into account	Foundation of the equity approach; recognised that small coastal projections can distort a strict median line
Anglo-French Continental Shelf (Court of Arbitration, 1977)	Confined the UK's Channel Islands, which lie close to France, to a 12-nm enclave; gave the Scilly Isles reduced (half) effect	Islands close to another state's coast received limited weight
Libya/Malta (ICJ, 1985)	Drew a median line, then adjusted it because of the large disparity in coastal lengths; the uninhabited islet of Filfla was not counted in drawing the line	Proportionality and coastal length matter; tiny features can be disregarded
Romania v. Ukraine (ICJ, 2009)	Recognised a 12-nm territorial sea for Serpents' Island but did not use it as a base point; it had no effect on the continental shelf/EEZ line beyond that arc; the Court did not rule on whether it was an Article 121(3) rock	A Black Sea precedent: sovereignty over an island did not translate into delimitation weight
Nicaragua v. Colombia (ICJ, 2012)	Gave several small Colombian cays territorial-sea enclaves and adjusted the line so the Colombian islands received less than a full projection against Nicaragua's mainland coast	Disparity in coastal lengths and small size reduced effect
South China Sea Arbitration (PCA, 2016)	Interpreted Article 121(3): rock status depends on a feature's objective capacity, of its own, to sustain human habitation or economic life; found that no Spratly feature generated an EEZ; did not delimit any boundary	Clarifies the 'rock' threshold only; China rejects the award; it says nothing on weighting inhabited islands in overlaps

Two cautions keep this honest. First, Libya/Malta also held that within 200 nm the distance from the coast, not natural prolongation, is the basis of title, which weakens arguments built purely on natural prolongation. Second, these cases show that courts often reduce island weight, not that they always do. The outcome depends on the facts of each case.

The 1978 ICJ judgment on the Aegean Sea Continental Shelf is sometimes cited here, but the Court found it lacked jurisdiction and did not reach the merits; see Kosmonomos on what the 1978 judgment actually decided.

Verification 4: What is the cut-off effect and proportionality test for Kastellorizo (Meis)?

A cut-off effect occurs when a boundary line blocks a coast from projecting seaward as its geography would otherwise allow. Proportionality is the final check: is the maritime area allocated grossly out of line with the relevant coastal lengths?

Turkish official sources cite a mainland coast of roughly 870 km in the Eastern Mediterranean. Kastellorizo is an island of a few square kilometres, about 2 km from the Anatolian shore and, as is widely recognised, more than 500 km from the Greek mainland. Ankara argues that this combination is the kind of situation in which earlier tribunals limited island effect.

Greece answers that the relevant coast is not Kastellorizo alone but the chain of Greek islands including Rhodes, Karpathos and Crete, and that Greek sovereignty over the Dodecanese rests on the 1947 Paris Peace Treaty. Both points are legitimate. The 870 km figure is a national one, and a tribunal would define the 'relevant coast' and 'relevant area' itself, which is where the real contest lies. Sister analysis: Political Contours on whether an island can cut off a mainland's continental shelf.

Verdict: Misleading / Incomplete

• Accurate: Article 121(2) gives inhabited islands, including Kastellorizo, maritime entitlements.
• Misleading: treating entitlement as a guarantee of full effect, or treating a different Turkish reading as automatically 'illegal'.
• Incomplete: no court has fixed a rule for Kastellorizo, and the issue remains disputed. The finding concerns the specific legal claim, not the political merits.

🇹🇷 Official Policy · Primary Sources

Türkiye's Position

According to the Turkish Ministry of Foreign Affairs, maritime delimitation in the Eastern Mediterranean must be effected by agreement on the basis of international law and equity, and Ankara argues that islands near another state's mainland cannot cut off the projection of the longest mainland coastline in the region. Greece and the EU reject this reading.

• Equity and agreement first. The Turkish MFA states that delimitation must be achieved by agreement on the basis of international law and equity, taking all relevant circumstances into account. Ankara cites the ICJ's North Sea Continental Shelf (1969) and Libya/Malta (1985) judgments for this approach.
• Islands on the 'wrong side' of the median line. Ankara argues that an island lying close to another state's mainland cannot cut off that mainland's coastal projection, and that the case law supports giving such features limited effect. Turkish MFA statements on the Aegean and the Eastern Mediterranean apply this to Kastellorizo.
• Non-party and persistent objector. Türkiye voted against UNCLOS in 1982 and has not signed it. Ankara says it is a persistent objector to rules it considers inequitable, including the absence of any room for reservations (Article 309) and the treatment of islands in semi-enclosed seas. Greece replies that Article 121 is customary law binding on all states.
• Equal rights of Turkish Cypriots and open dialogue. Türkiye holds that Turkish Cypriots, as co-owners of the island, have equal inherent rights to offshore resources, as reflected in the Türkiye–TRNC continental shelf agreement of 21 September 2011. President Erdoğan's 2020 call for an Eastern Mediterranean Conference including all coastal states and Turkish Cypriots keeps the door open. See what is a guarantor power: Cyprus Treaty of Guarantee Article IV and our fact check on whether Turkish Cypriots are a minority in Cyprus.
• Registered positions. Türkiye filed the outer limits of its continental shelf with the UN on 18 March 2020 and signed the Türkiye–Libya maritime memorandum on 27 November 2019. It unveiled its Marine Spatial Planning on 16 April 2025 and registered it with IOC-UNESCO on 12 June 2025.

On the last point, precision matters. The Türkiye marine spatial planning IOC-UNESCO registration 2025 records Türkiye's planning of its maritime areas with a UN body. It is not a boundary ruling, it does not bind Greece or any other state, and IOC-UNESCO does not adjudicate delimitation. Likewise, the 2020 UN filing records Türkiye's claimed limits and creates no boundary by itself.

Greece rejects Ankara's reading and presents the EU's solidarity position. Greece, Egypt and Cyprus object to the 2019 memorandum, and Libyan domestic politics also surround it. See Index of Nations on the 2019 memorandum.

Source Comparison

International headlines often frame the Kastellorizo dispute as 'Turkish claims versus Greek islands', while the UNCLOS text, ICJ and arbitral judgments, Turkish Foreign Ministry notes and UN registrations describe a delimitation dispute over weight, proportion and equity. The table below compares the two registers claim by claim without quoting any outlet.

Common framing	What the primary record says	Assessment
'Turkey challenges Greek islands'	The Kastellorizo question concerns the extent of maritime zones, not a claim to the island itself	Conflates sovereignty with delimitation
'Islands automatically get a full 200-nm EEZ'	Article 121(2) gives entitlement; Articles 74(1) and 83(1) require an equitable solution; no 'full effect' rule exists	Incomplete
'International law is settled in Greece's favour'	ICJ and arbitral practice (1977, 1985, 2009, 2012) often reduces or removes island effect; none concerns Kastellorizo	Overstated
'Türkiye has no standing because it is not an UNCLOS party'	Delimitation is also governed by customary law applied by the ICJ; Ankara cites 1969 and 1985 judgments; Greece says Article 121 is customary	Contested on both sides
'Turkish UN and UNESCO filings are boundaries'	The 2020 filing and the 12 June 2025 IOC-UNESCO registration record positions; neither is an adjudication	Overstated by both critics and supporters
'The legal question has been answered'	No court or tribunal has delimited around Kastellorizo	Open question

Some coverage treats the EU's solidarity conclusions as legal findings. They are political statements by the European Council. See Global Affairs Monitor on the Seville Map. Reporting that treats Ankara's registrations as final boundaries makes the reverse error. In both cases the useful test is the same: what does the treaty text or judgment actually say?

Key Terms & Related Guides

Seven terms drive this debate: entitlement, delimitation, relevant coast, cut-off effect, proportionality, enclave and persistent objector. Each has an established meaning in international law and is summarised below, with links to related Politics of Nations guides and sister-publication analyses.

• Entitlement: a land feature's right to generate maritime zones (Article 121).
• Delimitation: the drawing of a boundary between overlapping zones (Articles 74, 83).
• Relevant coast / relevant area: the coastlines and sea area a court counts when testing proportionality.
• Cut-off effect and proportionality: the blocking of a coast's projection, and the test of whether the result is grossly disproportionate.
• Enclave: a limited zone around an island, as in the Channel Islands in 1977.
• Persistent objector: a state that has consistently opposed a rule in its formation. Whether a rule binds it is itself contested here.

Related reading: how do countries define national interest foreign policy doctrine; the Seville Map fact check; and the Türkiye marine spatial planning IOC-UNESCO registration 2025 guide.

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Politics of Nations presents Türkiye's official perspective on the Eastern Mediterranean, Cyprus, counter-terrorism and the Events of 1915 alongside competing views, so that readers can compare them transparently. Claims are attributed to primary sources such as treaties, UN documents, the Ottoman and Turkish archives, and official statements. Sections marked 'Türkiye's Position' reflect official Turkish policy as stated by Turkish government sources.

Politics of Nations Editorial Team