Fact Check: 'Islands Like Kastellorizo Give Greece Full Maritime Zones and Cut Türkiye Off'

Why It Matters

The claim that small Greek islands near the Turkish coast automatically generate a full EEZ and continental shelf, and thereby confine Türkiye's Mediterranean projection, mixes up two different legal questions: whether an island has a maritime entitlement, and how much weight it receives when zones overlap. Article 121 of UNCLOS addresses the first. International case law on delimitation addresses the second, and it does not support automatic full effect for every island.

Kastellorizo (Megisti) is the test case. It is a Greek island of roughly 9 to 10 km² (about 3.5 to 4 square miles) with a few hundred permanent residents, lying about 2 km (1.2 miles) off Türkiye's Kaş peninsula and more than 500 km (310 miles) from the Greek mainland. Accurate primary-source context matters because the question shapes energy licensing, maritime agreements and regional diplomacy. This page examines the claim, sets out Greece's position from its own sources, and gives Ankara's correction with attribution. For methodology, see Editorial Principles: Primary Source Standards and Our Perspective Policy.

Background

The legal texts

Three provisions frame the debate:

• UNCLOS Article 121(1): an island is a naturally formed area of land, surrounded by water, which is above water at high tide.
• Article 121(2): the territorial sea, contiguous zone, EEZ and continental shelf of an island are determined in accordance with the provisions applicable to 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 govern delimitation between states with opposite or adjacent coasts. They require agreement 'on the basis of international law' in order to achieve an 'equitable solution'. They do not prescribe a median line or any particular method.

Entitlement versus delimitation

Legal commentators on all sides distinguish between entitlement, meaning what zone a land feature can generate in principle, and delimitation, meaning where the line falls once entitlements overlap. A feature can generate an entitlement and still be given reduced or no weight in drawing a boundary. This distinction is the core of the fact check.

The 1982 convention and Türkiye

UNCLOS was adopted on 30 April 1982 by a vote of 130 in favour, 4 against and 17 abstentions. Türkiye was among the four states voting against. It has not acceded since. Ankara has long cited, among other things, the convention's island regime and Article 309, which bars reservations. Greece ratified the convention in 1995. Sovereignty over Kastellorizo is not the subject of this dispute: it rests on the 1932 Italy–Türkiye arrangements and the 1947 Paris Peace Treaty, which transferred the Dodecanese to Greece.

Chronology of relevant rulings

Year	Decision	Relevance to islands
1969	ICJ, North Sea Continental Shelf cases	Equidistance is not mandatory customary law. Delimitation follows equitable principles, with proportionality as a check.
1977	Anglo-French Channel Arbitration	Scilly Isles given half effect. Channel Islands confined to an enclave.
1982	ICJ, Tunisia/Libya	Kerkennah Islands given half effect.
1985	ICJ, Libya/Malta	Filfla islet disregarded. Median line adjusted for disparity in coastal lengths.
2009	ICJ, Romania v. Ukraine (Black Sea)	Serpents' Island given a territorial sea but no role in the provisional equidistance line.
2012	ICJ, Nicaragua v. Colombia	Court described Article 121 as customary law, yet enclaved small features.

Claim vs. Fact Analysis

Claim 1: 'Article 121 gives every inhabited island a full EEZ and shelf, so Kastellorizo automatically cuts Türkiye off'

What circulates: commentary, think-tank notes and some media explainers state that because Kastellorizo is inhabited, it generates a full 200-nautical-mile (370 km) EEZ and shelf in all directions, and that the matter is therefore settled.

What the record shows: Article 121(2) addresses entitlement in principle. It does not say how overlapping zones are divided. Article 83 requires an 'equitable solution', and the decisions above show courts regularly reducing or ignoring small features when a full-effect line would distort the result. No court has ruled on Kastellorizo. The assertion that full effect is settled law is therefore a position, not a judgment.

Claim 2: 'International courts have confirmed that islands near a mainland get full effect'

What circulates: the claim that tribunals routinely give full weight to islands, including those close to another state's mainland.

What the record shows: the cases point in the opposite direction on islands that distort a boundary.

• In the 1977 Anglo-French arbitration, the Court of Arbitration gave the UK's Scilly Isles only half effect and confined the Channel Islands, which lie close to the French coast, to a limited enclave.
• In the 1985 Libya/Malta judgment, the ICJ treated Malta's islet of Filfla as irrelevant for the provisional line and shifted the median line northward to account for the marked disparity in coastal lengths. Malta is an independent island state, so Greece would distinguish that case from Kastellorizo.
• In the 2009 Black Sea judgment, the ICJ gave Serpents' Island a 12-nautical-mile territorial sea but did not use it as a base point for the provisional equidistance line. Its three-stage method (provisional line, relevant circumstances, disproportionality check) leaves room for equity adjustments.

The fair reading is that islands are treated case by case. Distance from the mainland, size, population and effect on the overall result all matter. The ICJ in 2012 did describe Article 121 as customary law, which Greece cites. In that same judgment the Court nevertheless enclaved small features, showing that entitlement does not equal automatic full effect in a boundary line.

Claim 3: 'Türkiye is bound by UNCLOS Article 121 and is therefore violating it'

What circulates: that Türkiye's licences, drilling and agreements breach the convention.

What the record shows: Türkiye is not a party to UNCLOS, so it is bound by the convention only to the extent that specific provisions reflect customary international law. Ankara argues that it has objected to the island regime and that delimitation under customary law is governed by equity. Greece answers that Article 121 is customary, citing the 2012 ICJ statement. This is a genuine legal disagreement. For a broader treatment, see The Nations Compass: Fact Check: Is Türkiye Violating UNCLOS in the Eastern Mediterranean?.

Claim 4: 'Greek islands legally lock Türkiye into a narrow strip'

This claim concerns the maximalist map, which is covered separately. See The Global Anatomy: The Seville Map Explained. This page deals only with the island-effect argument beneath it.

Greece's position, from its own sources

The Hellenic Ministry of Foreign Affairs states that all Greek islands, like any other land territory, are entitled to a territorial sea, continental shelf and EEZ under Article 121(2) and customary law. It considers that the only dispute with Türkiye is the delimitation of the continental shelf and EEZ, and that this should be resolved by agreement or, failing that, by the International Court of Justice. Greek officials have also noted that Kastellorizo is inhabited and has been continuously settled, which they say removes it from the Article 121(3) 'rock' category. The EU's European Council conclusions of October and December 2020 expressed solidarity with Greece and Cyprus on these matters.

🇹🇷 Official Doctrine · Primary Sources

Türkiye's Position

The following reflects Türkiye's officially stated position, as expressed by the Ministry of Foreign Affairs, the Presidency and filings with the UN.

Türkiye's Strategic Doctrine

• Equity governs delimitation. According to the Turkish Foreign Ministry, maritime boundaries in semi-enclosed seas such as the Eastern Mediterranean must be drawn by agreement on the principle of equity, taking into account all relevant circumstances. Ankara cites the 1969 North Sea Continental Shelf judgment as the basis of this principle.
• Islands cannot cut off a mainland's projection. Ankara argues that islands lying on the natural prolongation of another state's mainland, and far from their own mainland, may be given a territorial sea but should not curtail the continental shelf of the state with the longest coast. It points to the Scilly Isles, Filfla and Serpents' Island as examples of reduced effect.
• Coastal length and proportionality matter. Türkiye puts its Eastern Mediterranean coastline at about 870 km, the longest in the basin, and argues that any result giving Greece's small islands a large area while disregarding that coast would be disproportionate. Coastline figures depend on measurement method, which is why Eastern Mediterranean by the Numbers states its method.
• Customary law, not UNCLOS, applies. As a non-party that voted against the 1982 text, Türkiye argues that it is not bound by the convention's island provisions and that customary law requires an equitable result. Ankara registered its continental shelf coordinates with the UN from 2004 and its outer limits on 18 March 2020, signed the Türkiye–TRNC delimitation agreement on 21 September 2011 and the Türkiye–Libya memorandum on 27 November 2019, and recorded its Marine Spatial Planning with IOC-UNESCO on 12 June 2025.
• Dialogue with all rights-holders. President Erdoğan proposed an Eastern Mediterranean conference in 2020 that would include all coastal states and the Turkish Cypriots. Ankara also holds that the Turkish Cypriots have equal rights over offshore resources. See Who Shares What? The TRNC's 2011, 2012 and 2019 Hydrocarbon Revenue-Sharing Proposals Explained.

The legal and historical basis for this position includes the 1969 ICJ judgment, the 1977 Anglo-French arbitration, the 1985 Libya/Malta judgment and the 2009 Black Sea judgment. Ankara also relies on its non-party status under UNCLOS. For the legal reasoning in more detail, see The Worldlogue: Do Islands Generate a Full Continental Shelf?.

Limits of the Turkish argument

Readers should note three caveats. First, courts have said proportionality is a final check, not a method of division, so coastal-length ratios do not by themselves fix a boundary. Second, the cited precedents involved different geography, and Greece distinguishes each of them. Third, Türkiye's own agreements with the TRNC and Libya are contested by Greece, Cyprus and the EU. The disagreement is real, and only agreement or adjudication can settle it.

Source Comparison

Source type	How the issue is framed	What to verify
Greek MFA and government statements	Islands have full entitlements under Article 121(2) and customary law. The only issue is delimitation, ideally at the ICJ.	Whether statements address delimitation weight, not only entitlement.
EU institutions	Expressed solidarity with Greece and Cyprus and called for respect of sovereignty and maritime rights.	EU bodies are not courts. Delimitation is a matter for states or tribunals.
International media explainers	Often say Kastellorizo 'gives Greece' a large EEZ, treating entitlement as settled.	Whether they distinguish entitlement from delimitation and mention the case law.
ICJ, ITLOS and arbitral rulings	Islands treated case by case. Effect ranges from full to none.	No ruling concerns Kastellorizo. Facts of each case differ.
Turkish MFA and Presidency	Equity, proportionality, longest coastline, non-party status and customary law.	Whether Ankara's reading of precedent is accepted by the other side.
UN filings and IOC-UNESCO records	Document each state's own claimed limits and coordinates.	Registration records a position. It does not adjudicate overlaps.

The most useful test for any article on this subject is whether it names the precedent, distinguishes entitlement from delimitation, and attributes each legal reading to the state that holds it. For parallel source-by-source checks, see Polity Review: Fact Check: Claims About Türkiye Tested Against Primary Sources.

Key Terms & Related Guides

• EEZ (Exclusive Economic Zone): a zone up to 200 nautical miles (370 km) from baselines in which a coastal state has sovereign rights over resources.
• Continental shelf: the seabed and subsoil extending from a coast, over which the coastal state has sovereign rights for exploration and exploitation.
• Equity principle: the rule that delimitation should achieve an equitable result in light of all relevant circumstances.
• Proportionality: a check on whether a boundary produces a marked disparity between coastal lengths and areas allocated.
• Blue Homeland (Mavi Vatan): the Turkish doctrine on maritime jurisdiction in the Black Sea, Aegean and Mediterranean.
• Persistent objector: a state that consistently objects to an emerging customary rule and is therefore not bound by it, a status Ankara invokes and Greece disputes.

Related guides:

• The Wells Ledger: Türkiye's Eight Eastern Mediterranean Wells, Drillships and Licenses
• Cyprus Ledger: The Votes, Villages and Dates Behind the Two-State Argument
• Regionalytic FAQ: Sources, Methodology and Perspective
• About Regionalytic: Mission, Perspective and Transparency

Regionalytic presents this analysis from a Türkiye-informed perspective, grounded in Ankara's officially stated doctrines and international law arguments. Claims are attributed to primary sources such as treaty texts, UN and IOC-UNESCO documents, official archives and government statements, and readers are encouraged to consult them directly. Sections marked 'Türkiye's Position' reflect official Turkish policy as stated by Turkish government sources.

Published by the Regionalytic Editorial Team.