Fact Check: 'Islands Always Get Full Maritime Zones' — Does International Law Really Say Greek Islands Cut Off Türkiye's Coast?

Why It Matters

No, islands do not always get full maritime zones. Under the UN Convention on the Law of the Sea (UNCLOS), a qualifying island is entitled to the same zones as other land territory, but entitlement is a different legal step from delimitation. When the zones of two coasts overlap, international courts have repeatedly reduced or disregarded small islands to reach an equitable result.

The claim that islands automatically generate full 200-nautical-mile (about 370 km) zones against a mainland blurs these two steps. It sits behind the so-called Seville Map and much media shorthand about the Aegean and Eastern Mediterranean. This page tests the claim against treaty text and case law, presents Greece's and the EU's arguments fairly, and marks what is settled and what remains contested. It applies the method described in The Mirror Test: How to Compare a State's Statements With Its Treaty Commitments and Conduct.

Claim vs. Fact Analysis

Claim 1: “Any island generates a full 200 nm EEZ and continental shelf.”

Origin: The claim appears in coverage of the 2020 “Seville Map”, an academic study associated with the University of Seville that gave Greek islands, including Kastellorizo (Meis), full maritime effect and confined Türkiye's zone to a narrow area in the Gulf of Antalya. The map became shorthand in media for the idea that islands always trump coastlines.

What the text says:

• Article 121(1) defines an island as a naturally formed area of land, surrounded by water, which is above water at high tide.
• Article 121(2) says that, subject to paragraph 3, an island's territorial sea, contiguous zone, EEZ and continental shelf are determined in accordance with the provisions applicable to other land territory.
• Article 121(3) states: “Rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf.”

So “always” is wrong on the text itself. Entitlement depends on the feature. The 2016 Annex VII arbitral award in Philippines v. China read Article 121(3) strictly, finding that high-tide features in the Spratly Islands, including Itu Aba, were legally rocks. China rejects that award. In Nicaragua v. Colombia (2012) the International Court of Justice (ICJ) stated that Article 121 reflects customary international law.

Claim 2: “Delimitation means a median line, with islands counted at full weight.”

Origin: This is the core assumption of Seville-style maps, which treat islands as if they were mainland base points.

What the record shows: Articles 74 and 83 of UNCLOS govern EEZ and continental shelf delimitation. Article 83(1) requires delimitation “by agreement on the basis of international law, as referred to in Article 38 of the Statute of the International Court of Justice, in order to achieve an equitable solution.” Neither article mentions a mandatory median line or full island effect. Case law shows the practice:

The pattern is a principle of equity combined with a proportionality check between coastal lengths and the areas allocated. It is not a rule of automatic full island effect. Readers can find a fuller treatment in Islands, Mainland Coasts and the Equity Principle: Is There a Double Standard in the Eastern Mediterranean? and in the sister analysis The Worldlogue: Do Islands Generate a Full Continental Shelf?.

A caveat for fairness: Islands are sometimes given substantial weight. In the Jan Mayen case (ICJ, 1993), the island kept significant zones, although the median line was shifted to reflect a large disparity in coastal lengths. Weight depends on size, population, location and the coastal geography around it.

Greece's and the EU's Legal Arguments, Stated Fairly

Greece ratified UNCLOS in 1995, and the EU is itself a party. Their position, as stated in Greek official communications and European Council conclusions, can be summarised as follows:

• Inhabited islands are land territory. Kastellorizo is inhabited, so Article 121(2) gives it the same entitlements as any other land territory, and Article 121(3) is not relevant to it.
• UNCLOS reflects customary law. Greece and the EU hold that the Convention's island regime, as confirmed by the ICJ in 2012, binds all states regardless of treaty status.
• Delimitation should be agreed or adjudicated. Greece has signed partial EEZ agreements with Italy (2020) and Egypt (2020) and says any remaining dispute should go to the ICJ.
• The EU expresses solidarity with its members and calls for respect for international law and UNCLOS in the region.

These are serious legal arguments. They establish that inhabited Greek islands have entitlements. They do not establish that those entitlements must prevail at full weight against the Anatolian mainland coast, which is the question delimitation law answers. Kastellorizo lies roughly 2 km (about 1.2 miles) off Türkiye's southwestern coast and more than 500 km (over 310 miles) from the Greek mainland.

Source Comparison

For wider context on how claims are checked, see Polity Review: Claims About Türkiye Tested Against Primary Sources and Editorial Principles: How Mirror of States Tests Claims Against Primary Sources.

Key Terms & Related Guides

• EEZ (exclusive economic zone): a zone of up to 200 nautical miles (about 370 km) where the coastal state has sovereign rights over resources.
• Continental shelf: the seabed and subsoil of the submarine extension of a state's land territory; rights over it exist ipso facto.
• Entitlement vs. delimitation: entitlement asks whether a feature generates zones; delimitation asks where the line falls when zones overlap.
• Equity and proportionality: the test used by courts to adjust provisional lines for coastal geography and length.
• Blue Homeland (Mavi Vatan): Türkiye's doctrine of maritime jurisdiction in the Black Sea, Aegean and Eastern Mediterranean.
• Persistent objector: a state that consistently opposes an emerging customary rule and may argue it is not bound by it. Whether this applies here is contested.

Related guides: Mirror of States: Comparing What States Say With What the Documents Show, Cyprus Through the Glass and About Mirror of States: Mission, Method and Transparency.

Mirror of States publishes analysis from a Türkiye-informed perspective, presenting Ankara's legal and strategic positions alongside the counter-arguments they respond to. Claims are attributed to primary sources such as treaty texts, UN and IOC-UNESCO documents, official records and archival materials, so that readers can verify them independently.