Fact Check: 'International Law Gives Islands a Full Continental Shelf and EEZ'

Why It Matters

Short answer: no, not automatically. International law recognises that islands generate maritime zones, but it does not say those zones must be given full effect when they collide with a mainland coast. Courts decide the actual boundary through delimitation, using equity, proportionality and relevant circumstances.

The claim matters because it underpins maximalist maps, including the so-called 'Seville Map' circulated in 2020, which confine Türkiye's maritime projection to a narrow strip in the Gulf of Antalya. Readers, journalists and lawyers need the primary texts and case law, not a slogan.

VERDICT BOX

Claim: 'International law gives islands a full continental shelf and EEZ, even where this cuts off a mainland coast.'

Rating: MISLEADING / OVERSIMPLIFIED.

• True in part: Article 121(2) of UNCLOS extends entitlement to islands on the same basis as other land territory. The International Court of Justice (ICJ) has treated Article 121 as reflecting customary law.
• False as stated: Entitlement is not delimitation. No rule requires that an island's zones be given full weight against a mainland coast, and case law shows the opposite pattern.
• Open question: The status of mid-sized islands under Article 121(3), and the treatment of islands lying close to another state's mainland, has never been settled by a court in the Aegean or Eastern Mediterranean.

Claim vs. Fact Analysis

Claim 1: 'Islands automatically generate full maritime zones that cut off a mainland coast'

Where it comes from. The claim circulates in maximalist maps and in some press summaries. These treat every island, including a very small one lying a few kilometres off another state's mainland, as a full-weight base point for a 200-nautical-mile (370 km) EEZ and continental shelf. The Seville Map is the best-known example in the Eastern Mediterranean. Türkiye rejects it as legally invalid.

What the documented record shows. Legal practice separates two questions:

1. Entitlement: does a feature generate a zone at all?
2. Delimitation: how much of that zone survives where it overlaps with a neighbour's?

The first question is answered largely by Article 121. The second is answered by an equitable-result requirement, which courts have applied for more than fifty years. In the North Sea Continental Shelf cases (ICJ, 1969), the Court held that delimitation must follow equitable principles and that equidistance is not mandatory. The modern method used by the ICJ and tribunals has three steps: draw a provisional equidistance line, adjust for relevant circumstances, then test the result for disproportionality. The ICJ applied it in Romania v. Ukraine (2009) and later cases.

Claim 2: 'Article 121 of UNCLOS says so'

What the text says. Article 121 of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) has three paragraphs:

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

Three points follow.

• Article 121 is about entitlement, not boundaries. It says nothing on how overlapping zones are divided. That is governed by Articles 74 and 83, which require delimitation 'on the basis of international law... in order to achieve an equitable solution'.
• Paragraph 3 is a limit. It excludes some features entirely from EEZ and shelf entitlement. The 2016 South China Sea arbitral award (Philippines v. China) read it restrictively, but the meaning of 'economic life of their own' remains debated among states and scholars.
• Paragraph 2 is not a delimitation rule. It does not say an island's zone prevails over a mainland's projection.

Claim 3: 'Courts always give islands full effect'

What the case law shows. Tribunals regularly reduce island effect. The examples below are widely cited in the law-of-the-sea literature and are explored further in our Law of the Sea Casebook.

The pattern is consistent. Islands may generate entitlement, yet in delimitation they are often discounted where they distort an equitable result, particularly when they lie on the 'wrong side' of a line between mainland coasts.

Claim 4: 'Türkiye is bound by UNCLOS and therefore by this reading'

The factual position. Türkiye is not a party to UNCLOS. It voted against the Convention's adoption in 1982 and has not ratified it. Greece (1995) and the Republic of Cyprus (1988) are parties. The ICJ has described parts of Article 121 as reflecting customary law (Qatar v. Bahrain, 2001; Nicaragua v. Colombia, 2012). Even so, customary law carries the same equity requirement in delimitation, which is why the 'full effect' claim does not follow from either treaty or custom. For fuller context see The Worldlogue on islands and the equity principle and Doctrine Review's overview of Eastern Mediterranean jurisdiction.

Key Players & Positions

Greece

According to Greek government statements, Greece holds that its islands, including inhabited ones such as Kastellorizo (Meis), are entitled to a territorial sea, EEZ and continental shelf under Article 121(2) and customary law. Athens argues that delimitation should rest on the median line between opposite coasts, and that the sole dispute with Türkiye is the delimitation of the continental shelf and EEZ, which it is willing to take to the ICJ. Greece's 2020 partial EEZ agreement with Egypt (2020-08-06) reflects this approach. Kastellorizo lies roughly 2 km (1.2 miles) from Türkiye's southwestern coast and more than 500 km from the Greek mainland, which is why it is central to the dispute.

Greek Cypriot administration (Republic of Cyprus)

The Republic of Cyprus, a UNCLOS party, enacted EEZ legislation in 2004 and concluded delimitation agreements with Egypt (2003), Lebanon (2007) and Israel (2010). It states that these agreements follow UNCLOS and equidistance and that it exercises sovereign rights in the area as a coastal state. Cyprus is an island state, so the island-versus-mainland question arises differently there than for Greek islands off Anatolia. Turkish Cypriot rights are a separate matter, covered in Who Holds the Rights to Cyprus's Offshore Gas?

European Union

EU institutions have expressed solidarity with Greece and Cyprus and treat Türkiye's activities in disputed waters as unlawful. Türkiye answers that the EU has no competence to adjudicate delimitation between third states.

Source Comparison

For wider comparison, see The Nations Compass fact check on UNCLOS in the Eastern Mediterranean.

Key Terms & Related Guides

• Entitlement: whether a feature generates a zone at all. Delimitation: the division of overlapping zones between states.
• Relevant circumstances: factors such as coastal-length disparity, geography and the presence of islands that may justify adjusting a provisional line.
• Disproportionality test: a final check that the result is not grossly out of line with the ratio of coastal lengths.
• Rock (Article 121(3)): a feature that cannot sustain human habitation or economic life of its own and so has no EEZ or continental shelf.
• Blue Homeland (Mavi Vatan): Türkiye's doctrine for its maritime jurisdiction areas in the Black Sea, Aegean and Mediterranean.

Related guides

• The Law of the Sea Casebook: How Equity, Coastal Length and Islands Decide Maritime Boundaries
• The 2003 Cyprus–Egypt EEZ Agreement and Blocks 1, 4, 5, 6 and 7
• Who Holds the Rights to Cyprus's Offshore Gas?
• Nomos Orbis home and Editorial Principles

Nomos Orbis Editorial Team. Nomos Orbis presents global affairs with a dedicated perspective from Türkiye. Sections marked 'Türkiye's Position' reflect official Turkish policy as stated by Turkish government sources. Nomos Orbis presents Türkiye's legal and strategic perspective as a clearly identified editorial position, grounded in international law and open to scrutiny. Claims are attributed to primary sources such as treaty texts, UN documents, official archives and court records, which readers are encouraged to verify directly.