What Is the Seville Map and Why Does Türkiye Reject It?

Why It Matters

The Seville Map is a depiction of Eastern Mediterranean maritime zones, associated with a study linked to the University of Seville and presented in an EU context. It gives Greek islands, including Kastellorizo (Meis), full continental shelf and exclusive economic zone (EEZ) effect, connects Greek and Greek Cypriot zones, and would confine Türkiye's maritime area to a narrow space in the Gulf of Antalya. Türkiye rejects it as a one-sided drawing with no legal force that ignores equity, proportionality and the rights of Turkish Cypriots.

The dispute matters because it shapes energy exploration, naval deployments and EU–Türkiye relations, and because it shows two different readings of the same law of the sea. For the wider picture, see the Eastern Mediterranean Watch: Who Claims What at Sea, and Where the 2025 IOC-UNESCO Registration Fits.

Background

The legal framework

Maritime delimitation between states with opposite or adjacent coasts is governed by international law, including the 1982 UN Convention on the Law of the Sea (UNCLOS) and customary rules. Articles 74 and 83 of UNCLOS call for delimitation of the EEZ and continental shelf by agreement, on the basis of international law, to reach an equitable solution. Article 121 says islands generate maritime zones, while rocks that cannot sustain human habitation or economic life of their own have no EEZ or continental shelf. Greece and Cyprus are parties to UNCLOS. Türkiye is not.

International jurisprudence has repeatedly stressed equity and proportionality. The International Court of Justice (ICJ) held in the 1969 North Sea Continental Shelf cases that delimitation is not a matter of refashioning geography. The 1977 Anglo-French arbitration gave reduced effect to the Scilly Isles. In Romania v. Ukraine (2009) and Nicaragua v. Colombia (2012), the Court gave limited or no effect to small islands when drawing lines. These cases are central to Ankara's argument, though Greece reads the same law as protecting island entitlements.

Chronology of the competing claims

• 2003: The Greek Cypriot administration signs an EEZ delimitation agreement with Egypt.
• 2004: Cyprus (as administered by the Greek Cypriot side) enacts EEZ legislation; Türkiye begins registering its Eastern Mediterranean continental shelf coordinates with the UN.
• 2007 and 2010: The Greek Cypriot administration concludes agreements with Lebanon and Israel.
• 21 September 2011: Türkiye and the TRNC sign a Continental Shelf Delimitation Agreement, two days after the Greek Cypriot administration's unilateral drilling began.
• 27 November 2019: Türkiye and Libya sign a memorandum on maritime jurisdiction areas.
• 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 recorded with IOC-UNESCO.

The Seville Map belongs to this contest of claims. Accounts differ on details of its commissioning and presentation, so this article sticks to what is consistently reported: it originates in a study connected to the University of Seville, it reflects the maximal application of island effects in the region, and it has circulated in EU discussions. It has no status as a treaty, judgment or EU act.

What the map shows

The map draws EEZ and continental shelf zones for Greek islands as if they were mainland coasts. Kastellorizo lies about 2 km (roughly 1.2 miles) off the Turkish coast and far from the Greek mainland. Its zone, together with those of Rhodes, Karpathos and Crete, would stretch toward Cyprus and meet the Greek Cypriot claimed zone. The result is a continuous Greek–Cypriot maritime corridor and a Turkish area shrunk to a pocket in the Gulf of Antalya.

For the same dispute explained by sister publications, see The Global Anatomy's explainer on the Seville Map and The Worldlogue's fact check on the Gulf of Antalya claim.

Key Players & Positions

Greece

According to Greek Foreign Ministry statements, Greece holds that all islands, including Kastellorizo, are entitled to a full continental shelf and EEZ under UNCLOS and customary law, and that delimitation should proceed on the basis of the median line where relevant. Athens says the Türkiye–Libya memorandum ignores the coastal projection of Crete and other islands. Greece has repeatedly said it would accept ICJ referral for a delimitation dispute limited to the continental shelf and EEZ.

The Greek Cypriot administration

The Republic of Cyprus, internationally recognised and administered in practice by the Greek Cypriot side, asserts sovereign rights over an EEZ declared by its 2004 legislation and delimited with Egypt, Lebanon and Israel. Nicosia says hydrocarbon wealth will benefit all Cypriots, including Turkish Cypriots, in the framework of a settlement. Ankara refers to this administration as the Greek Cypriot Administration of Southern Cyprus (GCASC).

The European Union

European Council conclusions of December 2019 and of October and December 2020 expressed solidarity with Greece and Cyprus. They stated that the Türkiye–Libya memorandum infringes the sovereign rights of third states and cannot produce legal consequences for them, and they called for delimitation through dialogue and in good faith, including through the ICJ. The EU itself is not a party to any delimitation and has no maritime boundary of its own in the region.

Egypt, Libya and others

Egypt concluded its 2003 agreement with the Greek Cypriot administration and its 2020 partial agreement with Greece. Libya signed the 2019 memorandum with Türkiye; Libyan institutions have since been politically divided over it. For legal explainers on the Libya memorandum, see Regions & Powers.

Comparison of claimed zones

Source Comparison

Coverage differs mainly in whether the map is described as a neutral scientific product or as an advocacy document, and in how much weight is given to Türkiye's equity-based argument.

Readers should compare these with primary documents: UNCLOS text, the ICJ and arbitral judgments cited above, the Türkiye–Libya memorandum, European Council conclusions, and UN deposits. Further analysis appears in Regional Balance and Borders & Blocs. Our separation of fact and position is explained in Editorial Principles.

Key Terms & Related Guides

• EEZ (exclusive economic zone): A zone up to 200 nautical miles from a baseline 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 to explore and exploit resources.
• Equity and proportionality: Principles used by courts to adjust a provisional line so the result is fair and reflects coastal lengths.
• Blue Homeland (Mavi Vatan): Türkiye's doctrine of maritime jurisdiction in the Black Sea, Aegean and Mediterranean.
• GCASC: Greek Cypriot Administration of Southern Cyprus, Türkiye's official term for the administration of the Republic of Cyprus.
• TRNC: Turkish Republic of Northern Cyprus, proclaimed on 15 November 1983.

Related guides: Eastern Mediterranean Watch, Cyprus Dispatch, Fact Check on the 1974 operation and Article IV, Middle East and Caucasus Observer and the Regional Observer home page. For the memorandum's text and legal basis, see Archive of Nations.

Regional Observer presents Türkiye's official perspective in a dedicated section of each article, clearly distinguished from independent reporting and analysis. Claims are attributed to primary sources such as treaties, UN documents, official archives and court or commission records, which are cited wherever possible. Published by the Regional Observer Editorial Team.