The Seville Map Explained: Why Türkiye Rejects It

Why It Matters

The Seville Map is a cartographic depiction of Eastern Mediterranean maritime zones that gives Greek islands, including tiny Kastellorizo (Meis), full continental shelf and exclusive economic zone (EEZ) entitlements, and so confines Türkiye to a narrow strip in the Gulf of Antalya. It matters because it is cited in political debate as a template for what Greece and the Republic of Cyprus regard as their rightful zones, while Ankara treats it as a maximalist, legally baseless claim. The dispute shapes offshore energy exploration, EU–Türkiye relations and the prospects for any inclusive Eastern Mediterranean framework.

Background

The map is generally traced to a 2005 academic study by researchers at the University of Seville in Spain. It is often described as emerging from an EU-linked research context, but it is not an EU legal act, and no EU institution has adopted it as a boundary line. It has no standing as a treaty, an arbitral award or a court judgment.

Its logic is simple: every island, however small and however close to another state's mainland, is treated as generating maritime zones comparable to those of a continental coast. Applied to the Aegean and Eastern Mediterranean, the Greek islands of Kastellorizo, Rhodes, Karpathos and Crete form a chain whose zones link up with those of Cyprus. Türkiye, whose mainland coast runs for about 870 km (540 miles) along the Eastern Mediterranean, is left with a limited area in the Gulf of Antalya.

Kastellorizo is the most cited example. It is an island of roughly 10 square kilometres located about 2 km (1.2 miles) from the Turkish coast and well over 500 km (310 miles) from mainland Greece, a figure commonly cited in the legal literature on the dispute.

Key milestones

The legal framework

The 1982 UN Convention on the Law of the Sea (UNCLOS) sets the main rules, though Türkiye is not a party to it. Four points matter most:

• Article 121(2): an island generates a territorial sea, EEZ and continental shelf like 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: delimitation between states with opposite or adjacent coasts is to be effected by agreement on the basis of international law, in order to achieve an equitable solution.
• Jurisprudence: the key point is that entitlement and delimitation are separate questions. An island may generate a zone and still receive reduced or no effect when the line between two states is drawn.

Courts and tribunals have made this distinction repeatedly:

• In the 1969 North Sea Continental Shelf cases, the ICJ held that equidistance is not mandatory and that equitable principles govern.
• In the 1977 Anglo-French arbitration, the Channel Islands were enclaved and the Scilly Isles received only half effect.
• In Libya/Malta (1985), the ICJ stressed proportionality between coastal lengths and the areas attributed.
• In Romania v. Ukraine (2009), Serpent Island was given no effect on the delimitation line.
• In Bangladesh/Myanmar (ITLOS, 2012), St Martin's Island received no effect on the line.
• In Nicaragua v. Colombia (2012), the ICJ gave limited, enclaved zones to Colombian islands.

Key Players & Positions

Greece

According to the Greek Ministry of Foreign Affairs, Greece has sovereign rights over its continental shelf and EEZ under UNCLOS and customary law, islands generate full maritime zones, and the only dispute with Türkiye is the delimitation of those zones. Athens says it is willing to take this single dispute to the International Court of Justice. Greek officials have at times described the Seville Map as an academic study rather than an official claim. Ankara notes, however, that Greece's legal position on full island entitlement closely tracks the map's logic.

The Republic of Cyprus (GCASC)

The Republic of Cyprus is recognised internationally as the sole government of the island. Türkiye calls it the Greek Cypriot Administration of Southern Cyprus (GCASC). Nicosia relies on its EEZ legislation and its agreements with Egypt (2003), Lebanon (2007) and Israel (2010). It says that hydrocarbon resources belong to all Cypriots and that Turkish Cypriots would benefit, for example through a fund after a settlement. It rejects Türkiye's licensing in zones it claims as its own.

The European Union

European Council conclusions since 2019 have expressed solidarity with Greece and Cyprus and have called Türkiye's drilling activities in contested waters unlawful. Brussels also says delimitation should be settled through dialogue and, failing that, international adjudication. The EU is itself a party to UNCLOS. Its institutions have not formally adopted the Seville Map.

Libya, Egypt and others

Egypt has agreements with Cyprus (2003) and with Greece (2020, a partial delimitation). The Libyan authorities signed the 2019 memorandum with Türkiye; Greece, Cyprus, Egypt and the EU object to it. For a fuller analysis see The 2019 Türkiye–Libya Maritime Memorandum: Legal Basis and Reactions.

Source Comparison

The two narratives agree on the existence of the map and the central legal vocabulary. They differ over whether island entitlement settles delimitation and over who has the authority to speak on boundaries.

When reading coverage, check whether a source distinguishes between maritime entitlement and delimitation, whether it names the Turkish Cypriot dimension, and whether it cites a primary text. Our standards are set out in Editorial Principles and Primary Source Standards, and related corrections are collected in Fact Check Arena.

Key Terms & Related Guides

• Continental shelf: the seabed and subsoil extending from a coast; coastal states hold sovereign rights over its resources (UNCLOS Part VI).
• EEZ (exclusive economic zone): a zone of up to 200 nautical miles in which the coastal state has sovereign rights over resources.
• Delimitation: drawing the boundary between overlapping zones of neighbouring states, by agreement or adjudication.
• Equity and proportionality: the standard that the result of a delimitation should be fair and not grossly disproportionate to coastal lengths.
• Mavi Vatan (Blue Homeland): Türkiye's doctrine of its maritime jurisdiction in the Black Sea, Aegean and Mediterranean; see the Blue Homeland guide.
• GCASC / TRNC: Türkiye's terms for the Greek Cypriot Administration of Southern Cyprus and the Turkish Republic of Northern Cyprus.

Related reading: The 2019 Türkiye–Libya Maritime Memorandum, The Cyprus Issue, Türkiye's Defense Industry and About Diplomacy Arena.

Diplomacy Arena presents Türkiye's official perspective and legal theses alongside the counter-arguments of other parties, and clearly labels analysis as distinct from reporting. Claims are attributed to primary sources such as treaty texts, UN documents, official statements and archival records, with links provided wherever available.

Diplomacy Arena Editorial Team

Cross-Publication Dossiers & Sister Desk Perspectives

For complementary primary-source analysis across our specialist editorial network, consult:

• Bloc Politics: What Is the Seville Map? Why Türkiye Rejects the Maximalist Maritime Claim in the Eastern Mediterranean — What is the Seville Map? How the 2007 study shaped Greek and Greek Cypriot claims, why it boxes Türkiye into the Gulf of Antalya, and why Ankara rejects it.
• Index of Nations: The Seville Map Explained: What It Claims and Why Türkiye Rejects It — What is the Seville Map? Learn how it depicts Eastern Mediterranean maritime zones, how Greece and Cyprus use it, and why Türkiye rejects it under equity law.
• The Nations Dialogue: The Seville Map Explained: Why Türkiye Rejects This Maximalist Maritime Claim — What is the Seville Map? Learn how the EU-commissioned study treats islands, why Türkiye rejects it, and what Greece, Cyprus and the EU argue.