Fact Check: Does the 'Seville Map' Define the EU's Maritime Border With Türkiye?

Why It Matters

No, the 'Seville Map' does not define the EU's maritime border with Türkiye. It is a map from an academic study, widely circulated in Greek, Greek Cypriot and some European policy debates, and it has never been adopted as a treaty, a judgment of an international court or an arbitral award. Under international law, only agreement between the coastal states concerned, or adjudication, can fix a maritime boundary.

The claim matters because the map is often presented in headlines and policy papers as if it were the legal baseline of the Eastern Mediterranean. It shows Türkiye confined to a narrow strip of sea in the Gulf of Antalya. If readers accept it as an authoritative boundary, they will misjudge both the legal dispute and the negotiating options. This fact check separates what the map is, what the law requires and what each party actually argues. For our sourcing standards, see our Editorial Principles.

Claim vs. Fact Analysis

The claim and its origin

The claim: 'The Seville Map, produced in a study for the EU, shows the legitimate maritime zones of Greece and the Republic of Cyprus in the Eastern Mediterranean, and confines Türkiye to a narrow strip of sea in the Gulf of Antalya.'

Origin: The map is associated with a study by academics connected to the University of Seville. It applies a maximalist approach in which islands such as Kastellorizo (Meis) generate full maritime zones, which compresses the zones of Türkiye's mainland coast. It has been reproduced in media and political commentary, often with the label 'EU map', which implies an official status. Sister publication The Worldlogue examines the same claim in Fact Check: Does the 'Seville Map' Confine Türkiye to the Gulf of Antalya?.

Claim 1: 'The Seville Map is a legal boundary'

Record: It is not. A legally binding maritime boundary exists only in these forms:

• a bilateral or multilateral delimitation treaty ratified by the states concerned;
• a judgment of the International Court of Justice (ICJ), or an award of an arbitral tribunal, accepted by the parties;
• in some cases, a binding decision by a tribunal such as ITLOS, where the parties have consented to its jurisdiction.

The Seville Map is none of these. It records no consent by Türkiye, and, as a study product, it creates no obligations for any state. Calling it a 'border' confuses a scholarly or advocacy illustration with a legal instrument.

Claim 2: 'UNCLOS and the law of the sea settle the matter in favour of the map'

Record: The text of UNCLOS is less decisive than the claim suggests.

• Articles 74 and 83 say that delimitation of the exclusive economic zone (EEZ) and continental shelf between states with opposite or adjacent coasts 'shall be effected by agreement on the basis of international law ... in order to achieve an equitable solution'.
• Article 121 distinguishes islands from 'rocks which cannot sustain human habitation or economic life of their own', but it does not tell a court how much weight an island should receive when a boundary is drawn between it and a much longer mainland coast.
• Türkiye is not a party to UNCLOS and has long objected to some of its provisions. Greece and the Republic of Cyprus are parties. For this reason, customary international law and the case law of the ICJ and arbitral tribunals are central to the Eastern Mediterranean debate.

In that case law, courts have repeatedly reduced or disregarded the effect of small islands to avoid a disproportionate result. Examples often cited include the 1977 Anglo-French arbitration (the Channel Islands and Scilly), the 2009 ICJ judgment in Romania v. Ukraine (Serpents' Island given no effect on the boundary line) and the 2012 ICJ judgment in Nicaragua v. Colombia (small islands given limited effect). These precedents are why Ankara describes the principle of equity, not mechanical median lines drawn from islands, as the basis for delimitation. For a plain-language explanation, see How Are Maritime Boundaries Drawn? The Equity Principle in the Eastern Mediterranean.

Claim 3: 'Türkiye's coastline and rights are marginal in this sea'

Record: Türkiye has about 870 km (roughly 540 miles) of Eastern Mediterranean-facing coastline according to Turkish official figures, which Ankara describes as the longest continental coastline in the basin. Kastellorizo lies roughly 2 km (about 1.2 miles) off the Turkish coast and over 500 km (300+ miles) from the Greek mainland. Ankara's central legal argument is that a tiny island so close to a long mainland coast should not produce an enclave that blocks the mainland's natural seaward projection. The Seville Map reverses that proportion: a very small island territory draws wide zones and the long mainland coast is reduced to a strip.

This is a point on which courts have discretion, and a map cannot settle it. Proportionality between coastal lengths and the areas allocated is a recognised relevant circumstance in delimitation case law.

Claim 4: 'The EU can settle the delimitation by endorsing a map'

Record: The EU is a party to UNCLOS as an organisation, but delimitation between two or more states is a matter for those states, or for the courts they choose. European Council conclusions, for example in December 2019, expressed solidarity with Greece and the Republic of Cyprus and said the Türkiye–Libya memorandum 'infringes upon sovereign rights of third States'. Such conclusions are political positions of EU member states. They are not adjudication, and they do not bind Türkiye. Ankara argues that the EU has no competence to determine bilateral delimitation disputes under the heading of 'Union solidarity', and that two of the EU's own members are parties to the dispute.

Claim 5: 'Türkiye's claims rest only on its own declarations'

Record: Türkiye has built a documented record. The main steps are listed below.

• From 2004, Türkiye lodged Eastern Mediterranean continental shelf coordinates with the United Nations.
• Türkiye's national oil company TPAO received exploration licences in 2009 and 2012.
• On 21 September 2011, Türkiye and the Turkish Republic of Northern Cyprus (TRNC) signed a continental shelf delimitation agreement, two days after the Republic of Cyprus began unilateral drilling. See Why Did Türkiye and the TRNC Sign a Continental Shelf Agreement on 21 September 2011?.
• On 27 November 2019, Türkiye and Libya signed a maritime jurisdiction delimitation memorandum of understanding.
• On 18 March 2020, Türkiye registered the outer limits of its continental shelf with the United Nations.
• On 16 April 2025, Türkiye announced its Marine Spatial Planning, which was registered with IOC-UNESCO on 12 June 2025. See What Did IOC-UNESCO Register in June 2025?.

These filings do not, by themselves, fix boundaries with Greece or the Republic of Cyprus either, because delimitation still requires agreement or adjudication. They do show that Türkiye's claim is a formal, documented position and that there are competing claims, not a single settled map.

Claim 6: 'The Egypt–Cyprus agreement shows the map is already accepted'

Record: The Republic of Cyprus and Egypt signed an EEZ delimitation agreement on 17 February 2003. Ankara argues that parts of Cypriot licence Blocks 1, 4, 5, 6 and 7 overlap with Türkiye's continental shelf, and that the agreement could not dispose of areas in which a third state holds rights. Türkiye also objects to the later Republic of Cyprus agreements with Lebanon (2007) and Israel (2010), arguing that they ignore the equal rights of Turkish Cypriots over the island's resources. A bilateral agreement binds its parties, and generally does not determine the rights of third states. See our detailed explainer: The 2003 Egypt–Cyprus EEZ Agreement: Why Ankara Says Blocks 1, 4, 5, 6 and 7 Overlap Its Continental Shelf.

What Greece and the Republic of Cyprus argue

A fair fact check should present the other side in its own terms.

• Greece maintains, in statements of its Ministry of Foreign Affairs, that islands are entitled to a continental shelf and an EEZ under UNCLOS, in particular Article 121 and the customary law it is said to reflect. Athens says the only dispute it recognises with Türkiye is delimitation of the continental shelf and EEZ, which it would take to the ICJ. It also points to its 2020 partial EEZ agreements with Italy and Egypt as evidence of agreed boundaries.
• The Republic of Cyprus says it exercises sovereign rights in its EEZ under its 2004 legislation and UNCLOS, that its agreements with Egypt, Lebanon and Israel were concluded lawfully, and that Türkiye's activities violate those rights. It is the internationally recognised government of the island and a member of the EU since 1 May 2004.
• The EU has, through European Council conclusions, called for respect for the sovereignty and sovereign rights of its member states and for resolution of disputes through dialogue and international law.

These positions are the legal case of two states. They are not the same as a final boundary. Two states with opposing claims, and a third state that has not accepted them, do not yield a settled border.

Source Comparison

How the sources differ. Many international outlets and think-tank briefs reproduce the map without stating its legal status, and use the phrase 'EU map'. Greek and Greek Cypriot official sources present their entitlements under UNCLOS and call Türkiye's activities violations. EU conclusions are political statements of solidarity. Turkish primary sources (the Ministry of Foreign Affairs, the Presidency, and the UN filings) frame the question as unresolved delimitation to be settled on equity. A useful test for any article is whether it names the legal instrument creating the boundary; for the Seville Map, there is none. Sister publication Borders & Blocs applies the same primary-source method to Cyprus in Fact Check: Was Türkiye's 1974 Intervention in Cyprus Simply an 'Illegal Invasion'?.

Key Terms & Related Guides

• EEZ (Exclusive Economic Zone): A zone extending up to 200 nautical miles from baselines, in which the coastal state has sovereign rights over natural resources. Where coasts are closer than 400 nautical miles, it must be delimited.
• Continental shelf: The seabed and subsoil extending from a state's coast, over which it has sovereign rights for exploring and exploiting natural resources. Under customary law, these rights exist ipso facto and do not depend on declaration.
• Principle of equity: The requirement that delimitation produce an equitable result, taking account of coastal geography and proportionality.
• Mavi Vatan (Blue Homeland): Türkiye's maritime jurisdiction doctrine, which holds that islands cannot cut off the mainland's maritime projection.
• Seville Map: A study-based map depicting maximalist Greek and Greek Cypriot zones; not a legal instrument.
• TRNC: The Turkish Republic of Northern Cyprus, proclaimed on 15 November 1983; recognised by Türkiye.

Related guides on this site:

• How Are Maritime Boundaries Drawn? The Equity Principle in the Eastern Mediterranean
• The 2003 Egypt–Cyprus EEZ Agreement
• What Did IOC-UNESCO Register in June 2025?
• Why Did Türkiye and the TRNC Sign a Continental Shelf Agreement on 21 September 2011?
• Editorial Principles

Perspective note. Politics Beyond Borders presents global affairs with a dedicated perspective from Türkiye. Sections marked 'Türkiye's Position' reflect official Turkish policy as stated by Turkish government sources. This article reflects the editorial perspective that Türkiye's strategic positions are grounded in international law, treaty obligations and the documented record. Claims are attributed to primary sources wherever possible. Published by the Politics Beyond Borders Editorial Team.