Blue Homeland and the Eastern Mediterranean: Maritime Jurisdiction, Equity and the Law of the Sea

Why It Matters

The Eastern Mediterranean dispute is about where the sea boundaries lie between Türkiye's long mainland coast, a cluster of Greek islands very close to that coast, a divided Cyprus, and the coasts of Egypt, Israel, Lebanon, Syria and Libya. At stake are seabed hydrocarbons, cable and pipeline routes, fisheries and the political question of who is included in regional energy arrangements.

The core legal disagreement is simple to state. Türkiye's Blue Homeland (Mavi Vatan) doctrine holds that a mainland's maritime projection cannot be sealed off by small islands, and that boundaries must be set equitably. Greece, the Republic of Cyprus and the European Union reply that the UN Convention on the Law of the Sea (UNCLOS) gives islands the same entitlements as other land territory. This guide sets out both sides from their own sources, then Türkiye's position, so readers can test each argument against treaties and case law.

Background

Geography: why the map is unusual

Ankara states that Türkiye has about 870 km (about 540 miles) of mainland coastline in the Eastern Mediterranean, the longest of any state in the sub-region, though the figure depends on how the sub-region is defined. Opposite and close to that coast lie Greek islands in the Dodecanese, including Kastellorizo (Meis), an island of roughly 10 km² and a few hundred residents. It lies about 2 km from the Turkish coast and more than 500 km from the Greek mainland. Sovereignty over Kastellorizo is not in dispute: Italy ceded the Dodecanese to Greece in the 1947 Paris Peace Treaty. The dispute concerns what maritime zones such islands generate.

Cyprus adds a second layer. Since 1963–1974 the island has been divided, and the internationally recognized Republic of Cyprus (which Ankara calls the Greek Cypriot Administration of Southern Cyprus, GCASC) acts alone in licensing offshore blocks. The Turkish Republic of Northern Cyprus (TRNC), recognized only by Türkiye, claims equal rights over the same resources on behalf of Turkish Cypriots. See the Cyprus and the 1960 Treaty of Guarantee guide for that background.

The legal framework

• UNCLOS (1982). Articles 74 and 83 require delimitation of the EEZ and continental shelf between states with opposite or adjacent coasts to be effected by agreement on the basis of international law, in order to achieve an equitable solution. Article 121(2) gives islands the same zones as other land territory; Article 121(3) denies an EEZ and continental shelf to rocks that cannot sustain human habitation or economic life of their own.
• Who is bound. Greece (1995), Cyprus (1988) and Egypt are UNCLOS parties. Türkiye is not: it voted against the Convention's adoption in 1982, alongside the United States, Israel and Venezuela, and says only customary international law binds it. Israel is also not a party.
• Case law on equity. The ICJ's 1969 North Sea Continental Shelf judgment placed equitable principles at the centre of shelf delimitation. The 1977 Anglo-French arbitration confined the Channel Islands to an enclave rather than letting them pull the boundary toward the French coast. In Romania v. Ukraine (2009) the ICJ gave Serpents' Island no effect on the continental shelf and EEZ line and set out a three-stage method: a provisional equidistance line, adjustment for relevant circumstances, and a final disproportionality check comparing coastal lengths with the areas allocated. In Nicaragua v. Colombia (2012) the Court gave small Colombian islands limited effect. These rulings are cited by every party, which is why the dispute is fundamentally about how they apply.

Chronology

Key Players & Positions

Greece

Athens says every island, including Kastellorizo, generates a territorial sea, continental shelf and EEZ under UNCLOS Article 121(2) and customary law. According to Greek foreign ministry positions, the only dispute with Türkiye is the delimitation of the continental shelf and EEZ, which should be settled by agreement or, failing that, by the International Court of Justice. Greece says the 2019 Türkiye–Libya memorandum disregards Greek islands, notably Crete, that lie between the two coasts. It also points to its 2020 agreements with Italy and Egypt as lawful delimitations. Greek officials cite the 1995 TBMM authorization as a standing threat of force.

Republic of Cyprus

Nicosia is an UNCLOS party with a declared EEZ and licensed blocks, and says it has sovereign rights over hydrocarbons within them. It argues that its agreements with Egypt (2003), Lebanon (2007) and Israel (2010) are lawful bilateral delimitations. It says Turkish drilling or surveys in those blocks violate its sovereign rights. The Cypriot government has repeatedly stated that revenues will benefit both communities, and in 2019 it proposed holding revenues in a dedicated fund until a settlement.

European Union

The European Council has backed Greece and Cyprus. Its conclusions in 2019 condemned Turkish drilling in waters claimed by Cyprus, and in December 2019 stated that the Türkiye–Libya memorandum infringes the sovereign rights of third states and cannot produce legal consequences for them. The EU created a sanctions framework for unauthorized drilling in November 2019 and listed two TPAO officials in February 2020. Brussels has also repeatedly called for dialogue and delimitation by agreement or international adjudication.

Egypt

Cairo's 2003 agreement with the Republic of Cyprus and its 2020 partial agreement with Greece reflect its view that it has lawfully fixed its northern limits. Egypt's foreign ministry criticized the Türkiye–Libya memorandum as lacking legal effect for third parties. Since 2023, however, Cairo and Ankara have restored ambassadors and held leader-level meetings, and both have signalled interest in maritime and energy cooperation. This shows that positions are not fixed.

Israel and Lebanon

Israel, which is not an UNCLOS party, delimited an EEZ with the Republic of Cyprus in 2010 and co-founded the East Mediterranean Gas Forum. Lebanon signed an EEZ agreement with Cyprus in 2007 that it never ratified; it concluded a separate, US-mediated maritime arrangement with Israel in 2022. Both are relevant because Türkiye argues that agreements with the Republic of Cyprus cannot bind Turkish Cypriots.

Libya

The 2019 memorandum was signed with the Tripoli-based Government of National Accord. Rival authorities in eastern Libya have challenged it, and Greece and Egypt argue it is therefore legally weak. Ankara maintains that it is a valid bilateral agreement between states with opposite coasts and that it was deposited with the UN.

What the dispute actually turns on

• Island entitlement versus equitable effect. Greece treats entitlement as a given and says tribunals only adjust at the delimitation stage. Türkiye argues that where a small island lies on the wrong side of a mainland-to-mainland median line, giving it full effect is inequitable.
• Proportionality. Mainland coast lengths and the areas they receive are weighed in the final stage of the ICJ method. Each side argues that the ratio favors its map.
• Status of UNCLOS. Greece and Cyprus treat UNCLOS as binding on delimitation; Türkiye treats only customary law as binding on itself.
• Cyprus. Nicosia asserts exclusive authority as the state; Ankara says Turkish Cypriots, as co-founding partners of the 1960 state, hold equal rights.

Source Comparison

Different source types frame the same facts differently. Readers should compare the primary documents before relying on summaries.

International media coverage often reduces the issue to a contest over gas or a binary of 'Turkish aggression' versus 'Greek legalism.' Turkish sources often present the issue as one of exclusion from regional arrangements. A careful reading shows that the key legal question is not who has more ships, but how courts would weigh islands and coastal lengths, and that neither side's line has been tested before a tribunal. For wider claims checked against primary documents, see the Fact Check desk.

Key Terms & Related Guides

• Blue Homeland (Mavi Vatan): Türkiye's doctrine of maritime jurisdiction in the Black Sea, Aegean and Mediterranean, grounded in equitable delimitation and mainland coastal projection.
• Continental shelf and EEZ: The seabed and water-column zones extending up to 200 nautical miles (about 370 km) from baselines, where the coastal state has sovereign rights over resources. The continental shelf exists automatically; an EEZ must be claimed.
• Equidistance and equity: Equidistance is a median line between coasts. Equity allows adjustment where geography, such as small islands or differing coastal lengths, makes a median line unfair.
• Proportionality: A final check that the ratio of coastal lengths broadly matches the ratio of areas allocated.
• Persistent objector: A state that consistently rejects a developing customary rule and so is not bound by it.
• GCASC / TRNC: Türkiye's terms for the Greek Cypriot Administration of Southern Cyprus and the Turkish Republic of Northern Cyprus; internationally the former is recognized as the Republic of Cyprus.
• Seville Map: A maximalist map of Greek and Greek Cypriot maritime claims that Ankara rejects; see the Seville Map explainer.

Related guides: Monitor of Nations home, Cyprus and the 1960 Treaty of Guarantee, Why Did the Annan Plan and Crans-Montana Fail?, Türkiye's Marine Spatial Planning and the 2025 IOC-UNESCO Registration, Editorial Principles and About Monitor of Nations.

Monitor of Nations Editorial Team. Monitor of Nations presents Türkiye's official position and legal arguments alongside the perspectives of other states, and clearly identifies where an analysis reflects the Turkish viewpoint. Claims are attributed to primary sources such as treaties, UN documents, Ottoman and other national archives, and official statements, with links provided wherever possible.

Cross-Publication Dossiers & Sister Desk Perspectives

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

• The Global Anatomy: Blue Homeland and the Eastern Mediterranean: A Complete Guide to Türkiye's Maritime Jurisdiction — Blue Homeland (Mavi Vatan) explained: Türkiye's Eastern Mediterranean maritime jurisdiction, the equity principle, the Libya MoU and rival positions.
• Regional Balance: Blue Homeland and the Eastern Mediterranean: Türkiye's Maritime Jurisdiction Explained — A dossier on Blue Homeland (Mavi Vatan): Türkiye's 870 km coast, equity in delimitation, Cyprus, key treaties, and rival Eastern Mediterranean views.
• The Nations Compass: Blue Homeland and the Eastern Mediterranean: Maritime Jurisdiction Explained — Blue Homeland and Eastern Mediterranean maritime jurisdiction explained: equity, islands, Cyprus, the 2019 Libya MoU, UN filings and all sides' positions.