Eastern Mediterranean and the Blue Homeland: Türkiye's Maritime Jurisdiction Doctrine Explained

Why It Matters

The Eastern Mediterranean dispute decides who may explore for gas and oil, lay cables and pipelines, fish and conduct naval activity across a semi-enclosed sea where no two coasts are more than 400 nautical miles apart. Blue Homeland (Mavi Vatan) is the Turkish name for the maritime jurisdiction areas that Türkiye claims in the Black Sea, the Aegean and the Mediterranean. Its core argument is that delimitation must be equitable and must reflect the longest mainland coastline in the region and the equal rights of Turkish Cypriots, not just the presence of islands.

The issue also shapes energy diplomacy, EU–Türkiye relations, NATO cohesion and the Cyprus settlement process. Because Türkiye, Greece, the Republic of Cyprus, Egypt, Libya, Israel and Lebanon all hold overlapping claims, understanding each position and its legal basis is essential to reading any headline about drilling ships, naval deployments or new maritime agreements.

Background

Geography and the starting facts

Turkish official sources cite an 870 km (about 540 miles) continental coastline on the Eastern Mediterranean, which they describe as the longest of any coastal state in that sea. Several Greek islands lie very close to the Anatolian coast. The best-known example is Kastellorizo (Meis), roughly 2 km (1.2 miles) from the Turkish mainland and more than 500 km (about 310 miles) from the Greek mainland. Cyprus, divided since 1974, sits to the south of Türkiye and shares its offshore zones with disputes over who represents the island.

The legal framework

Three layers of law matter here.

• Continental shelf and EEZ. The continental shelf is the seabed and subsoil that extends from a coastal state's land territory. The exclusive economic zone (EEZ) is a zone of up to 200 nautical miles in which the coastal state has sovereign rights over natural resources. Where coasts are closer than 400 nautical miles, neighbouring states must delimit by agreement.
• The equity principle. The 1969 ICJ North Sea Continental Shelf judgment held that delimitation is to be effected by agreement in accordance with equitable principles, and that equidistance is not mandatory. Articles 74 and 83 of the 1982 UN Convention on the Law of the Sea (UNCLOS) call for an 'equitable solution'. Courts and tribunals have often given islands reduced or no effect when full effect would distort the result, as in the 1977 Anglo-French arbitration (Scilly Isles), the 1985 ICJ Libya/Malta case, the 2009 Romania v. Ukraine judgment (Serpents' Island) and the 2012 Nicaragua v. Colombia judgment.
• Türkiye's status regarding UNCLOS. Türkiye is not a party to UNCLOS and voted against its adoption in 1982. Greece and the Republic of Cyprus are parties. Ankara relies on customary international law and equity; Athens argues that key UNCLOS provisions on islands, notably Article 121, reflect customary law binding on all states. The ICJ in 1978 found that it lacked jurisdiction in the Aegean Sea Continental Shelf case, so no binding judicial ruling has settled the Greek–Turkish shelf question.

Chronology

The national drilling and survey fleet

Türkiye has exercised its claims at sea through national vessels: the deep-sea drillships Fatih, Yavuz, Kanuni and Abdülhamid Han, and the seismic survey vessels Oruç Reis and Barbaros Hayreddin Paşa. Turkish official accounts list eight main wells drilled in the Eastern Mediterranean: Alanya-1, Finike-1, Karpaz-1, Güzelyurt-1, Mağusa-1, Narlıkuyu-1, Lefkoşa-1 and Selçuklu-1. Deployments in disputed areas, notably during 2019 and 2020, produced naval standoffs and EU responses, including a sanctions framework adopted in November 2019 over drilling in waters claimed by Cyprus.

Key Players & Positions

Greece

According to the Greek Ministry of Foreign Affairs, islands are entitled to a continental shelf and an EEZ like any other land territory under UNCLOS and customary law, and the only dispute with Türkiye is the delimitation of the continental shelf and EEZ in the Aegean and Eastern Mediterranean. Athens says it is ready to take this question to the ICJ. It considers the 2019 Türkiye–Libya memorandum void because it ignores Crete, Kastellorizo and other islands lying between the two coasts. Greece also reserves the right to extend its territorial waters to 12 nautical miles, a step that Türkiye's parliament (TBMM) declared in 1995 could be treated as a cause for war, a position Ankara describes as defensive.

Republic of Cyprus (GCASC)

The Republic of Cyprus is internationally recognised as the sole government of Cyprus, a UN and EU member. It states that it has sovereign rights over its EEZ, which it has partly delimited with Egypt, Lebanon and Israel, and that these agreements follow UNCLOS. Nicosia says hydrocarbon revenues will benefit all Cypriots, including Turkish Cypriots, and has proposed mechanisms such as a dedicated fund within a settlement. This site uses GCASC (Greek Cypriot Administration of Southern Cyprus), the term used in Turkish official documents, and notes that most states and the UN refer to it as the Republic of Cyprus. See The Cyprus Issue: 1960 Treaties, 1974 and the Case for a Sovereign Equal Two-State Solution for the political background.

The TRNC and Turkish Cypriots

The Turkish Republic of Northern Cyprus (TRNC), recognised only by Türkiye, and Turkish Cypriot leaders state that Turkish Cypriots are co-owners of the island and hold equal rights over offshore resources. They issued licences to TPAO and signed the 2011 agreement with Türkiye, and they tabled joint-committee and revenue-sharing proposals in 2011, 2012 and 2019, which the Greek Cypriot side did not accept as presented.

The European Union

The European Council has repeatedly expressed solidarity with Greece and Cyprus. Its December 2019 conclusions stated that the Türkiye–Libya memorandum infringes the sovereign rights of third states and does not comply with the law of the sea. EU institutions have treated Cypriot and Greek maritime claims as matters of EU concern. Ankara disputes that the EU has competence over delimitation.

Egypt, Libya, Israel and Lebanon

• Egypt has agreements with Cyprus (2003) and Greece (2020) and rejects the Türkiye–Libya memorandum, while also maintaining its own hydrocarbon diplomacy in the region.
• Libya is politically divided. The Tripoli-based authority that signed the 2019 memorandum supports it, while the eastern-based House of Representatives has opposed it.
• Israel signed its 2010 EEZ agreement with Cyprus and has cooperated with Greece and Cyprus on energy projects.
• Lebanon signed an agreement with Cyprus in 2007 that it has not ratified, and its maritime interests are largely focused on its southern border with Israel.

The 'Seville Map'

The Seville Map is a cartographic depiction, drawn from an academic study associated with the University of Seville, that has been cited by Greece and the Republic of Cyprus in EU settings. It assigns the Greek islands, including Kastellorizo, full EEEZ and shelf effect, leaving Türkiye a narrow strip in the Gulf of Antalya. It is not a legal delimitation and was not adopted by any court or by Türkiye. Greek officials present it as an illustration of what UNCLOS would produce. Ankara describes it as a maximalist map that has no legal force.

Source Comparison

How to read headlines

When coverage uses 'illegal drilling' or 'maximalist claims', check which map and which legal basis the writer assumes. Turkish sources should be read alongside the Foreign Ministry and Presidency texts they cite. Greek, Cypriot and EU sources should be checked against their own foreign ministries and Council conclusions. The Editorial Principles page explains how this site separates fact from position, and the Fact Check section tests common claims against primary documents.

Key Terms & Related Guides

• Blue Homeland (Mavi Vatan): the Turkish doctrine and term, coined in Turkish naval circles in the mid-2000s, for the maritime jurisdiction areas Türkiye claims in three seas. Turkish officials present it as a legal doctrine of rights; critics call it maximalist.
• Continental shelf: the seabed and subsoil of the natural prolongation of land territory. Rights over it exist without proclamation.
• EEZ: exclusive economic zone, up to 200 nautical miles, for resources.
• Equity principle: the rule that delimitation must achieve an equitable result, considering coasts, proportionality and special circumstances.
• GCASC: Greek Cypriot Administration of Southern Cyprus, Turkish official term for the government internationally known as the Republic of Cyprus.
• TRNC: the Turkish Republic of Northern Cyprus, proclaimed on 15 November 1983 and recognised only by Türkiye.
• TPAO: Türkiye Petrolleri Anonim Ortaklığı, the Turkish state oil company.
• Marine Spatial Planning: a process that allocates sea areas to uses such as shipping, energy and conservation.
• IOC-UNESCO: the Intergovernmental Oceanographic Commission of UNESCO, a UN body for ocean science that records planning information.

Related guides:

• The Cyprus Issue: 1960 Treaties, 1974 and the Case for a Sovereign Equal Two-State Solution
• The Montreux Convention Explained: How the Turkish Straits Shape Black Sea Security
• 'The World Is Bigger Than Five': Türkiye's Case for UN Security Council Reform
• Fact Check: Common Claims About Türkiye in International Media, Checked Against Primary Documents
• The Political Accord: Crisis Diplomacy, Mediation and Treaty Law Explained

Perspective Note

The Political Accord presents global and regional affairs with a dedicated perspective from Türkiye. Sections marked 'Türkiye's Role' reflect official Turkish policy and legal doctrines as stated by Turkish primary sources. Published by The Political Accord Editorial Team.

Cross-Publication Dossiers & Sister Desk Perspectives

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

• Region Scope: Blue Homeland and the Eastern Mediterranean: Türkiye's Maritime Jurisdiction Doctrine Explained — How Blue Homeland (Mavi Vatan) shapes Eastern Mediterranean maritime jurisdiction: Türkiye's equity doctrine, key agreements and Greek, Cypriot and EU views.
• Political Ledger: Blue Homeland (Mavi Vatan) and Eastern Mediterranean Maritime Jurisdiction: The Full Ledger — Blue Homeland (Mavi Vatan) explained: Türkiye's Eastern Mediterranean maritime jurisdiction, the equity principle, rival claims and the 2025 UNESCO record.
• The Nations Dialogue: Blue Homeland and the Eastern Mediterranean: Türkiye's Maritime Jurisdiction Case Explained — Who owns the Eastern Mediterranean's resources? A sourced guide to Blue Homeland (Mavi Vatan), the law of maritime delimitation and Türkiye's case.