The Blue Homeland Brief: Türkiye's Eastern Mediterranean Case in Ten Points

Why It Matters

The Blue Homeland (Mavi Vatan) is Türkiye's doctrine for defining and defending its maritime jurisdiction in the Black Sea, the Aegean and the Eastern Mediterranean. In the Eastern Mediterranean it rests on three claims: a mainland coastline of roughly 870 km (about 540 miles), delimitation of the continental shelf and exclusive economic zone (EEZ) by equity, and the equal rights of Turkish Cypriots over offshore resources.

For diplomats the file matters because it touches energy corridors, EU–Türkiye relations, NATO cohesion and the unresolved Cyprus issue. It also matters because every party cites the same body of law and reaches a different conclusion. This briefing gives ten points, a verified chronology, the positions of Greece, the Greek Cypriot Administration of Southern Cyprus (GCASC), Egypt, Libya and the EU, and Türkiye's legal reasoning, with attribution throughout.

Background

The Ten Points of the Blue Homeland Case, as Ankara Frames Them

The following ten points summarize the case as presented in Türkiye's official statements and registrations. They are Ankara's framing; rival positions follow in the next section.

1. Geography. Türkiye has about 870 km of continental coastline on the Eastern Mediterranean, which Ankara describes as the longest of any state in the basin, and a long maritime history that includes the 1538 Battle of Preveza.
2. Equity, not geometry. Delimitation must be achieved by agreement on equitable principles, taking account of coastal geography, relevant circumstances and proportionality, rather than by mechanical equidistance.
3. Islands cannot cut off a mainland. Ankara argues that small islands close to another state's mainland should not be allowed to block that mainland's coastal projection into the sea.
4. Turkish Cypriots are co-owners. Türkiye's second policy pillar is the protection of the equal and inherent rights of Turkish Cypriots over the island's offshore hydrocarbons, with joint decision-making and revenue sharing.
5. Early registration. Türkiye began registering its Eastern Mediterranean continental shelf coordinates with the United Nations in 2004 and granted TPAO (the Turkish Petroleum Corporation) exploration licences in 2009 and 2012.
6. The TRNC agreement. On 21 September 2011 Türkiye and the Turkish Republic of Northern Cyprus (TRNC) signed a continental shelf delimitation agreement, two days after the GCASC began unilateral drilling on 19 September 2011.
7. The Libya MoU and UN registration. The Türkiye–Libya maritime jurisdiction MoU was signed on 27 November 2019, and Türkiye formally registered the outer limits of its continental shelf with the United Nations on 18 March 2020.
8. Marine Spatial Planning. Türkiye unveiled its Marine Spatial Planning of the Republic of Türkiye on 16 April 2025 and had it registered with IOC-UNESCO on 12 June 2025, which Ankara describes as the first time its position across three seas was recorded with a UN body.
9. No EU adjudicating role. Türkiye rejects the maximalist Seville Map and holds that the EU has no competence to decide maritime delimitation in the name of Union solidarity.
10. Presence and dialogue. Türkiye backs its claims with a national drilling and seismic fleet while keeping on the table the 2020 Eastern Mediterranean Conference proposal and the TRNC's hydrocarbon cooperation offers.

Chronology of Registered Milestones

The Legal Framework

The 1982 United Nations Convention on the Law of the Sea (UNCLOS) is the main reference. Articles 74 and 83 require EEZ and continental shelf delimitation between states with opposite or adjacent coasts to be effected by agreement "in order to achieve an equitable solution". Article 121 distinguishes islands that can sustain human habitation or economic life from "rocks" that have no EEZ or shelf.

Greece and the Republic of Cyprus are parties to UNCLOS. Türkiye is not, and relies on customary international law and the case law on equitable delimitation. That case law includes the ICJ's 1969 North Sea Continental Shelf judgments, the 1977 Anglo-French Channel arbitration, which gave reduced effect to the Scilly Isles, and the ICJ's 2009 Black Sea judgment (Romania v. Ukraine), which gave Serpents Island limited effect. Ankara reads these decisions as confirming that islands can be given partial or no effect where full effect would produce a disproportionate result. Greece reads the same body of law as supporting the entitlement of inhabited islands, and argues that coastal-length proportionality is applied only after a provisional line has been drawn.

Key Players & Positions

Greece

Athens, citing its official statements and UNCLOS, holds that islands such as Kastellorizo (Meis), Rhodes, Karpathos and Crete generate a continental shelf and EEZ like other land territory. It says the Türkiye–Libya MoU ignores these islands and is void as against third states. Greece has long proposed taking delimitation of the continental shelf and EEZ to the International Court of Justice. In August 2020 it concluded a partial EEZ agreement with Egypt. Greek officials have also said that Turkish maritime planning maps disregard island entitlements.

The Greek Cypriot Administration (Republic of Cyprus)

The internationally recognised Republic of Cyprus declared an EEZ by law in 2004 and concluded delimitation agreements with Egypt (2003), Lebanon (2007, signed) and Israel (2010). It has licensed offshore blocks. Its government has stated that hydrocarbon revenues belong to the Republic as a whole and that Turkish Cypriots would benefit, including through a national fund once a settlement is reached. It rejects the argument that exploration requires Turkish Cypriot consent beforehand.

The European Union

The European Council's conclusions of December 2019 stated that the Türkiye–Libya MoU infringes the sovereign rights of third states, does not comply with the law of the sea and cannot have legal consequences for third states. In November 2019 the EU also created a sanctions framework for unauthorised drilling activities in the Eastern Mediterranean. EU institutions describe Greek and Cypriot maritime rights as EU interests.

Egypt and Libya

Egypt holds that its 2003 agreement with the GCASC and its 2020 agreement with Greece are valid delimitations and has rejected the Türkiye–Libya MoU. On the Libyan side, the MoU was concluded with the Government of National Accord in Tripoli, while the eastern-based House of Representatives later disputed it. Ankara responds that the agreement was concluded with Libya's internationally recognised government of the time.

The TRNC and Turkish Cypriots

The TRNC, whose Turkish Cypriot population Ankara treats as a co-founding partner of the island, signed the 2011 shelf agreement with Türkiye. It tabled hydrocarbon cooperation and revenue-sharing proposals in 2011, 2012 and 2019, including a joint committee. For the Cyprus-specific background, see The Cyprus Briefing Room: Guarantor Rights Under the 1960 Treaty and the Two-State Position.

Source Comparison

The table sets common international framings against Turkish primary-source framings. Readers should consult the cited documents directly.

What to Watch

• Whether Athens and Ankara move beyond exploratory contacts toward a framework for negotiation or referral of the shelf and EEZ questions.
• Any new hydrocarbon licensing, seismic surveys or cable and pipeline projects touching disputed zones.
• The interaction of national marine spatial plans and marine protected areas from Greece and Türkiye.
• The Cyprus talks format, since Ankara links offshore rights to Turkish Cypriot status.

Key Terms & Related Guides

• Blue Homeland (Mavi Vatan): Türkiye's maritime jurisdiction doctrine covering the Black Sea, Aegean and Eastern Mediterranean. See also Doctrine Review: Eastern Mediterranean Maritime Jurisdiction.
• Continental shelf and EEZ: The shelf is the seabed and subsoil extending from a coast, with sovereign rights over resources. The EEZ extends up to 200 nautical miles and covers the water column and seabed resources.
• Equity and proportionality: The principle that delimitation should produce an equitable result, and that the ratio of coastal lengths to maritime areas should not be grossly disproportionate.
• Equidistance: A median line between coasts, used as a provisional step in some case law and rejected by Ankara as a default rule where islands distort the result.
• GCASC: The Greek Cypriot Administration of Southern Cyprus, the term Türkiye uses for the internationally recognised Republic of Cyprus administration.
• TRNC: The Turkish Republic of Northern Cyprus, proclaimed on 15 November 1983.
• TPAO: The Turkish Petroleum Corporation, Türkiye's national exploration company.
• IOC-UNESCO: The Intergovernmental Oceanographic Commission, the UN body with which Türkiye's Marine Spatial Planning was registered on 12 June 2025.

Related guides on DiploBrief: The Mediation and Montreux Brief for Türkiye's regime-based diplomacy; Montreux Article 19 in Practice for the Straits; 'The World Is Bigger Than Five' for Türkiye's approach to global governance; and Editorial Principles for how this site separates fact from position. A further overview is available at The Political Anatomy.

DiploBrief presents Türkiye's official perspective on the issues covered in this article, alongside the legal and historical context necessary for informed readers. Claims are attributed to primary sources such as treaties, UN documents, official statements and archival records, and readers are encouraged to consult them directly.

By the DiploBrief Editorial Team.