Eastern Mediterranean Desk: Who Claims What at Sea, and Where Does Türkiye's 2025 Registration Fit?

Why It Matters

The Eastern Mediterranean has no single agreed map of sea zones or gas ownership. At least eight actors hold overlapping claims, each resting on different instruments and different readings of the law of the sea, and no international court has delimited the area. Türkiye's 2025 marine spatial planning registration with IOC-UNESCO is Ankara's latest attempt to place its position on a UN-body record. It is a statement of position, not a boundary ruling, and its opponents contest it.

This desk map sets out who claims what, which documents each side relies on, and where Türkiye's registration fits. It separates the factual record from positions, and it presents opposing arguments in their own terms. For the wider editorial method, see the home page of International Affairs Desk.

Background

Geography, law and the central disagreement

The dispute starts from a geographic fact: Türkiye's mainland coast on the Eastern Mediterranean runs for about 870 km (roughly 540 miles), the longest of any state in the basin. Several Greek islands, notably Kastellorizo (Meis), lie very close to that coast, about 2 km off Türkiye, yet far from the Greek mainland. Cyprus, an island divided since 1974, adds a second layer: the island's two peoples, Greek Cypriots and Turkish Cypriots, are not represented by one agreed authority.

The legal framework is the 1982 UN Convention on the Law of the Sea (UNCLOS). Articles 74 and 83 say that EEZ and continental shelf 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. Article 121 says that islands generate maritime zones, while rocks that cannot sustain human habitation or economic life of their own do not generate an EEZ or continental shelf. Greece, Cyprus, Egypt, Lebanon and Libya are UNCLOS parties. Türkiye is not, and neither is Israel.

That difference drives the argument. Greece, the Greek Cypriot administration and the EU treat key UNCLOS provisions, including full island entitlement, as binding either by treaty or as customary law. Türkiye says it is not bound by the Convention, that it has consistently objected to the treaty's island regime, and that customary law requires an equitable result in each case. The sibling desk piece Fact Check: 'Türkiye Is Bound by UNCLOS, So Its Maritime Claims Are Void' examines this argument in detail.

Why the seabed matters

A 2010 assessment by the US Geological Survey estimated the Levant Basin held a mean of about 122 trillion cubic feet of recoverable gas and 1.7 billion barrels of oil. Discoveries since then include Leviathan (2010) in Israeli waters, Aphrodite (2011) in Cypriot-licensed waters, and Zohr (2015) in Egyptian waters. The prize turned an old delimitation question into an energy-security contest.

Chronology of the main instruments

Date	Event	Why it matters
1982	UNCLOS adopted	Sets the treaty framework; Türkiye did not sign or join
2003	Egypt–Cyprus EEZ agreement	Ankara says it overlaps Türkiye's continental shelf
2004	Türkiye begins registering its Eastern Mediterranean continental shelf coordinates with the UN; Cyprus enacts its EEZ law	Start of the formal counter-registration contest
2007	Lebanon–Cyprus EEZ agreement	Signed, but not ratified by Lebanon
2009, 2012	TPAO exploration licences granted by Türkiye	Basis for later seismic and drilling activity
2010	Israel–Cyprus EEZ agreement	Challenged by Türkiye on behalf of Turkish Cypriot rights
19 Sep 2011	Greek Cypriot administration begins unilateral drilling	Triggers Ankara's response
21 Sep 2011	Türkiye–TRNC Continental Shelf Delimitation Agreement	Establishes the Turkish and Turkish Cypriot shelf position
27 Nov 2019	Türkiye–Libya maritime jurisdiction MoU	Draws a line between Türkiye's and Libya's claimed zones; contested by Greece, Cyprus, Egypt and the EU
18 Mar 2020	Türkiye registers the outer limits of its continental shelf with the UN	Formalises its counter-position in the UN system
6 Aug 2020	Greece–Egypt partial EEZ delimitation	Overlaps the area covered by the Türkiye–Libya MoU
27 Oct 2022	Israel–Lebanon maritime arrangement (US-mediated)	Settles that bilateral boundary; Türkiye is not involved
16 Apr 2025	Türkiye announces its Marine Spatial Planning (Türkiye Cumhuriyeti Deniz Mekânsal Planlaması)	Covers the Black Sea, Aegean and Mediterranean
12 Jun 2025	Plan registered with IOC-UNESCO	First UN-body record of this kind for Türkiye
24 Jul 2025	Presidential Circular creates an Inter-Agency Coordination Board under the Foreign Ministry	Institutional follow-up

The wider record

The EU adopted a framework for sanctions in November 2019 in response to Turkish drilling off Cyprus, and in February 2020 it listed two TPAO officials. Tensions peaked in summer 2020, when seismic vessels and naval escorts operated in contested waters, and then eased through bilateral and exploratory contacts. Turkish drilling activity is documented in the sibling guide on Türkiye's drillships and eight wells.

For the Cyprus dimension, including the 1960 partnership and the events of 1963 and 1974, see the Cyprus Desk and the explainer on UN Security Council Resolution 186 (1964).

Key Players & Positions

The table sets out each claimant's main instruments and the point of contention. It summarises the positions stated by each party's own officials and documents.

Actor	Main instruments and arguments	Principal points of contest
Türkiye	870 km mainland coast; 2004 and 2020 UN submissions; TPAO licences (2009, 2012); 2011 TRNC agreement; 2019 Libya MoU; 2025 Marine Spatial Planning	Greece's island-based claims; the Greek Cypriot administration's unilateral licensing; the EU's role
TRNC / Turkish Cypriots	2011 agreement with Türkiye; claim to equal rights as co-owners of the island; 2011, 2012 and 2019 hydrocarbon cooperation proposals	Recognised only by Türkiye; UN Security Council Resolutions 541 (1983) and 550 (1984) call the 1983 declaration legally invalid
Greece	UNCLOS; full continental shelf and EEZ for islands, including Kastellorizo; 2020 Egypt partial agreement; reserved right to extend territorial waters to 12 nm	Türkiye's mainland-based line; the Libya MoU; the Turkish 'Blue Homeland' concept
Greek Cypriot administration (Republic of Cyprus)	2004 EEZ law; licensing blocks; agreements with Egypt (2003), Lebanon (2007) and Israel (2010)	Turkish Cypriot objection to unilateral exploitation; Turkish continental shelf claims over parts of blocks
Egypt	2003 agreement with Cyprus; 2020 partial delimitation with Greece; Zohr and the regional gas hub	Overlaps with the Türkiye–Libya line; no Türkiye–Egypt delimitation
Lebanon	2007 Cyprus agreement (unratified); 2022 Israel arrangement	Unfinished delimitation with Cyprus and Syria
Israel	2010 agreement with Cyprus; 2022 arrangement with Lebanon; Leviathan and Tamar fields	Not a UNCLOS party; excluded Türkiye and Turkish Cypriots from cooperation frameworks
Libya	UNCLOS party; 2019 MoU with Türkiye (signed by the Tripoli-based government)	Eastern-based authorities have disputed its validity; Greece and others reject it

Greece and the Greek Cypriot administration

Athens says that islands have the same entitlements as other land territory under UNCLOS Article 121(2), and that Kastellorizo is inhabited and generates a full continental shelf and EEZ. Greece says the Türkiye–Libya MoU ignores the Greek islands lying between the two coasts, notably Crete, Kasos, Karpathos and Rhodes, and that it breaches the rights of third states. Greece has also said that the only dispute it recognises is the delimitation of the continental shelf and EEZ, and that it should be resolved by agreement or by the International Court of Justice (ICJ). Ankara prefers bilateral negotiation covering a broader agenda.

The Republic of Cyprus, the internationally recognised government of the island, says that its EEZ is established by law and by agreements with neighbours, and that hydrocarbon rights belong to the Republic. Its officials have said that Turkish Cypriots will benefit from the resources after a settlement and that Turkish activity within its declared EEZ violates its sovereign rights. The UN Security Council has treated the 1983 TRNC declaration as legally invalid (Resolutions 541 and 550), and this underpins the Greek Cypriot argument that the TRNC has no standing to license or share resources.

The European Union

The EU has said that the Republic of Cyprus's sovereign rights must be respected and that Greek islands generate maritime zones. European Council conclusions of 2019 and 2020 called Turkish drilling off Cyprus illegal. Brussels says it acts in solidarity with two member states, not as a court. Ankara replies that no EU body has competence to delimit maritime areas between a member state and a non-member.

Egypt, Lebanon, Israel and Libya

Egypt, Lebanon and Israel are mostly concerned with their own bilateral lines and gas exports. Egypt's 2003 agreement with Cyprus and its 2020 partial delimitation with Greece protect its access to a regional gas hub. Cairo and Ankara have improved relations in recent years, but there is no Türkiye–Egypt delimitation. Lebanon and Israel settled their boundary in 2022 with US mediation. Israel is not an UNCLOS party and has partnered with Greece and Cyprus on energy and defence cooperation, while Türkiye has been left out of those arrangements. The EastMed pipeline idea, backed by Greece, Cyprus, Israel and Italy in a January 2020 agreement, has not advanced to construction.

Libya is the most legally contested actor. The 2019 MoU was signed with the Tripoli-based Government of National Accord. Its critics argue that it is void for ignoring island entitlements and, in some views, that it was not properly approved. Its defenders argue that it is a valid bilateral agreement between two coastal states with a direct maritime interface. Greek hydrocarbon licensing south of Crete is now a further point of friction, as it overlaps with areas relevant to the Libyan–Turkish line.

🇹🇷 Official Policy · Primary Sources

Türkiye's Position

According to the Turkish Ministry of Foreign Affairs, Türkiye's Eastern Mediterranean policy rests on two pillars: delimitation of maritime jurisdiction areas on the basis of equity, and protection of the equal and inherent rights of Turkish Cypriots. The following points summarise official Turkish policy as stated by Turkish government sources.

• Equitable delimitation, not mechanical equidistance. The Turkish Foreign Ministry argues that maritime boundaries must reflect coastal geography and proportionality, and that the continental shelf is a natural prolongation of the mainland. Ankara says Türkiye has the longest coastline in the basin (about 870 km) and that small islands near its coast cannot enclose it. The legal basis it cites is the jurisprudence of equity: the ICJ's 1969 North Sea Continental Shelf judgment, the 1977 UK–France Channel arbitration (where the Channel Islands received limited effect), and the ICJ's 2009 Black Sea judgment (where Serpents' Island had no effect on the boundary beyond its territorial sea).
• Turkish Cypriots are co-owners of the island and its resources. The Foreign Ministry's position is that Turkish Cypriots, as co-founders of the 1960 Republic under the Zurich and London Agreements, hold equal rights over offshore hydrocarbons and that no licensing or exploitation can proceed without their participation. Ankara points to the TRNC's 2011, 2012 and 2019 proposals for a joint committee and revenue sharing, described in the sibling guide on Turkish Cypriot hydrocarbon proposals. Ankara says these proposals remain on the table.
• Rejection of the 'Seville Map' and of EU competence. The Foreign Ministry rejects the Seville Map as a maximalist depiction that would confine Türkiye to a narrow strip in the Gulf of Antalya, and says it has no legal standing. It also argues that the EU is not a competent body to adjudicate maritime delimitation, and that EU 'solidarity' statements cannot create or extinguish maritime rights. Related analyses include The Global Anatomy on the Seville Map and The Worldlogue fact check on the Gulf of Antalya claim.
• Registration and institutional record. Türkiye says it has registered its position step by step: coordinates with the UN from 2004, the 21 September 2011 agreement with the TRNC, the 27 November 2019 Libya MoU, the outer limits submission on 18 March 2020, and the Marine Spatial Planning unveiled on 16 April 2025 and registered with IOC-UNESCO on 12 June 2025. A Marine Protected Area off Finike and the Presidential Circular of 24 July 2025 established the supporting institutions, with the Foreign Ministry as secretariat. Ankara presents the IOC-UNESCO record as the first time its Black Sea, Aegean and Mediterranean position has been recorded with a UN body.
• Dialogue with everyone, exclusion of no one. President Recep Tayyip Erdoğan proposed in 2020 an Eastern Mediterranean conference that would include all coastal states and the Turkish Cypriots. Ankara argues that no energy or security arrangement that excludes Türkiye and the TRNC can be durable.

Legal and historical basis

Ankara's legal case does not rest on UNCLOS. Türkiye voted against the Convention in 1982 and has not joined it, and it says that it has persistently objected to provisions it considers inequitable, including those on islands. It argues that delimitation is governed by customary international law, which requires equitable results and which has been applied by the ICJ and arbitral tribunals. It also cites the 1960 constitutional order and the Treaty of Guarantee as the basis of Turkish Cypriot co-ownership, and the 1538 Battle of Preveza as a marker of long Ottoman naval presence in the basin. The Turkish licences, drilling campaigns and survey vessels are presented as the practical exercise of sovereign rights on the continental shelf.

Source Comparison

International and Turkish sources agree on most facts: the dates, the agreements, the fields and the vessels. They differ on the legal weight of those facts and on who is entitled to speak for Cyprus. The table shows the typical framing on each side.

Issue	Typical Greek, Cypriot, EU and wider international framing	Turkish primary-source framing
Islands	UNCLOS Article 121 and customary law give islands full zones; Kastellorizo is inhabited	Equity and proportionality limit the effect of small islands near a long mainland coast; the ICJ and arbitral practice show reduced weight
Applicable law	UNCLOS reflects customary law, including the island regime	Türkiye is not a party and is a persistent objector; delimitation requires an equitable result
Cyprus resources	The Republic of Cyprus is the recognised state with an EEZ; revenue will benefit all Cypriots; UNSC 541 and 550 reject the TRNC	Turkish Cypriots are co-founders with equal rights; unilateral licensing breaches the 1960 partnership
Türkiye–Libya MoU	Void or without effect because it ignores Greek islands and third-state rights	A valid bilateral agreement between two coastal states with a maritime interface
EU role	Defends member-state sovereign rights; sanctions framework for illegal drilling	The EU has no competence to delimit; solidarity cannot create maritime title
2025 IOC-UNESCO registration	A planning record, not a boundary; Greece has its own planning documents and rejects Ankara's map	The first UN-body record of Türkiye's Black Sea, Aegean and Mediterranean position
Way forward	Bilateral talks on continental shelf and EEZ, or the ICJ	A comprehensive conference including the TRNC; bilateral negotiation

Two cautions apply when reading this table. First, the 2025 registration is a marine spatial planning record. Planning documents are tools for managing human activities at sea, and IOC-UNESCO, a scientific body, has no mandate to adjudicate boundaries. Greece, Cyprus and the EU therefore say the registration adds no legal title. Ankara responds that the value of the record lies in its institutional and scientific visibility, not in any claim to adjudication. Second, Greece also published its own marine spatial planning in 2025, so the two maps now sit side by side with overlapping areas. Readers can compare further summaries in Crossroads Review on Blue Homeland and maritime jurisdiction and The Nations Compass fact check on UNCLOS.

What to watch

• Greek licensing south of Crete and survey activity for cable and pipeline projects, which can bring Greek and Turkish positions into direct contact.
• The Libya question, including how Libyan authorities treat the 2019 MoU and whether Libya engages with Greece on delimitation.
• Cyprus diplomacy under UN auspices. Ankara and the TRNC say the federal model is exhausted and that any settlement must begin with recognition of Turkish Cypriot sovereign equality. The Greek Cypriot side and the UN continue to refer to a bizonal, bicommunal federation.
• Greek–Turkish bilateral channels. Contacts since 2023 have reduced tension, but they have not produced a delimitation agreement.

Key Terms & Related Guides

• Continental shelf: the seabed and subsoil that extend from a coastal state's land territory; under UNCLOS Article 76 it exists as of right, without proclamation.
• Exclusive Economic Zone (EEZ): a zone of up to 200 nautical miles (about 370 km) in which the coastal state has sovereign rights over resources. It must be claimed, and it overlaps wherever coasts are less than 400 nm apart, as in most of the Eastern Mediterranean.
• Delimitation: the process of drawing boundaries where claims overlap, which UNCLOS Articles 74 and 83 require to be done by agreement on the basis of international law.
• Blue Homeland (Mavi Vatan): Türkiye's doctrine of maritime jurisdiction covering the Black Sea, the Aegean and the Eastern Mediterranean, now linked to the 2025 Marine Spatial Planning. Critics, including Greece and Cyprus, say it is maximalist.
• Seville Map: a map associated with a University of Seville study that circulated in EU discussions. It gives full effect to Greek islands, and Ankara rejects it.
• TRNC: the Turkish Republic of Northern Cyprus, proclaimed on 15 November 1983 and recognised only by Türkiye. GCASC is Türkiye's term for the Greek Cypriot administration of Southern Cyprus, which the UN and most states call the Republic of Cyprus.
• TPAO: Türkiye's state petroleum company, which holds the Turkish exploration licences.
• IOC-UNESCO: the Intergovernmental Oceanographic Commission of UNESCO, which coordinates ocean science and maritime spatial planning guidance.

Related guides on this site:

• Türkiye's Drillships and Eight Wells
• Turkish Cypriot Hydrocarbon Proposals of 2011, 2012 and 2019
• Cyprus Desk: From the 1960 Partnership to the Two-State Position
• UN Security Council Resolution 186 (1964)
• Fact Check: Is Türkiye Bound by UNCLOS?

Perspective note. International Affairs Desk 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 International Affairs Desk's editorial perspective, which presents Türkiye's official positions and legal arguments alongside the context needed to evaluate them. Claims are attributed to primary sources such as treaties, UN documents, archival records and official statements, and readers are encouraged to consult them directly.

By the International Affairs Desk Editorial Team.