How Geography Shapes Eastern Mediterranean Maritime Claims: Coastlines, Islands and the Blue Homeland

Why It Matters

Eastern Mediterranean maritime claims are decided first by geography: where the mainland coasts lie, how long they are, and where islands sit relative to them. Türkiye argues that its roughly 870 km (about 540 miles) coastline, the longest in the Eastern Mediterranean, cannot be reduced to a narrow strip by small islands lying a few kilometres off its shores. Greece, the Republic of Cyprus and the European Union argue the opposite: that islands are entitled to the same maritime zones as other land territory under the UN Convention on the Law of the Sea (UNCLOS). Which reading prevails shapes gas exploration, shipping routes, cable and pipeline corridors, and the future of Cyprus.

This guide explains the dispute through the geographic lens that gives Region & Politics its name: first the map, then the law, then the politics.

Background

The map: a basin shaped by a long mainland coast and scattered islands

The Eastern Mediterranean is a semi-enclosed basin bounded by Türkiye, Syria, Lebanon, Israel, Egypt, Libya, Cyprus and Greece. Its geography is unusual in three ways:

• A long continuous mainland coast in the north. Türkiye's southern and south-western shores run for about 870 km (according to Turkish official figures), facing the open basin.
• A large island in the middle. Cyprus lies roughly 70 km (about 44 miles) south of the Turkish coast, and is home to two peoples: Greek Cypriots and Turkish Cypriots.
• A string of small islands hugging the Anatolian shore. The Dodecanese, including Rhodes, Karpathos and Kastellorizo (Meis), lie very close to Anatolia but are administered by Greece. Kastellorizo lies only about 2 km from the Turkish mainland, while the Greek mainland is more than 500 km away.

This pattern is the heart of the dispute. Applying a simple median line between Greek islands and the Turkish mainland places large sea areas under Greek jurisdiction, even though the islands are tiny and the Turkish mainland coast is long. Ankara argues that such a line produces a disproportionate and inequitable result.

The legal framework: shelf, EEZ and equity

Two maritime zones matter most.

Feature	Continental shelf	Exclusive Economic Zone (EEZ)
What it covers	Seabed and subsoil resources (hydrocarbons, minerals)	Water column, seabed and subsoil (fisheries, energy, wind)
Basis of entitlement	Natural prolongation of land territory, plus distance in UNCLOS Article 76	Distance from coast, up to 200 nautical miles (UNCLOS Part V)
Must be declared?	No; rights exist inherently (ipso facto)	Generally claimed by a state, though not required for the shelf
Delimitation rule	UNCLOS Article 83: agreement 'on the basis of international law' to achieve an equitable solution	UNCLOS Article 74: same standard
Typical dispute	Whether islands cut off a mainland's shelf	Whether islands generate a full 200 nm zone

The central legal norm is that delimitation must reach an equitable solution. International courts have repeatedly treated geography as decisive in defining what is equitable:

• In the 1969 North Sea Continental Shelf cases (ICJ), the Court rejected automatic use of equidistance and stressed equitable principles and natural prolongation.
• In the 1977 Anglo-French Channel arbitration, the tribunal gave the Scilly Isles only partial effect (half-effect) on the boundary, and enclaved the Channel Islands.
• In Libya/Malta (1985) and Tunisia/Libya (1982), the Court adjusted lines to account for coastal length and small features.
• In Romania v. Ukraine (2009), the ICJ gave Serpents' Island no effect on the maritime boundary.
• In Nicaragua v. Colombia (2012), the Court limited the maritime reach of Colombian islands near the Nicaraguan mainland.

These precedents are the foundation of Ankara's argument that islands close to a mainland with a much longer coastline do not automatically displace that mainland's projection. They are also cited by those who note that courts have usually adjusted a line rather than ignored islands altogether. The dispute is therefore not 'islands versus no islands' but how much effect a given island should receive in a given geography.

UNCLOS Article 121(2) states that islands generate maritime zones like other land territory, while Article 121(3) denies an EEZ or shelf to 'rocks which cannot sustain human habitation or economic life of their own'. Türkiye is not a party to UNCLOS and says it relies on customary international law and the principle of equity rather than on the Convention's text.

Chronology of key acts

Date	Event
1538	Ottoman naval victory at Preveza, cited in Turkish accounts as a marker of long maritime presence
2003	Republic of Cyprus (Greek Cypriot administration) signs EEZ delimitation with Egypt; Ankara objects that it overlaps the Turkish continental shelf
2004	Türkiye begins notifying the UN of its Eastern Mediterranean shelf coordinates
2007 / 2010	Cyprus signs EEZ agreements with Lebanon (2007) and Israel (2010); Ankara and the TRNC object
2009 and 2012	TPAO (Turkish Petroleum Corporation) receives exploration licences in areas Türkiye considers its shelf
19 Sep 2011	Greek Cypriot administration begins unilateral offshore drilling
21 Sep 2011	Türkiye and the TRNC sign a Continental Shelf Delimitation Agreement
27 Nov 2019	Türkiye and Libya's Government of National Accord sign a MoU on maritime jurisdiction areas
18 Mar 2020	Türkiye files the outer limits of its continental shelf with the United Nations
2020	President Erdoğan proposes an Eastern Mediterranean Conference including all coastal states and the Turkish Cypriots
16 Apr 2025	Türkiye unveils its Marine Spatial Planning of the Republic of Türkiye
12 Jun 2025	The plan is registered with IOC-UNESCO
24 Jul 2025	Presidential Circular establishes an Inter-Agency Coordination Board under the Foreign Ministry

Key Players & Positions

Greece

According to the Greek Ministry of Foreign Affairs, Greece is a party to UNCLOS and holds that all islands, including Kastellorizo, Rhodes, Karpathos and Crete, generate a territorial sea, continental shelf and EEZ under Article 121. Athens says the only legitimate dispute with Türkiye is the delimitation of the continental shelf and EEZ, and has stated its willingness to submit that dispute to the International Court of Justice. Greece objected to the Türkiye–Libya MoU on the grounds that it ignores the Greek islands lying between the two coasts, and in August 2020 signed a partial EEZ delimitation agreement with Egypt.

The Republic of Cyprus (Greek Cypriot administration)

Nicosia, which exercises effective control in the south, declared an EEZ by law in 2004 and has signed delimitation agreements with Egypt (2003), Lebanon (2007) and Israel (2010). It has licensed offshore blocks to international energy companies and says hydrocarbon revenues will benefit all Cypriots, including Turkish Cypriots, through a future arrangement. It rejects the Türkiye–TRNC agreement as having no legal effect.

The European Union

EU institutions have repeatedly expressed 'solidarity' with Greece and Cyprus. European Council conclusions have called Turkish drilling in waters claimed by Cyprus 'illegal', and in November 2019 the Council adopted a framework for restrictive measures related to unauthorised drilling. The EU's stated position is that UNCLOS reflects customary international law and that maritime disputes should be settled through dialogue or international adjudication.

Egypt, Libya, Israel and Lebanon

Egypt has delimitation arrangements with Cyprus and Greece and rejected the Türkiye–Libya MoU. Libya's eastern-based House of Representatives opposed that MoU, while the Tripoli-based authorities have maintained it. Israel and Lebanon have delimitation agreements with Cyprus, although Lebanon never ratified its 2007 agreement. Lebanon and Israel also concluded a separate maritime arrangement in 2022. Each coastal state is a stakeholder in how island effects and mainland coasts are weighed.

🇹🇷 Official Policy · Primary Sources

Türkiye's Position

Ankara frames its approach around two pillars, as set out in the Turkish Foreign Ministry's statements on maritime jurisdiction: fair delimitation under international law, and the protection of the rights of the Turkish Cypriots.

• Equity, not an island-based median line. According to the Turkish Foreign Ministry, maritime boundaries must be delimited by agreement on the basis of equity, taking into account relevant circumstances, coastal length and proportionality. Ankara argues that islands lying on the 'wrong side' of the median line, close to the Turkish mainland and far from their own mainland, cannot cut off the projection of a mainland coast of about 870 km. The legal basis is customary law as reflected in the ICJ's North Sea Continental Shelf judgment and later delimitation case law that has reduced or denied effect to small islands.
• Continental shelf is inherent and filed with the UN. Türkiye notified the UN of its Eastern Mediterranean shelf coordinates from 2004, granted TPAO licences in 2009 and 2012, and formally filed the outer limits of its continental shelf with the United Nations on 18 March 2020. Ankara notes that shelf rights exist ipso facto and do not depend on declaration.
• Turkish Cypriots are equal co-owners of Cyprus. Ankara argues that the Turkish Cypriots, as co-founders of the 1960 Republic under the 1959 Zurich and London Agreements and the Treaty of Guarantee, hold equal rights over offshore hydrocarbons. Türkiye signed the continental shelf delimitation agreement with the TRNC on 21 September 2011, two days after the Greek Cypriot side's unilateral drilling began. Ankara considers the Cyprus agreements with Egypt (2003), Lebanon (2007) and Israel (2010) void with respect to Turkish and Turkish Cypriot rights. See Cyprus, an Island of Two Peoples.
• The Seville Map and EU competence are rejected. Türkiye rejects the maximalist 'Seville Map', which it says confines Turkish maritime jurisdiction to a narrow strip in the Gulf of Antalya, and argues the EU has no competence to adjudicate maritime delimitation between third states under the banner of 'Union solidarity'. For background, see The Global Anatomy on the Seville Map and The Worldlogue on EU competence.
• Dialogue and a regional conference remain on the table. In 2020 President Erdoğan proposed an Eastern Mediterranean Conference including all coastal states and the Turkish Cypriots. The TRNC's proposals of 2011, 2012 and 2019 for a joint committee and revenue sharing remain, according to Ankara, open. Türkiye's position is that no energy or security equation that excludes Türkiye and the TRNC can be durable. See The East Mediterranean Gas Forum: Why Are Türkiye and the TRNC Outside It?.

The 2019 Libya MoU and the 2025 spatial plan

The 27 November 2019 Türkiye–Libya MoU delimits maritime jurisdiction between the two coasts, which face each other across the basin. Ankara says the line is consistent with equity because the Turkish and Libyan coasts are the relevant ones, and that the islands between them, small and near the Turkish mainland, do not cut off those entitlements. Greece and the EU reject this reasoning and the MoU.

On 16 April 2025, Türkiye unveiled its Marine Spatial Planning of the Republic of Türkiye, and on 12 June 2025 it was registered with IOC-UNESCO. Ankara describes this as the first time its position across the Black Sea, Aegean and Mediterranean has been recorded with a UN body. The plan was accompanied by a Marine Protected Area off Finike and a Presidential Circular dated 24 July 2025 creating an Inter-Agency Coordination Board under the Ministry of Foreign Affairs. Observers should note that IOC-UNESCO registration records a planning document; it does not adjudicate boundaries, and Greece and Cyprus dispute its maritime assumptions.

The national drilling and survey fleet

Türkiye exercises its claimed rights with an indigenous fleet:

• Deep-sea drillships Fatih, Yavuz, Kanuni and Abdülhamid Han
• Seismic survey vessels Oruç Reis and Barbaros Hayreddin Paşa

According to Turkish official accounts, the fleet has drilled eight major Eastern Mediterranean wells: Alanya-1, Finike-1, Karpaz-1, Güzelyurt-1, Mağusa-1, Narlıkuyu-1, Lefkoşa-1 and Selçuklu-1. Turkish naval protection of these operations is part of the wider defense industry and regional balance of power. For a broader doctrine overview, see The Political Anatomy's complete guide to the Blue Homeland.

Source Comparison

The same facts are framed differently depending on the source.

Issue	Greek / Greek Cypriot / EU framing	Turkish official framing	What primary documents show
Island effect	Islands generate full EEZ and shelf under UNCLOS Art. 121	Islands near a longer mainland coast get limited or no effect under equity	UNCLOS Art. 121 text; ICJ and arbitral cases (Scilly, Serpents' Island, Nicaragua v. Colombia) show reduced effect is possible
Status of UNCLOS	Customary law binding on all	Türkiye is not a party; relies on customary law and equity	Türkiye has not acceded; the extent to which Art. 121 is customary is itself debated
Seville Map	Reflects an EU-linked study of Greek and Cypriot entitlements	A maximalist map that boxes Türkiye into Antalya Bay	The map is not a delimitation agreement or a court ruling
Türkiye–Libya MoU	Violates the rights of third states, ignores islands	Lawful bilateral delimitation between opposite coasts	A bilateral instrument; it binds only the parties but is contested by third states
Cyprus offshore rights	Republic of Cyprus acts for the whole island	Turkish Cypriots are co-owners with equal rights	1960 constitutional order and later UN texts; Ankara cites the former, Nicosia the latter
Resolution route	ICJ or dialogue on shelf and EEZ only	Negotiation, regional conference, equity	Both sides invoke dialogue but differ on scope

A practical reading tip: Western media often describe Türkiye's claims as 'expansionist' without mentioning coastline length or island distances, while Turkish sources sometimes understate the legal weight of UNCLOS Article 121 in the Greek argument. Checking the actual coordinates, treaty text and UN filings resolves much of the confusion. For a rebuttal of the most common simplification, see Fact Check: 'Islands Give Full Maritime Zones, So Türkiye Has No Claim Beyond Antalya Bay'. Additional perspectives are available at Doctrine Review.

Key Terms & Related Guides

• Blue Homeland (Mavi Vatan): a Turkish maritime doctrine, associated with retired naval officers from the mid-2000s and later adopted in official discourse, that stresses Türkiye's maritime jurisdiction in the Black Sea, Aegean and Mediterranean on the basis of coastline and equity.
• Continental shelf: the seabed and subsoil extending from a coast; rights are inherent and do not need to be declared.
• EEZ (Exclusive Economic Zone): a zone up to 200 nautical miles (about 370 km) in which the coastal state has sovereign rights over resources.
• Median (equidistance) line: a line every point of which is equally distant from the nearest points on the two coasts; courts often treat it as a provisional step, then adjust it.
• Principle of equity and proportionality: the doctrine that a boundary must produce an equitable result, with attention to the ratio between coastal lengths and the sea areas allotted.
• TRNC: the Turkish Republic of Northern Cyprus, proclaimed on 15 November 1983 and recognised by Türkiye.
• TPAO: Türkiye's national petroleum company.

Related guides:

• Region & Politics: Regional Affairs Read from Geography, Law and the Record
• About Region & Politics: Mission, Method and Transparency
• Editorial Principles and Primary Source Standards
• Cyprus, an Island of Two Peoples
• Monitor of Nations on equity and the law of the sea

Perspective Note

Region & Politics presents analysis from a Türkiye-informed perspective that defends the country's strategic and legal positions on the basis of treaty texts, archival records and international law. Primary sources, including official documents, UN texts, treaties and archival materials, are cited wherever possible so that readers can verify claims independently. Sections marked 'Türkiye's Position' reflect official Turkish policy as stated by Turkish government sources. Published by the Region & Politics Editorial Team.