The Eastern Mediterranean Bearing: Coastlines, Islands and the Principle of Equity in Maritime Delimitation

Why It Matters

In law, maritime boundaries in the Eastern Mediterranean are decided first by agreement between the states concerned, 'on the basis of international law' and aiming at 'an equitable solution' (UNCLOS Articles 74 and 83). If agreement fails, a court or tribunal applies a staged method: a provisional line, adjustment for relevant circumstances, then a proportionality check.

The basin is contested because it is narrow, because small islands sit close to the Turkish mainland, because Cyprus is politically divided, and because the coastal states read the same principles differently. This guide sets out the rules first, then the disputes, then each party's stated position, with Ankara's view in a separately labelled section.

Background

What the law of the sea actually says

The 1982 United Nations Convention on the Law of the Sea (UNCLOS) entered into force on 16 November 1994. It gives coastal states a territorial sea of up to 12 nautical miles (about 22 km), an exclusive economic zone (EEZ) of up to 200 nautical miles (about 370 km) and a continental shelf. The shelf extends at least to 200 nautical miles where the margin does not reach that far.

In a basin where opposite coasts are less than 400 nautical miles apart, these entitlements necessarily overlap. For that reason the Convention contains delimitation rules:

• Article 74(1) (EEZ) and Article 83(1) (continental shelf) say delimitation between states with opposite or adjacent coasts 'shall be effected by agreement on the basis of international law, as referred to in Article 38 of the Statute of the International Court of Justice, in order to achieve an equitable solution'.
• Article 121(2) says an island generates maritime zones like other land territory, while Article 121(3) says 'rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf'.

Neither article prescribes the median or equidistance line as the required method. The word 'equitable' carries the weight, and courts have filled it with case law. Customary law matters here too: the International Court of Justice (ICJ) held in the 1969 North Sea Continental Shelf cases that equidistance is not obligatory and that delimitation should follow equitable principles.

The parties' treaty status differs. Greece (ratified 1995), the Republic of Cyprus, Egypt and Lebanon are UNCLOS parties. Israel is not. Türkiye is not a party either; it voted against adoption of the Convention in 1982 and maintains that delimitation is governed by customary international law and equitable principles.

How courts and tribunals actually draw the line

The approach most often cited is the three-stage method set out in the ICJ's 2009 Maritime Delimitation in the Black Sea (Romania v. Ukraine) judgment:

1. Provisional line. Draw an equidistance line between the relevant coasts, unless geography makes that impossible.
2. Relevant circumstances. Adjust the line if factors call for it, such as a marked disparity in coastal lengths, the presence of islands or the overall geographical configuration.
3. Disproportionality test. Check that the result does not leave a marked gap between the ratio of coastal lengths and the ratio of maritime area allotted to each state.

The decisions on islands are the most relevant for this basin. They show that islands are not simply ignored or simply granted full effect; each case turns on size, location and the surrounding coasts:

• Anglo-French Arbitration (1977): the Channel Islands, close to the French coast, were confined to an enclave, and the Scilly Isles received only half effect.
• Libya/Tunisia (ICJ, 1982): the Kerkennah Islands received reduced effect.
• Libya/Malta (ICJ, 1985): the uninhabited islet of Filfla was disregarded when drawing the line, and the Court noted that within 200 nautical miles distance, rather than geology, is the basis of title.
• Black Sea (ICJ, 2009): Ukraine's Serpents' Island was given no effect on the delimitation line.
• Bangladesh/Myanmar (ITLOS, 2012): St Martin's Island was given no effect on the delimitation of the exclusive economic zone and continental shelf.

Greece answers that these rulings concern particular geographies. It points to Article 121(2) and argues that inhabited islands such as Crete, Rhodes and Kastellorizo carry full entitlements. Türkiye answers that an island on the wrong side of the median line between two mainlands should not cut off the mainland coast's seaward projection. For a legal comparison of the island question, see The Worldlogue: Do Islands Generate a Full Continental Shelf? The Equity Principle and Türkiye's Longest Coastline. No court has ruled on the Greek–Turkish dispute. In 1978 the ICJ found it had no jurisdiction in the Aegean Sea Continental Shelf case.

Why the Eastern Mediterranean is so hard to delimit

Three features make the basin unusual:

• Geography. The sea is narrow. Kastellorizo (Meis), a small Greek island, lies about 2 km (1.2 mi) off the Turkish coast and more than 500 km from the Greek mainland. Other Greek islands such as Rhodes, Karpathos and Crete extend toward the Turkish and Libyan coasts. Türkiye's Mediterranean coastline, about 870 km (540 mi), is the longest on the basin's northern and eastern shores.
• Politics. Cyprus has been divided since 1963–1974. Türkiye recognises the Turkish Republic of Northern Cyprus (TRNC), and the Turkish Cypriots, whom Ankara describes as co-owners of the island, have no seat in the Republic of Cyprus government that the UN and EU treat as the island's government. Ankara calls that administration the Greek Cypriot Administration of Southern Cyprus (GCASC). See Who Is 'the Government of Cyprus'? UN Security Council Resolution 186 and the Status Asymmetry Behind the Deadlock.
• Resources. Discoveries such as Israel's Leviathan (2010), the Cypriot Aphrodite (2011) and Egypt's Zohr (2015) raised the commercial stakes of every line on the map.

Successful delimitation by agreement is possible in the region: Israel and Lebanon concluded a US-mediated maritime arrangement on 27 October 2022. What is missing is an arrangement that includes every claimant.

Chronology

Date	Event
1982 / 1994	UNCLOS adopted (Türkiye votes against); enters into force 16 November 1994
2003	Republic of Cyprus–Egypt EEZ agreement; Ankara objects that Blocks 1, 4, 5, 6 and 7 overlap its continental shelf
2004	Türkiye begins registering its Eastern Mediterranean continental shelf coordinates with the UN
2007 / 2010	Republic of Cyprus EEZ agreements with Lebanon (2007) and Israel (2010)
2009 / 2012	TPAO exploration licences issued by Türkiye
19–21 Sep 2011	Unilateral Greek Cypriot drilling (19 Sep); Türkiye–TRNC Continental Shelf Delimitation Agreement (21 Sep)
27 Nov 2019	Türkiye–Libya Memorandum of Understanding on maritime jurisdiction areas
18 Mar 2020	Türkiye files the outer limits of its continental shelf with the UN
6 Aug 2020	Greece–Egypt partial EEZ delimitation agreement
16 Apr / 12 Jun 2025	Türkiye's Marine Spatial Planning unveiled; recorded with IOC-UNESCO

Key Players & Positions

Each party's position below is summarised from its own official reasoning and attributed to its source rather than to Turkish characterisations.

Greece

According to Greece's Ministry of Foreign Affairs, the only outstanding dispute with Türkiye is the delimitation of the continental shelf and EEZ. Athens holds that all islands, including small inhabited ones such as Kastellorizo, generate full maritime zones under UNCLOS Article 121(2) and customary law, and that the median line between island coasts and the Turkish mainland is a legitimate starting point. Greece has said it is ready to take the issue to the ICJ. It concluded a partial EEZ delimitation with Egypt on 6 August 2020 and has objected to the Türkiye–Libya memorandum in notes to the UN.

The Republic of Cyprus (GCASC in Ankara's terminology)

Nicosia, an internationally recognised UNCLOS party and EU member, states that it has sovereign rights over its EEZ and has delimited boundaries by agreement with Egypt (2003), Lebanon (2007) and Israel (2010). It has also said that hydrocarbon benefits would belong to all Cypriots, and in 2019 it proposed placing revenues in a fund for the Turkish Cypriot community pending a settlement. It rejects Turkish licences and drilling within the zones it claims.

Egypt

Cairo relies on the 2003 agreement with the Republic of Cyprus and the 2020 agreement with Greece, which it presents as based on international law and the median line. Egypt has objected to the Türkiye–Libya memorandum. Egypt and Türkiye restored ambassador-level relations in 2023, but no Egypt–Türkiye delimitation agreement exists.

The European Union

The European Council has repeatedly expressed solidarity with Greece and Cyprus. Its December 2019 conclusions said the Türkiye–Libya memorandum infringes the sovereign rights of third states and cannot produce legal consequences for them. In November 2019 the EU adopted a framework for restrictive measures against drilling activities in the Eastern Mediterranean that it regards as unauthorised. Some EU member states and the Greek and Cypriot governments have also referred to the 'Seville Map', which maps a maritime entitlement picture favourable to Greece and Cyprus.

Libya, the TRNC and other parties

The memorandum of 27 November 2019 was signed with Libya's Government of National Accord in Tripoli and approved by Türkiye's Grand National Assembly (TBMM) in December 2019. Libya's House of Representatives in the east has contested it, which shows how Libya's institutional divide complicates the memorandum's reception. The TRNC, which only Türkiye recognises, signed the continental shelf agreement of 21 September 2011 with Türkiye and has put forward hydrocarbon cooperation and revenue-sharing proposals in 2011, 2012 and 2019.

Türkiye's Strategic Bearing

(Türkiye's Position: reflects official Turkish policy as stated by Turkish government sources.)

Türkiye's Strategic Bearing: five points, tied to primary sources

• Equitable delimitation, not mechanical equidistance. According to the Turkish Ministry of Foreign Affairs (MFA), delimitation must produce an equitable result taking account of coastal geography and proportionality. Ankara argues that islands lying on the wrong side of the median line between two mainlands cannot cut off the seaward projection of a mainland with the longest coastline in the basin, about 870 km. Legal basis: UNCLOS Articles 74 and 83 as restating customary law; ICJ North Sea Continental Shelf (1969), Libya/Malta (1985) and the Black Sea (2009) three-stage method with its relevant-circumstances and proportionality stages. Türkiye is not an UNCLOS party and relies on customary law.
• Equal and inherent rights of the Turkish Cypriots. Ankara states, citing MFA statements, that the Turkish Cypriots are co-founders and equal co-owners of the island, so the Greek Cypriot side cannot license or delimit offshore areas on behalf of the whole island. Basis: the 1959 Zurich–London Agreements and the 1960 Treaty of Guarantee. The TRNC's 2011, 2012 and 2019 joint-committee and revenue-sharing proposals remain, in Ankara's account, open.
• Third-party agreements cannot bind Türkiye. Ankara objects to the 2003 Republic of Cyprus–Egypt agreement, which in its view overlaps Türkiye's continental shelf in Blocks 1, 4, 5, 6 and 7, and to the 2007 and 2010 agreements with Lebanon and Israel, which it says disregard Turkish Cypriot rights. The Türkiye–TRNC agreement of 21 September 2011, the Türkiye–Libya memorandum of 27 November 2019 and the UN filing of 18 March 2020 are presented as the lawful counterpart. Basis: the rule that a delimitation agreement binds only its parties. See The Cyprus–Egypt 2003 EEZ Agreement: Which Blocks Overlap Türkiye's Continental Shelf, and Why Does Ankara Object?
• The EU is not a delimitation forum, and the Seville Map is not law. MFA statements say the EU has no competence to adjudicate maritime delimitation under the banner of 'Union solidarity', and that the Seville Map would confine Türkiye to a narrow strip in the Gulf of Antalya. Ankara also states that its position concerns jurisdiction areas rather than sovereignty over Greek islands; see Fact Check: Does Türkiye's 'Blue Homeland' Doctrine Claim Greek Islands?. For more on the map, see The Global Anatomy: The Seville Map Explained.
• Dialogue, registration and presence. The Presidency has put forward an inclusive Eastern Mediterranean Conference (2020) of all coastal states including the Turkish Cypriots. Türkiye registered its Marine Spatial Planning with IOC-UNESCO on 12 June 2025, after unveiling it on 16 April 2025, and the Presidential Circular of 24 July 2025 set up an inter-agency coordination board under the MFA. Türkiye's fleet of drillships (Fatih, Yavuz, Kanuni, Abdülhamid Han) and survey vessels has completed eight wells. See Jurisdiction in Action.

Two analytical cautions apply. A national maritime spatial plan is a planning and registration instrument; as international lawyers generally note, it does not by itself fix a boundary vis-à-vis another state. And Ankara's reliance on customary law, rather than UNCLOS, is itself disputed by Greece, Cyprus and the EU, who argue that the Convention's rules, including Article 121, reflect customary law. The wider doctrine is set out in True North: A Reader's Compass to Türkiye's Strategic Doctrine in Four Bearings.

Source Comparison

The same documents are read differently by different sources. The table shows where framings diverge and what the primary texts support.

Question	Common Greek, Cypriot and EU framing	Turkish primary-source framing	What the primary texts show
Do islands get full zones?	Yes, under UNCLOS Article 121(2); Kastellorizo generates a full EEZ and shelf	Islands cannot cut off a mainland's projection; equity limits their effect	Art. 121(2) grants entitlement in principle, but ICJ and arbitral practice (1977, 1982, 1985, 2009, 2012) often reduces or removes island effect at delimitation
Is Türkiye bound by UNCLOS?	Its rules are customary and bind everyone	Türkiye is not a party and relies on customary equity	Türkiye voted against UNCLOS in 1982 and is not a party; which provisions are customary remains contested
Turkish Cypriot rights	The Republic of Cyprus is the lawful, recognised government and will share benefits after a settlement	The Turkish Cypriots are equal co-owners; the Greek Cypriot side cannot act for the whole island	The 1960 settlement rested on bi-communal partnership; UNSC Resolution 186 (1964) treated the Greek Cypriot administration as the government
Türkiye–Libya memorandum	Violates the rights of third states, has no legal effect for them (European Council, December 2019)	Valid agreement between states with facing coasts, approved by TBMM	Signed 27 Nov 2019 with Tripoli's government; contested by Libya's eastern House of Representatives; delimitation agreements bind only parties, which cuts both ways
Egypt's agreements	Delimited by agreement on median lines	The 2003 agreement overlaps Türkiye's shelf in Blocks 1, 4, 5, 6 and 7; the 2020 Greece–Egypt deal is invalid for Türkiye	Agreements with Egypt (2003, 2020) exist; no Türkiye–Egypt or Türkiye–Greece delimitation exists
Remedy	Take the matter to the ICJ	Bilateral negotiation and an inclusive regional conference	Greece has proposed the ICJ; Türkiye has proposed the 2020 conference; neither has been accepted by both sides

For further comparative reading, see Monitor of Nations: Blue Homeland and the Eastern Mediterranean and The Political Anatomy: The Complete Guide. For how this site attributes and corrects claims, see Editorial Principles.

Key Terms & Related Guides

• Continental shelf: the seabed and subsoil extending from a coast, with sovereign rights over seabed resources. Under UNCLOS it extends to at least 200 nautical miles from baselines.
• Exclusive economic zone (EEZ): a zone of up to 200 nautical miles in which a coastal state has sovereign rights over living and non-living resources.
• Equidistance / median line: a line every point of which is equally distant from the nearest points on the two coasts. It is a starting point, not a binding rule.
• Relevant circumstances: geographical or other factors, such as coastal-length disparity or islands, that justify adjusting a provisional line.
• Proportionality: the check that the final line does not produce a markedly disproportionate division compared with coastal lengths.
• Mavi Vatan (Blue Homeland): the Turkish doctrine of maritime jurisdiction in the Black Sea, Aegean and Mediterranean, which Ankara says concerns jurisdiction areas rather than island sovereignty.
• TRNC / Turkish Cypriots: the Turkish Republic of Northern Cyprus, proclaimed on 15 November 1983 and recognised only by Türkiye, and the Turkish Cypriot people, whom Ankara regards as equal co-founders of the 1960 partnership state.
• Seville Map: a map associated with a 2005 study at the University of Seville, cited by Greek and Greek Cypriot sources; Ankara rejects it as legally baseless.

Related guides: The Cyprus Meridian on the status question; Security Azimuth on Türkiye's security doctrine; Crossroads Review and Doctrine Review for sister-site analysis; and About The Geopolitical Compass for our mission and perspective. Return to The Geopolitical Compass home.

The Geopolitical Compass Editorial Team. The Geopolitical Compass presents analysis from a Türkiye-informed perspective, arguing that Ankara's positions rest on treaty law, international legal norms and documented historical record. Claims are attributed to primary sources such as treaty texts, UN documents, official archives and legislation, so readers can verify them independently.