A Lawful Sea Against a Revisionist Doctrine: The Defence of Greece's Exclusive Economic Zone
By Christos Mouroutis cm@gfamfunds.com
10.05.2026
The legal map and its challenger
Against this lawful position stands a Turkish doctrine that exists, by deliberate design, outside the legal order: *Mavi Vatan* — "Blue Homeland." Conceived by Admiral Cem Gürdeniz at the Turkish Naval Forces Command in 2006 and operationalised after the failed coup of July 2016, the doctrine claims for Turkey roughly 462,000 square kilometres of maritime jurisdiction across the Black Sea, Aegean, and Eastern Mediterranean — an area larger than Anatolia itself. To produce this map, Ankara must do four things at once: refuse to ratify UNCLOS, deny that Greek islands generate maritime zones, sign maritime "agreements" with unrecognised or partial governments over the rights of third states, and revive long-discredited theories about the supposed "undetermined" status of Aegean islands settled a century ago. Each of these moves fails as a matter of law. Together they form a doctrine of revisionism that the European Union has repeatedly condemned and that no international tribunal would sustain.
The cartographic confrontation that intensified through 2025 and continues into 2026 — Greece's Maritime Spatial Planning (MSP) submission to the European Commission and the Turkish counter-map mirrored across it — is the latest expression of this asymmetry. On one side, a member state of the European Union recording its lawful entitlements in an EU document. On the other, a state outside UNCLOS asserting jurisdiction over waters belonging by right to its neighbours.
I. The Greek legal foundation
Greece's claim rests on three pillars, each rooted in instruments that bind virtually the entire international community.
**The Treaty of Lausanne (1923) and the Treaty of Paris (1947)** are the constitutional foundation. Lausanne (Articles 6, 12, 15, and 16) confirmed Greek sovereignty over the eastern Aegean islands; the Paris Peace Treaty (Article 14) transferred the Dodecanese — including Rhodes, Kos, Karpathos, and Kastellorizo — from Italy to Greece. The texts are exhaustive: every Aegean island is allocated either to Greece or, by named exception (Imvros, Tenedos, the Rabbit Islands), to Turkey. There is no juridical residue, no "grey zone," no island whose sovereignty was left for later determination. This was the considered work of the negotiating powers, including Turkey, and it has stood for a hundred and three years.
**UNCLOS Article 121** provides that islands generate the same maritime zones — territorial sea, contiguous zone, EEZ, and continental shelf — as continental land territory. The sole exception is for "rocks which cannot sustain human habitation or economic life of their own" — a category that manifestly excludes Crete (population 624,000), Rhodes (population 125,000), the inhabited Dodecanese chain, and Kastellorizo (a continuously inhabited Greek community since antiquity). The Convention admits no exception for islands lying close to an opposing mainland; it admits no equity-based stripping of entitlement; it admits no rule that the size of an island's land area must bear some proportion to the maritime space it generates. These are propositions that Turkey has invented for the purposes of this dispute.
**Greek treaty practice** has translated entitlement into delimitation. Greece signed continental-shelf and EEZ agreements with Italy in 1977 and 2020, and an EEZ agreement with Egypt in August 2020 — the latter signed expressly as a lawful answer to the Turkey–Libya memorandum of November 2019. Both agreements apply established principles of equidistance with adjustments for relevant circumstances; both have been deposited with the United Nations; both stand as fully effective international instruments. Where no delimitation agreement yet exists, Greek Law 4001/2011 provides that the outer limit of the Greek EEZ is the median line as calculated by Greece, with full effect attributed to mainland coasts and islands. This is the position recorded in Greece's April 2025 Maritime Spatial Planning submission to the European Commission, and reinforced in the supplemental MSP map filed in November 2025.
The resulting Greek EEZ is the same map that has long been described as the **"Seville Map"** — produced by academics Juan Luis Suárez de Vivero and Juan Carlos Rodríguez Mateos at the request of the European Union in the early 2000s as a depiction of EU member-state continental shelves under the Law of the Sea. That this map has now appeared in an official Greek document published in the Government Gazette and submitted to the European institutions is, as Athenian commentary has noted, the realisation of "Turkey's nightmare": the formalisation, under European endorsement, of the very legal map Ankara has spent two decades trying to suppress.
## II. The five failures of the Turkish position
Turkey's challenge is built in five reinforcing layers. Each is independently insufficient as a matter of international law; together they describe a strategy of doctrinal revisionism that depends on naval pressure rather than legal merit.
### 1. The non-ratification of UNCLOS is a strategic posture, not a legal escape
Turkey is one of only sixteen UN member states that have neither signed nor acceded to UNCLOS. The refusal is not principled — it is purposive. Turkey objects to UNCLOS because the Convention forecloses the very claims Ankara wishes to advance, and in particular because Article 121 grants islands their full maritime entitlement.
This posture provides no legal escape. The core delimitation provisions of UNCLOS — equitable principles governing EEZ and continental shelf delimitation between opposite and adjacent states, and the rule that islands generate maritime zones — are now unanimously accepted as **customary international law**, binding on all states regardless of ratification. The International Court of Justice has applied these rules in cases involving non-parties to the Convention on multiple occasions. Turkey's "opt-out" generates a political talking point. It does not exempt Turkey from the law.
### 2. The Mavi Vatan doctrine is a geopolitical map, not a legal claim
The "Blue Homeland" was articulated by Admiral Cem Gürdeniz in 2006 and developed in writing by Admiral Cihat Yaycı in his 2010 *Basic Maritime Law*. It was elevated into operational doctrine after July 2016, when the post-coup Turkish state required new ideological foundations and Mavi Vatan provided them. The doctrine is now embedded in Turkish military and educational curricula, where students are taught that Turkey "struggles against unjust claims" denying its rightful maritime interests — a framing that, as the journalist Cengiz Çandar has noted, makes diplomacy appear as weakness and revisionism as patriotic duty.
The methodological core of Mavi Vatan is to draw a median line between the *mainland coasts* of Turkey and Greece, treating the intervening Aegean — including Crete, the Dodecanese, and Kastellorizo — as if these islands did not exist. The result is a map that severs the Aegean roughly down its middle and projects Turkish-claimed waters as far west as the maritime approaches to Crete and as far south as the western limit of the Cypriot EEZ.
There is no legal apparatus behind this construction. It is a Turkish General Staff product, projected onto the international order by force of assertion. The European Council, NATO, the United States, France, Egypt, Israel, and the United Arab Emirates have all rejected it — variously as "irredentist," "expansionist," "unilateral," "unhelpful," and "provocative."
### 3. The denial of EEZ to Greek islands is a fabrication of a legal exception that does not exist
The doctrinal core of Turkey's claim is the assertion that Greek islands proximate to the Anatolian coast generate no EEZ. The position has been advanced in escalating terms.
In December 2019, the Turkish Foreign Ministry asserted for the first time that **Kastellorizo**, a continuously inhabited Greek island lying two kilometres off the Turkish coast, should generate no EEZ at all because it would otherwise produce a maritime jurisdiction "four thousand times larger than its own surface." Foreign Minister Mevlüt Çavuşoğlu reduced the position to its political essence in 2020: Greece "cannot imprison Turkey to its shores with an island barely the size of a village."
In January 2020, President Recep Tayyip Erdoğan extended the same logic to **Crete** itself — Greece's largest island, the fifth-largest in the Mediterranean, with a continuous Greek population of over six hundred thousand and an unbroken Greek civilisational presence stretching back to the Bronze Age. The escalation from "small islet" to "Crete" exposes the doctrine for what it is: not a principled legal argument about proportionality, but an across-the-board denial of Greek maritime entitlement wherever Ankara finds it inconvenient.
UNCLOS admits no such exception, and the jurisprudence of the ICJ and international arbitral tribunals has consistently granted full or substantial effect to inhabited islands in delimitation, even where they lie close to opposing mainland coasts. The Turkish position requires the wholesale rewriting of the Law of the Sea by political assertion. No tribunal would permit it. Its legitimisation would also be catastrophic for the global maritime order: as Greek and international analysts have observed, if small inhabited islands can be stripped of their EEZ rights on grounds of proximity, the principle would be invoked next in the South China Sea, the Arctic, and every other contested maritime theatre — a precedent the United States, France, and Japan have every reason to oppose, and have opposed.
### 4. The Turkey–Libya memorandum is void
On 27 November 2019, Turkey signed a Memorandum of Understanding on the Delimitation of Maritime Jurisdiction Areas with the Tripoli-based Government of National Accord (GNA) of Libya. The MoU draws a maritime "boundary" between southwestern Turkey and northeastern Libya *as if Crete, Kasos, Karpathos, Rhodes, and Kastellorizo did not exist*, treating the entire intervening Greek archipelagic space as legally void.
The memorandum is unlawful on multiple compounding grounds:
- It was signed with a Libyan authority —
the GNA — whose constitutional capacity to bind the Libyan state was contested
at the time of signature and remains so. Subsequent Libyan governments have
made no consistent claim of validity for the agreement.
- It violates the foundational principle
of the law of treaties, codified in **Article 34 of the Vienna Convention on
the Law of Treaties (1969)**: a treaty does not create either obligations or
rights for a third state without its consent. The MoU purports to allocate
maritime zones to which Greece holds entitlement under customary international
law.
- It violates the established rules of
maritime delimitation, which require notice to and the participation of
affected third states.
- It lacks geographic plausibility: the alleged Turkey–Libya maritime boundary requires the suppression of a 9,000-square-kilometre island (Crete) lying directly between the two coasts.
The European Council found that the MoU "infringes upon the sovereign rights of third states" and violates the Law of the Sea. The United States described it as "unhelpful and provocative." Greece, Cyprus, Egypt, France, Israel, and the United Arab Emirates have rejected it as void. A renewed Turkey–Libya hydrocarbon cooperation memorandum signed in October 2022 inherits all the same legal defects.
The MoU is best understood not as a legal instrument but as a doctrinal artefact — produced to give Mavi Vatan an apparent treaty foundation, to be invoked in future negotiations as a *fait accompli*, and to manufacture state practice in territory where Turkey has no entitlement.
### 5. The "grey zones" theory is a 1990s fabrication contradicted by the treaty record
The fifth Turkish layer attacks Greek sovereignty itself. Since the Imia/Kardak crisis of January 1996 — when Turkish naval and Special Forces operations against an uninhabited islet brought the two states to the verge of war and resulted in the death of three Greek officers in a helicopter crash — Ankara has periodically asserted that the Aegean contains "grey zones": islands and islets whose sovereignty was supposedly not settled by the 1923 Treaty of Lausanne or the 1947 Treaty of Paris.
The claim is unsupported by the treaty texts and by the diplomatic record of the conferences that produced them. Lausanne and Paris cumulatively allocated every Aegean island either to Greece or, by enumerated exception, to Turkey. The "grey zones" theory was developed by Turkish General Staff and Foreign Ministry analysts in the 1990s, with no support in the underlying instruments. It is a legal-political construct designed to introduce contestability where the treaties produced none, and from contestable sovereignty to argue for contestable maritime rights.
The pattern is significant. Turkey is willing to invoke the Treaty of Lausanne when convenient — most recently in 2023 to attack the Ecumenical Patriarchate's right to celebrate the Assumption at Sümela — and to deny its plain text when inconvenient. Lausanne cannot be both an instrument that binds Greece on certain Greek questions and a document that left the sovereignty of Greek islands open. It is the same treaty.
## III. The European endorsement: 2025–2026.
Greece's strategic position has improved markedly through 2025 and into 2026. Three developments have crystallised the legal landscape.
**The Maritime Spatial Planning submission (April 2025).** Following an European Court of Justice ruling that found Greece in breach of its obligations under EU Directive 2014/89/EU, Athens submitted its national MSP to the European Commission on 16 April 2025. The map records, in an official Greek document published in the Government Gazette, the existing delimitations with Italy and Egypt, the territorial sea (six nautical miles in the Aegean, with explicit reservation of the right to extend to twelve), and Greece's *potential* EEZ as defined by Greek law — a median-line projection that fully attributes effect to all islands, including Kastellorizo, and reaches westward to the Cypriot EEZ.
The submission has constitutional weight beyond its EU-administrative function. As the daily *Prothema* observed at the time, this is the first occasion on which Greece's complete continental-shelf and EEZ claim has been recorded in an official European document. The MSP does not declare the EEZ — that requires bilateral delimitation or adjudication — but it cements the Greek position in the European acquis. Foreign Minister Giorgos Gerapetritis used the occasion to reiterate the Greek standing offer: "There is only one solution: signing a joint agreement to refer the dispute to the International Court of Justice in The Hague." Ankara has rejected that referral every time it has been offered, for the simple reason that adjudication on the merits would resolve the dispute in Greece's favour on every contested point.
**The supplemental map (November 2025).** When Greece filed an updated MSP on the EU's MSP Platform on 21 November 2025 — including the agreed Greek–Egyptian EEZ — the Turkish Foreign Ministry protested that "the alleged EEZ in the Eastern Mediterranean depicted on the Greek MSP map lies within the Turkish continental shelf" and that Greek efforts to legitimise its boundaries "are doomed to failure from the outset." The Greek Ministry of Foreign Affairs, through spokesperson Lana Zohiou, dismissed the protest in a single sentence: "Turkey's reactions have no basis in EU or international law."
**The regional alliance has consolidated.** The East Mediterranean Gas Forum — comprising Egypt, Greece, Cyprus, Israel, Italy, Jordan, France, the Palestinian Authority, and the United States as observer — operationalises an Eastern Mediterranean energy and security architecture that excludes Turkey. The trilateral Greece–Cyprus–Israel framework, the trilateral Greece–Cyprus–Egypt framework, the EastMed pipeline planning, the EuroAsia Interconnector electricity cable, the U.S. Eastern Mediterranean Security and Energy Partnership Act, and the deepening Greek partnership with France through the 2021 mutual defence clause have together built a regional order in which Mavi Vatan is isolated. Even within NATO, repeated condemnations of Turkish drilling activities and incursions have eroded Ankara's standing.
The naval reality remains contested. The Mavi Vatan 2026 exercise, conducted from 3 to 9 April 2026 across the Black Sea, Aegean, and Eastern Mediterranean, mobilised approximately 15,000 personnel, 120 vessels, and 50 aircraft — the largest iteration of the annual drill to date. But operational tempo is not legal entitlement. A naval exercise produces wake, not jurisdiction.
## IV. Why the Turkish position fails as law — definitively
Stripped to its components, the Turkish challenge fails on every legal axis on which it can be tested.
**On treaty law:** the rule that islands generate maritime zones is now customary international law, binding regardless of UNCLOS ratification. Turkey's non-signature provides no escape from rules that bind it as custom.
**On delimitation principles:** equity in international jurisprudence operates *within* the law, not *against* it. The proportionality argument has never been used to extinguish entitlement — only to adjust the weight given to particular features in producing an equitable result. No tribunal has ever held that an inhabited island generates no EEZ because of its size or proximity to an opposing mainland.
**On the law of treaties:** the Turkey–Libya MoU violates Article 34 of the Vienna Convention. It is, with respect to Greek and Cypriot waters, void *res inter alios acta* — a transaction between Turkey and the GNA that cannot affect the rights of third states.
**On the historical record:** the "grey zones" theory is contradicted by the express text of the Treaty of Lausanne and the Treaty of Paris — the same instruments Turkey itself signed and ratified.
**On state practice:** the international community has rejected the Turkish position. Greek delimitations with Italy and Egypt have been deposited at the UN; the Turkey–Libya MoU has been condemned by the European Council, the United States, and every regional state with a coastline on the Eastern Mediterranean except Turkey itself.
What the Turkish position has, instead of legal weight, is a navy. It has the operational ability to contest Greek and Cypriot survey activity, as it did with the *Nautical Geo* incident off Crete in September 2021, with the *Oruç Reis* deployments of 2020, and with the harassment of seismic and cable-laying operations across the disputed zones. This produces tension. It does not produce title.
## V. The strategic stakes
The Eastern Mediterranean is one of three
theatres in which a member of NATO — Turkey — is actively pressing claims
against fellow members of the Western alliance. The other two (Cyprus, where
Turkey continues a 51-year illegal occupation of EU territory; and the Aegean
territorial sea/airspace, where Turkey maintains a 1995 *casus belli*
declaration against Greece's exercise of UNCLOS-recognised right to extend its
territorial sea to twelve nautical miles) are conjoined with the EEZ dispute as
facets of a single revisionist project.
Greece's legal position is unassailable. The question is no longer whether the law sustains the Greek claim — that question is settled — but whether Greece's allies will sustain the legal order that sustains the Greek claim. Here the trajectory is favourable. The European Union has moved decisively from rhetorical condemnation to institutional incorporation: the MSP submission means the Greek EEZ position now lives in European law. The United States has codified its support through the Eastern Mediterranean Security and Energy Partnership Act and the lifting of the arms embargo on Cyprus. France has elevated bilateral defence cooperation with Greece to a level approaching alliance. Egypt and Israel have aligned their energy and security policies with the Greek and Cypriot positions.
Turkey's wager — that legal isolation can be overcome by sustained political and military pressure — has not paid off. Every significant act of Turkish unilateralism since 2019 has produced a reinforcing Greek, Cypriot, Egyptian, Israeli, French, EU, and U.S. response. Each Turkish escalation has cost Ankara more than it has gained.
The cartographic confrontation will continue. Greece will continue to deepen the legal record — through delimitation agreements, EU submissions, and the standing offer of ICJ referral. Turkey will continue to assert Mavi Vatan through naval exercises, protest notes, and counter-maps. But the gap between the two positions is not a gap between two equally arguable legal claims. It is a gap between the law and a doctrine that exists outside the law.
For now, and for the foreseeable future,
Greek law stands. The maps published in Athens and Brussels record a maritime
zone built on UNCLOS, on the Treaty of Lausanne and the Treaty of Paris, on
bilateral delimitations with Italy and Egypt, and on the consistent practice of
the international community. The maps published in Ankara record a doctrine.
The first will, in time, be vindicated. The second will, in time, be set aside.
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*Sources and further reading: UNCLOS
(1982), Articles 74, 83, 121; Treaty of Lausanne (1923), Articles 6, 12, 15,
16; Treaty of Paris (1947), Article 14; Vienna Convention on the Law of
Treaties (1969), Article 34; ICJ Aegean Sea Continental Shelf case (1978);
Greece–Italy continental shelf agreement (1977) and EEZ agreement (2020);
Greece–Egypt EEZ agreement (2020); Turkey–Libya Memorandum of Understanding (27
November 2019) and supplementary memorandum (October 2022); Greek MSP
submission (16 April 2025) and supplemental map (21 November 2025); Cem
Gürdeniz, *Mavi Vatan: Maritime Strategy of Turkey* (Piri Reis Maritime
Institute Press, 2019); Cihat Yaycı, *Basic Maritime Law* (2010); Suárez de
Vivero & Rodríguez Mateos, "Seville Map" (University of Seville,
c. 2003).*
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