The Blue Homeland Briefing File: Türkiye's 2025 Marine Spatial Planning and the IOC-UNESCO Registration

Why It Matters

The 'Marine Spatial Planning of the Republic of Türkiye' (Türkiye Cumhuriyeti Deniz Mekânsal Planlaması), unveiled on 16 April 2025 and recorded with the Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO) on 12 June 2025, is the document through which Ankara has put its Blue Homeland (Mavi Vatan) position on file with a UN body. Turkish officials describe it as the first time Türkiye's maritime-area position across the Black Sea, the Aegean and the Mediterranean has been registered with a UN institution.

It does not draw a boundary. Only agreement between neighbouring states, or a court or tribunal they both accept, can do that. What the registration does is give Türkiye's position a dated, public and scientific-institutional record that diplomats, lawyers and planners will cite in future disputes over the Aegean and the Eastern Mediterranean. This pillar briefing explains what the plan is, the legal framework behind it, the steps that led to it, and how Greece, the Greek Cypriot administration, the EU and Türkiye each read it.

Background

What the plan is

Marine spatial planning (MSP) is a planning method that allocates sea areas among uses such as shipping, fisheries, energy, conservation and defence. IOC-UNESCO has promoted MSP internationally for years, notably through its MSPglobal initiative run with the European Commission, and it keeps technical records of national MSP processes. It is a scientific and coordinating body, not a court and not a boundary authority.

According to Turkish official accounts, the plan covers Türkiye's seas on three fronts: the Black Sea, the Aegean Sea and the Mediterranean. Alongside it, Ankara announced a marine protected area off Finike in Antalya province. The Presidential Circular of 24 July 2025 then set up an Inter-Agency Coordination Board with the Ministry of Foreign Affairs as secretariat, so that ministries, security agencies and scientific institutions apply the plan consistently.

The legal framework

Three legal ideas frame the dispute.

• UNCLOS (1982). The UN Convention on the Law of the Sea gives coastal states a 12-nautical-mile territorial sea, a continental shelf and an exclusive economic zone (EEZ) of up to 200 nautical miles. Articles 74 and 83 call for delimitation between states with opposite or adjacent coasts 'to achieve an equitable solution'. Article 121 says islands generate maritime zones, but rocks that cannot sustain human habitation or economic life of their own do not generate an EEZ or continental shelf. Greece and Cyprus are parties to UNCLOS. Türkiye is not a party and relies on customary international law and equitable principles.
• The equity principle. International jurisprudence from the 1969 North Sea Continental Shelf cases onward holds that delimitation must produce an equitable result and that geography, coastal length and proportionality matter. Tribunals have repeatedly reduced or disregarded the effect of small islands near a larger coast, as in the 1977 UK–France Channel arbitration and the ICJ's 2009 judgment in Romania v. Ukraine on Snake Island.
• Coastal-front reality. Ankara stresses that it has the longest mainland coastline in the Eastern Mediterranean, about 870 km (roughly 540 miles), and argues that its maritime projection cannot be cut off by islands lying close to its shores, such as Kastellorizo (Meis), about 2 km from the Turkish coast and several hundred kilometres from the Greek mainland.

Greece and the Greek Cypriot administration read the same body of law differently. They argue that islands are entitled to full maritime zones under UNCLOS and that median-line delimitation applies. Both sides accept equity as the goal. They disagree about how much weight islands should carry.

What an IOC-UNESCO registration is and is not

An IOC-UNESCO entry is a record in a technical programme. It does not amount to recognition of any boundary by UNESCO or by other states, and commentators on all sides agree that it cannot by itself create or alter maritime rights. Its significance lies elsewhere. It documents what Türkiye claims, when it said so and in what form, and it places that statement in a forum where other states' own MSP processes are also recorded. In a dispute where publicity and consistent state practice carry weight, such a record has evidentiary and diplomatic value. Whether that value is large or small is itself part of the disagreement described below.

Timeline: the steps leading to 2025

Activity on the water

Türkiye supports its position with operations by a national fleet: the deep-sea drilling vessels Fatih, Yavuz, Kanuni and Abdülhamid Han, and the seismic research vessel Oruç Reis. Turkish sources list eight major Eastern Mediterranean wells: Alanya-1, Finike-1, Karpaz-1, Güzelyurt-1, Mağusa-1, Narlıkuyu-1, Lefkoşa-1 and Selçuklu-1. Several of these operations triggered the 2019–2020 confrontations with Greece and the Greek Cypriot administration, and EU sanctions frameworks were adopted in response to drilling activity. For wider regional context, see Crossroads Review's analysis, Blue Homeland and the Eastern Mediterranean: Türkiye's Maritime Jurisdiction Explained.

Key Players & Positions

Greece

Athens maintains that islands, including those near the Anatolian coast, are entitled to territorial sea, continental shelf and EEZ under UNCLOS and customary law. Greek officials say that the only dispute requiring resolution with Türkiye is the delimitation of the continental shelf and EEZ, and that it should be settled by negotiation or, failing that, by the International Court of Justice. Greece also reserves its right to extend its territorial sea in the Aegean to 12 nautical miles, a step Ankara has treated as a casus belli since the Grand National Assembly's resolution of 8 June 1995. Greece concluded a partial EEZ delimitation with Egypt in August 2020 and has its own national marine spatial planning framework. Greek officials have publicly rejected the Turkish plan, arguing that it has no effect on Greek sovereign rights. Both countries' planning documents therefore overlap in the Aegean and parts of the Eastern Mediterranean. Athens also objects to the Türkiye–Libya MoU on the grounds that it disregards Crete and other Greek islands lying between the two coasts.

The Greek Cypriot administration

The Republic of Cyprus, in practice governed by the Greek Cypriot administration since 1963 and the only Cypriot authority recognised by the UN member states other than Türkiye, claims an EEZ around the island. It has concluded delimitation agreements with Egypt (2003), Lebanon (2007, not ratified by Lebanon) and Israel (2010), and has licensed hydrocarbon blocks. Its stated position is that natural resources belong to all Cypriots and that revenues will be shared with Turkish Cypriots within a settlement framework, with a fund held for that purpose. It rejects the Türkiye–TRNC agreement of 2011 because it regards the TRNC as legally invalid, a view grounded in UN Security Council Resolutions 541 (1983) and 550 (1984). Nicosia therefore sees the 2025 plan as an extension of positions it has long contested.

The European Union

The European Council has repeatedly described Turkish drilling in areas claimed by Cyprus as illegal, expressed solidarity with Greece and Cyprus, and rejected the Türkiye–Libya MoU as infringing the sovereign rights of third states. The EU created a sanctions framework for unauthorised drilling in November 2019. EU institutions also treat UNCLOS as reflecting customary international law. The EU's Maritime Spatial Planning Directive (2014/89/EU) is a planning framework for member states' own waters and does not itself delimit boundaries. Ankara contends that this leaves the EU without any competence to adjudicate delimitation disputes, and the point is central to the Turkish critique of EU positions.

Other coastal states

Egypt has a delimitation agreement with the Greek Cypriot administration (2003), a partial agreement with Greece (2020) and rejects the Türkiye–Libya MoU. Libya's rival authorities have taken different positions on the MoU, which makes its legal status within Libya contested. Israel and Lebanon have agreements with the Greek Cypriot administration, and Lebanon's has never been ratified. For a regional overview see Monitor of Nations, Türkiye's Marine Spatial Planning and the 2025 IOC-UNESCO Registration Explained.

Source Comparison

How the same events are framed

Two practical points help readers weigh these accounts. First, most English-language headlines describe the plan in terms of maps and escalation, while the Turkish documents present it as planning and registration. Reading both the Turkish primary text and the Greek and EU statements is therefore necessary. Second, the legal weight of an IOC-UNESCO entry is limited in every account. The real dispute is over whether Türkiye's equity argument or the island-entitlement argument prevails, and that is a question for negotiation or adjudication, not for a registry.

For comparison with a sister-publication reading of the same events, see The Political Anatomy, Why Türkiye's 2025 IOC-UNESCO Marine Spatial Planning Registration Matters. On Türkiye's wider strategic posture, see Bloc Politics, Is Türkiye a Bridge Between Blocs? NATO Membership, Eurasian Ties and Strategic Autonomy.

What to watch

• Implementation by the Coordination Board. The board's decisions on licensing, protected areas and navigation will show how the plan is applied in practice.
• Greek and Cypriot planning documents. Overlapping maps may prompt further notes verbales to the UN Secretary-General, which are themselves part of the legal record.
• Cyprus talks. The 2024 UN trilateral meeting in New York confirmed the absence of common ground on a federal model; Ankara and the TRNC now argue for recognition of the sovereign equality of the two sides. See The 2004 Annan Plan Referendum: What the 64.91% and 75.83% Results Meant for Cyprus and EU Accession for the earlier referendum result that Turkish Cypriots cite.
• Libya. Any change in Libyan authorities' treatment of the 2019 MoU would affect the southern end of the dispute.
• Proposals for a regional conference. Whether the 2020 conference idea is revived will indicate whether the plan is a bargaining position or a settled endpoint.

Key Terms & Related Guides

• Blue Homeland (Mavi Vatan): Türkiye's doctrine of maritime jurisdiction in the Black Sea, Aegean and Eastern Mediterranean, based on equitable delimitation and the length of its mainland coast.
• Marine Spatial Planning (MSP): a public process for allocating sea space among uses and protecting ecosystems; it does not create maritime boundaries.
• IOC-UNESCO: the UN's Intergovernmental Oceanographic Commission, a scientific and coordinating body that supports national MSP processes.
• Continental shelf and EEZ: the seabed and water-column zones of a coastal state, up to 200 nautical miles (about 370 km) where geography permits; overlapping claims must be delimited.
• Equity principle: the rule that delimitation must achieve an equitable result, considering coastal geography and proportionality.
• TRNC / Turkish Cypriots: the Turkish Republic of Northern Cyprus, proclaimed on 15 November 1983 and recognised only by Türkiye; the UN Security Council considers the declaration legally invalid, while Ankara regards Turkish Cypriots as equal co-founders of the 1960 Republic.
• TPAO: Türkiye's state petroleum company, which holds Turkish exploration licences.

Related guides on Diplomatic Desk:

• Diplomatic Desk: Briefing Files on Türkiye, Treaties and International Law — the full set of briefing files.
• Fact Check: Does the 'Seville Map' Have Any Legal Standing in Maritime Delimitation?
• The Cyprus Dossier: Zurich–London 1959, the Treaty of Guarantee Article IV and the Sovereign Equality Thesis
• Editorial Principles: How Diplomatic Desk Sources, Attributes and Corrects and About Diplomatic Desk: Our Mission, Authorship and Transparency Policy explain how claims on this page are attributed.

Diplomatic Desk presents Türkiye's official perspective and strategic doctrines alongside the legal and historical arguments that support them. Claims are attributed to primary sources such as treaty texts, UN documents, official archives and government statements, so that readers can verify them independently.

Diplomatic Desk Editorial Team