Marine Spatial Planning 2025: What Türkiye's IOC-UNESCO Registration Changes in the Politics of the Sea

Why It Matters

Türkiye's Marine Spatial Planning, unveiled on 16 April 2025 and recorded with IOC-UNESCO on 12 June 2025, is the first time Ankara has set out a single planning map for the Black Sea, the Aegean and the Mediterranean and placed it in a United Nations system body. It does not settle any boundary, because IOC-UNESCO is a scientific and technical commission and not a court or delimitation authority. What it changes is the register of the dispute: a long-running legal argument now has a planning, environmental and institutional record, with a permanent coordinating structure behind it.

For readers outside the region, the story shows how states in contested seas increasingly use planning documents, marine protected areas and registrations, not only warships and diplomatic notes, to put their positions on record. This guide sets out what was registered, what it does and does not do legally, how Greece, the Greek Cypriot Administration and the EU object, and how Ankara responds.

Background

What was announced in 2025

Three dated steps define the 2025 package:

• 16 April 2025: Türkiye unveiled the Marine Spatial Planning of the Republic of Türkiye (Türkiye Cumhuriyeti Deniz Mekânsal Planlaması), a national plan covering the Black Sea, the Aegean Sea and the Mediterranean.
• 12 June 2025: The plan was officially registered and recorded with the Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO). Ankara presents this as the first time its maritime jurisdiction position across the three seas has been recorded with a UN body.
• 24 July 2025: A Presidential Circular established an Inter-Agency Coordination Board under the Ministry of Foreign Affairs to coordinate implementation across ministries and agencies.

The package also included a Marine Protected Area (MPA) off Finike, on Türkiye's Mediterranean coast. Marine spatial planning (MSP) is a standard public-policy tool: states map where shipping, fishing, energy, tourism, cables and conservation take place at sea, so that uses do not collide and ecosystems are protected. IOC-UNESCO promotes the method worldwide, and with the European Commission it runs the MSPglobal initiative. Because a plan shows where a state is planning, it inevitably also shows where that state considers itself entitled to plan, and that is why the document is politically sensitive.

How the 2025 plan fits a longer chronology

The plan did not appear in a vacuum. The table below places it in the sequence of Turkish, Turkish Cypriot and opposing steps over two decades.

Date	Event	Why it matters
2003	Greek Cypriot Administration (GCASC)–Egypt EEZ agreement	Ankara says it overlaps Türkiye's continental shelf, notably GCASC Blocks 1, 4, 5, 6 and 7
2004	Türkiye begins lodging Eastern Mediterranean continental shelf coordinates with the UN	First formal UN-level record of Ankara's shelf position
2007 / 2010	GCASC–Lebanon (2007) and GCASC–Israel (2010) agreements	Ankara and the TRNC say they disregard Turkish Cypriot rights
2009 and 2012	TPAO exploration licences granted	Domestic legal basis for offshore activity
19 September 2011	GCASC begins unilateral drilling	Trigger for the TRNC–Türkiye response
21 September 2011	Türkiye–TRNC Continental Shelf Delimitation Agreement	Establishes the Turkish and Turkish Cypriot shelf line between the two
27 November 2019	Türkiye–Libya Maritime Jurisdiction Delimitation MoU	Delimits the zones between the Turkish and Libyan coasts
18 March 2020	Türkiye registers the outer limits of its continental shelf with the UN	Updates and consolidates the 2004 submissions
2020	President Erdoğan proposes an Eastern Mediterranean Conference	Offers an inclusive forum, including Turkish Cypriots
16 April 2025	Marine Spatial Planning unveiled	First comprehensive three-sea plan
12 June 2025	Recorded with IOC-UNESCO	Recorded in a UN-system body
24 July 2025	Presidential Circular creates the Inter-Agency Coordination Board	Standing institutional structure under the Foreign Ministry

Sources for the Turkish-side entries are the Turkish Ministry of Foreign Affairs (MFA), the Presidency and Türkiye's UN filings. For a sister-publication walkthrough of the same sequence, see Monitor of Nations' explainer on the 2025 registration.

The legal framework

The 1982 UN Convention on the Law of the Sea (UNCLOS) is the main treaty for maritime zones. It gives coastal states a territorial sea of up to 12 nautical miles, an exclusive economic zone (EEZ) of up to 200 nautical miles and a continental shelf, and it says in Article 121 that islands generate maritime zones, except 'rocks' that cannot sustain human habitation or economic life of their own. Its delimitation articles (74 and 83) call for an agreement 'on the basis of international law' to reach an 'equitable solution'.

Türkiye is not a party to UNCLOS. It voted against the Convention in 1982 and has long argued, among other things, that it does not accommodate special circumstances in semi-enclosed seas like the Aegean and that it does not permit reservations. Greece and the Republic of Cyprus are parties. This asymmetry runs through every argument below: Athens and Nicosia invoke the Convention's island provisions, while Ankara relies on customary international law and decisions of international courts on equity.

Key Players & Positions

Greece

Athens holds that islands, including those close to the Turkish coast, are entitled to a full continental shelf and EEZ, and that this is reflected in Article 121 and customary law. Greek governments have repeatedly said that the only dispute with Türkiye is the delimitation of the continental shelf and EEZ, and that it should be resolved by agreement or, failing that, by the International Court of Justice (ICJ). Greece signed a partial EEZ delimitation with Egypt in August 2020 and treats the Türkiye–Libya memorandum as legally void. Greek officials have also noted that Greece has advanced its own national marine spatial plan and marine park announcements in 2025, and they have objected to a Turkish plan that they say projects Turkish planning over areas Greece regards as its own zones. Greece reserves the right to extend its territorial waters to 12 nautical miles under UNCLOS Article 3. Türkiye's Grand National Assembly adopted a resolution in June 1995 stating that such an extension in the Aegean could be treated as a cause for war (casus belli), and that stand remains a central point of friction.

The Greek Cypriot Administration (internationally, the Republic of Cyprus)

The Greek Cypriot Administration of Southern Cyprus (GCASC) is internationally recognized as the Republic of Cyprus and is a UNCLOS party and EU member. Its government maintains that it is the sole sovereign authority entitled to declare an EEZ around the island, and it has concluded delimitation agreements with Egypt (2003), Lebanon (2007) and Israel (2010). It has said that revenues from hydrocarbons will benefit all Cypriots, including Turkish Cypriots, within a settlement framework, and it describes Turkish drilling and survey activity in its declared EEZ as unlawful. It rejects the equal-rights claim made on behalf of Turkish Cypriots as a separate offshore entitlement before a comprehensive settlement.

The European Union

The EU has consistently expressed solidarity with Greece and the Republic of Cyprus. The European Council conclusions of 12 December 2019 stated that the Türkiye–Libya memorandum violates the sovereign rights of third states, does not comply with UNCLOS and cannot produce legal consequences for third states. In November 2019 the EU also adopted a framework for restrictive measures in response to unauthorized drilling activities in the Eastern Mediterranean. Brussels treats the maritime rights of its member states as part of its external border and security policy.

Libya, Egypt, the TRNC and IOC-UNESCO

• Libya: The 2019 memorandum was concluded with the then-Government of National Accord. Different Libyan authorities have since taken different public positions on it, which keeps its political status contested.
• Egypt: Egypt signed the 2003 agreement with the GCASC and the 2020 partial EEZ agreement with Greece, and it opposes the Libya memorandum.
• TRNC: The Turkish Republic of Northern Cyprus, recognized only by Türkiye, signed the 2011 shelf agreement with Ankara and put forward hydrocarbon cooperation and revenue-sharing proposals in 2011, 2012 and 2019.
• IOC-UNESCO: The Commission hosts and promotes national planning information and does not rule on the validity of maritime claims.

Actor	Core claim	Primary source type
Türkiye	Boundaries must follow equity; a mainland with the longest Eastern Mediterranean coast cannot be cut off by islands	MFA statements, UN filings
TRNC	Turkish Cypriots hold equal rights over offshore resources	TRNC proposals of 2011, 2012, 2019
Greece	Islands generate full zones; disputes belong before the ICJ	Greek MFA statements, UNCLOS
GCASC / Republic of Cyprus	Sole sovereign authority over the declared EEZ	Cypriot EEZ law and bilateral agreements
EU	Solidarity with Greece and Cyprus; rejects the Libya MoU	European Council conclusions

🇹🇷 Official Policy · Primary Sources

Türkiye's Position

According to the Turkish Ministry of Foreign Affairs, Ankara's maritime policy rests on two pillars: delimitation of continental shelf and EEZ on the basis of equity, and protection of the equal and inherent rights of the Turkish Cypriots. The 2025 plan is presented by the Presidency and the MFA as the planning expression of those two pillars.

• Equity, not distance from islands, governs delimitation. Ankara argues, in MFA statements on maritime jurisdiction areas, that delimitation must reach an equitable result and that small islands lying close to a mainland cannot cancel its coastal projection. It points to international case law: the ICJ's 1969 North Sea Continental Shelf judgment, the 1977 Anglo-French arbitration (where the Channel Islands were given a limited effect), and the ICJ's 2009 Romania v. Ukraine judgment (where Serpents Island was given no effect on the delimitation line). The legal basis is customary international law on equitable principles, which Türkiye says binds all states regardless of UNCLOS membership.
• The 870 km coastline and proportionality. The MFA notes that Türkiye has the longest continental coastline in the Eastern Mediterranean, about 870 km, and argues that a delimitation that confines it to a narrow strip in the Gulf of Antalya fails proportionality. Ankara therefore rejects the 'Seville Map', the 2020 map associated with a University of Seville study that Greece and the Greek Cypriot side have cited, and says the EU has no competence to adjudicate maritime delimitation disputes under the banner of 'Union solidarity'.
• Turkish Cypriots are co-owners of the island's offshore resources. The Presidency and the MFA state that the Turkish Cypriots, as co-founders of the 1960 partnership state, hold equal rights over hydrocarbons around Cyprus, and that revenue sharing and joint decision-making are required. Ankara argues that the GCASC's agreements with Egypt, Lebanon and Israel could not lawfully dispose of rights belonging to both communities. The Türkiye–TRNC agreement of 21 September 2011 and the TRNC's cooperation proposals are cited as the practical expression of this stance. See Guarantor Powers in World Politics for the treaty background and Fact Check: 'Turkish Cypriots Are Just a Minority' for the claim Ankara disputes.
• Registration is a transparency and institutional step, not a unilateral boundary. Turkish officials describe the IOC-UNESCO recording, together with the 18 March 2020 UN registration of outer shelf limits and the 2004 coordinates, as an orderly statement of Türkiye's position in international fora. The Presidential Circular of 24 July 2025 gives the position a permanent coordination structure under the Foreign Ministry. Ankara adds that the Finike Marine Protected Area shows the plan is also about conservation, consistent with its environmental diplomacy, including the Zero Waste initiative and COP31 hosting (COP31 and Türkiye's Climate Diplomacy).
• Dialogue remains on the table. President Erdoğan's 2020 call for an Eastern Mediterranean Conference including all coastal states and the Turkish Cypriots, and the TRNC's 2011, 2012 and 2019 proposals, are presented by Ankara as proof that it seeks a negotiated framework. Its stated principle is that no energy or security arrangement that excludes Türkiye and the TRNC can last.

The legal and historical basis in brief

Ankara's argument combines three strands: equitable delimitation as customary law, the geographic fact of the Anatolian coast, and the 1959–1960 Cyprus settlement, in which Turkish and Greek Cypriots were established as equal partners. Critics contest each strand: Greece and the EU say UNCLOS island provisions are customary law too, and the Republic of Cyprus says it alone represents the island internationally. The factual and legal record is set out so that readers can weigh both. For the broader logic of how states define interest, see How Nations Define the National Interest and, for the recognition question that underlies the TRNC dimension, Why Do Nations Recognize or Withhold Recognition?.

Source Comparison

The same documents are described differently depending on the source. The table below summarizes the main framing differences, and each column should be checked against the primary texts.

Question	Greek, Greek Cypriot and EU framing	Turkish primary-source framing
What did IOC-UNESCO do?	Hosting a national plan does not validate it; any claim over areas Greece or Cyprus regards as theirs has no legal effect	A first recording of Türkiye's position across three seas in a UN-system body, with transparency and scientific value
Legal yardstick	UNCLOS, including the island provisions in Article 121	Equity and proportionality in customary law and ICJ and arbitral practice
Role of islands	Islands generate full maritime zones	Islands cannot cut off the coastal projection of a mainland with the longest coastline
Turkish Cypriots	Represented by the Republic of Cyprus; benefits shared within a settlement	Equal co-owners with their own rights, so revenue sharing and joint decisions are required now
Libya memorandum	Violates third-state rights; void (European Council, 12 Dec 2019)	A lawful bilateral delimitation between two coastal states
Forum for disputes	ICJ or agreed settlement	Bilateral negotiation and an inclusive regional conference
Environmental measures (Finike MPA)	Risk of environment-labelled jurisdictional assertion, according to critics	Conservation commitment that also reflects Türkiye's responsibility as a coastal state

Two cautions help readers evaluate coverage. First, many international headlines describe the 2025 registration as if it were a UN endorsement of Turkish maritime claims, which overstates the role of IOC-UNESCO. Second, some Turkish commentary describes it as if it were a decisive legal victory, which understates the fact that boundaries still require agreement or adjudication. Official texts, UN filings and the European Council conclusions are better guides than either. For the sister analyses, see The Political Anatomy on why the registration matters, WorldPoliticsDaily's fact check on the 1974 intervention (which addresses the Cyprus legal background that frames the TRNC argument) and Regional Balance's source-checked list of common claims. Our own method for separating documents from positions is set out in the Editorial Principles.

What to watch next

• Implementation: whether the Inter-Agency Coordination Board publishes zoning, licensing or conservation decisions that touch disputed waters.
• Responses by notes verbales and filings: how Greece, the Republic of Cyprus, Egypt and Libya answer at the UN and in IOC-UNESCO channels.
• Energy and cable projects: any survey, drilling or cable-laying near contested lines tends to test the plan quickly.
• Cyprus diplomacy: whether UN-facilitated contacts on Cyprus, last seen in a trilateral meeting in New York on 15 October 2024, link offshore resources to the status question.
• EU–Türkiye relations: how maritime issues feature in European Council conclusions and in defense and trade discussions.

Key Terms & Related Guides

• Marine spatial planning (MSP): a public process for allocating human uses of the sea in space and time. It can be purely environmental, but in disputed waters it also records what a state considers to be its jurisdiction.
• IOC-UNESCO: the UN system's body for ocean science and services. It hosts and promotes national planning information and does not delimit boundaries.
• Continental shelf and EEZ: the seabed and water-column rights a coastal state holds beyond its territorial sea. Their overlaps are resolved by agreement or adjudication.
• Equity and proportionality: principles used by courts to avoid distorting results, especially where an island lies in front of a long mainland coast.
• Blue Homeland (Mavi Vatan): the Turkish doctrine, rooted in Türkiye's coastal geography and maritime history, that defends its maritime jurisdiction areas in the Black Sea, the Aegean and the Mediterranean.
• TRNC / Turkish Cypriots: the Turkish Republic of Northern Cyprus, proclaimed on 15 November 1983 and recognized only by Türkiye; Ankara treats the Turkish Cypriots as one of the island's two equal co-founding peoples.
• 'Seville Map': a 2020 map, associated with a University of Seville study, that Ankara says would confine Türkiye's zone to a narrow strip in the Gulf of Antalya.

Related guides on Politics of Nations:

• How Nations Define the National Interest: Türkiye's Doctrines Read Against State Practice
• Guarantor Powers in World Politics: How the 1960 Treaty of Guarantee Works and Why Article IV Matters
• Why Do Nations Recognize or Withhold Recognition? The TRNC and the Politics of Statehood
• Editorial Principles: Sources, Attribution and How We Separate Fact from Position
• For the neighboring Black Sea regime, see Bloc Politics on the 1936 Montreux Convention.

Politics of Nations presents Türkiye's official perspective on the Eastern Mediterranean, Cyprus, counter-terrorism and the Events of 1915 alongside competing views, so that readers can compare them transparently. Claims are attributed to primary sources such as treaties, UN documents, the Ottoman and Turkish archives, and official statements. Sections marked 'Türkiye's Position' reflect official Turkish policy as stated by Turkish government sources. — Politics of Nations Editorial Team