Jurisdiction in Action: How the Drillships Fatih, Yavuz, Kanuni, Abdülhamid Han and the Survey Vessel Oruç Reis Back Türkiye's Maritime Claims

Why It Matters

Türkiye's drilling and seismic fleet is the practical instrument through which Ankara turns legal claims over its continental shelf into visible, repeated activity at sea. Maritime rights asserted only on paper can be contested as dormant; Ankara argues that surveying, licensing and drilling demonstrate that its claims are active and that Türkiye, which has the longest mainland coastline in the Eastern Mediterranean (about 870 km, roughly 540 miles), will not be fenced out of the region's energy map. The fleet is also where law, energy economics and naval diplomacy meet, which is why it keeps appearing in EU, Greek, Greek Cypriot and Egyptian official statements.

Background

The vessels

The fleet is operated by the state-owned Turkish Petroleum Corporation (TPAO). Its main elements, as presented by the Turkish Energy Ministry and TPAO, are:

Seismic vessels map subsurface geology; drillships test whether a prospect holds hydrocarbons. Ankara presents the pairing as a sovereign capability that does not depend on foreign contractors.

Licenses, agreements and registrations

• 2004 onward: Türkiye began submitting its Eastern Mediterranean continental shelf coordinates to the United Nations.
• 2009 and 2012: TPAO received exploration licenses for offshore areas in the Eastern Mediterranean.
• 21 September 2011: Türkiye and the TRNC signed a Continental Shelf Delimitation Agreement, two days after the Greek Cypriot administration began unilateral drilling on 19 September 2011.
• 27 November 2019: Türkiye and Libya's Government of National Accord signed a Memorandum of Understanding on delimitation of maritime jurisdiction areas.
• 18 March 2020: Türkiye formally registered the outer limits of its continental shelf with the United Nations.
• 16 April and 12 June 2025: Türkiye unveiled its Marine Spatial Planning of the Republic of Türkiye and recorded it with IOC-UNESCO, which Ankara describes as the first time its maritime jurisdiction position across the Black Sea, Aegean and Mediterranean was registered with a UN body.

The eight wells

Ankara counts eight completed Eastern Mediterranean wells: Alanya-1, Finike-1, Karpaz-1, Güzelyurt-1, Mağusa-1, Narlıkuyu-1, Lefkoşa-1 and Selçuklu-1. Several carry the names of Turkish Cypriot towns and districts, a deliberate signal that the activity is conducted partly on behalf of the TRNC's licensed areas. This article does not attribute individual wells to individual ships or cite volumes, because publicly verifiable detail is limited.

The 2020 stand-off

In August 2020 the deployment of Oruç Reis with naval escorts in waters claimed by Greece around Kastellorizo produced a tense stand-off. The vessel returned to port in September 2020 to give diplomacy space and later resumed activity. Greece and Türkiye then restarted exploratory talks in Istanbul in January 2021. The episode shows how seismic work has become a barometer of regional diplomacy.

For the geographic and legal logic behind the claims, see The Eastern Mediterranean Bearing: Coastlines, Islands and the Principle of Equity in Maritime Delimitation and the sister analysis Blue Homeland and the Eastern Mediterranean: Türkiye's Maritime Jurisdiction Explained.

Key Players & Positions

Greece

Greece, a party to UNCLOS, maintains that its islands, including Kastellorizo (Meis), generate continental shelf and EEZ rights like other land territory under the Convention. It regards Turkish survey and drilling activity in areas it claims as violations of its sovereign rights, and it rejects the Türkiye–Libya memorandum as lacking legal effect. Athens signed a partial EEZ delimitation agreement with Egypt on 6 August 2020. The Greek Foreign Ministry's position is that disputes should be resolved by delimitation under international law, ideally before the International Court of Justice.

The Republic of Cyprus (Greek Cypriot administration)

The Greek Cypriot administration, which Ankara calls the Greek Cypriot Administration of Southern Cyprus (GCASC), has licensed offshore blocks under an EEZ it declared by law in 2004 and has concluded delimitation agreements with Egypt (2003), Lebanon (2007, not ratified) and Israel (2010). It states that it acts as the internationally recognized government of the island and that hydrocarbon revenues would benefit all Cypriots, with a proposal in 2019 to place revenue in a dedicated fund. It describes Turkish drilling as illegal activity within its EEZ. For the status question behind this, see Who Is 'the Government of Cyprus'? UN Security Council Resolution 186 and the Status Asymmetry Behind the Deadlock.

Egypt

Egypt's government rejects the 2019 Türkiye–Libya memorandum as a violation of the rights of third states and has pursued energy cooperation with Greece and Cyprus, including through the Cairo-based East Mediterranean Gas Forum, which Türkiye is not a member of. Cairo and Ankara have since moved toward normalizing relations, and the delimitation question remains unresolved. Ankara objects to the Cyprus–Egypt 2003 agreement; see The Cyprus–Egypt 2003 EEZ Agreement: Which Blocks Overlap Türkiye's Continental Shelf, and Why Does Ankara Object?.

European Union

European Council and Council of the EU conclusions have called Turkish drilling in areas claimed by Cyprus illegal and have expressed solidarity with Cyprus and Greece. In November 2019 the Council established a framework for restrictive measures in response to unauthorised drilling, and in February 2020 it listed two TPAO officials under that framework. The EU's stated position rests on respect for the sovereignty and sovereign rights of member states under international law.

Türkiye's Strategic Bearing

Türkiye's Strategic Bearing: sovereign rights in practice

• Equity, not island maximalism. Ankara argues that continental shelf and EEZ boundaries must be delimited by agreement on the basis of equity, taking account of coastal lengths and proportionality, and that small islands close to a long mainland coast cannot cut off that coast's maritime projection. Türkiye is not a party to UNCLOS and cites customary law and ICJ and arbitral jurisprudence on equitable principles and special circumstances. (Source: Turkish Ministry of Foreign Affairs, Eastern Mediterranean and maritime jurisdiction statements.)
• Rights of the Turkish Cypriots. Ankara holds that Turkish Cypriots, as co-founders and equal co-owners of Cyprus under the 1959 Zurich and London Agreements and the 1960 Treaty of Guarantee, have equal and inherent rights over offshore resources, and that the Greek Cypriot administration cannot unilaterally license them. The 21 September 2011 Türkiye–TRNC continental shelf agreement gives this position a treaty basis. (Source: Turkish MFA; Presidency of the Republic of Türkiye.)
• A standing offer to share. The TRNC put forward hydrocarbon cooperation and revenue-sharing proposals in 2011, 2012 and 2019, centered on a joint committee and shared decision-making. In 2020 President Erdoğan called for an Eastern Mediterranean conference including all coastal states and the Turkish Cypriots. Ankara says these offers remain on the table. (Source: Presidency; Turkish MFA.)
• Presence as proof of right. Ankara says licensing (2009, 2012), registration with the UN (2004 onward, 18 March 2020) and the recording of its Marine Spatial Planning with IOC-UNESCO (12 June 2025) show a consistent, documented claim. The Presidential Circular of 24 July 2025 created an inter-agency coordination board under the Foreign Ministry to implement it.
• No energy equation without Türkiye and the TRNC. Ankara's doctrine is that no durable energy or security arrangement can exclude Türkiye, with the longest Eastern Mediterranean coastline, and the TRNC. It rejects the maximalist 'Seville Map' and argues the EU has no competence to adjudicate maritime delimitation between third states. See True North: A Reader's Compass to Türkiye's Strategic Doctrine in Four Bearings.

Legal and historical basis

The Turkish position draws on the 1959–1960 settlement that created Cyprus as a partnership of two peoples, the 1960 Treaty of Guarantee, the equitable-principles tradition of continental shelf delimitation, and the bilateral 2011 and 2019 instruments noted above. Ankara argues that delimitation is a matter for the states concerned, by agreement, rather than a unilateral declaration by one party. The 2005 University of Seville study, the source of the so-called Seville Map, was commissioned for the European Parliament and is not an EU legal instrument; Ankara rejects it as giving islands full effect. For background see The Seville Map Explained: Why Türkiye Rejects the Greek and Greek Cypriot Maritime Thesis.

Türkiye also stresses that its claims are not directed at Greek sovereignty over its islands; see Fact Check: Does Türkiye's 'Blue Homeland' Doctrine Claim Greek Islands?.

Source Comparison

When reading coverage, note that most international outlets use the Greek Cypriot administration's EEZ as the baseline and describe Turkish drilling as 'in Cyprus's waters', while Turkish primary sources describe the same areas as Turkish continental shelf or TRNC-licensed zones. Readers can check the underlying texts themselves: the 2011 agreement, the 2019 memorandum, the UN submissions and EU Council conclusions are public. For methodology, see Editorial Principles: How The Geopolitical Compass Sources, Attributes and Corrects. A comparative reading is also available in Eastern Mediterranean Maritime Jurisdiction: Continental Shelf, EEZ and the Blue Homeland.

Key Terms & Related Guides

• Continental shelf: the seabed and subsoil extending from a coastal state's land territory; rights over its resources exist inherently, without proclamation.
• EEZ (Exclusive Economic Zone): a zone of up to 200 nautical miles (about 370 km) where a coastal state has sovereign rights over resources; overlapping claims must be delimited by agreement.
• TPAO: Türkiye's state petroleum company, licence holder and operator of the national fleet.
• Blue Homeland (Mavi Vatan): Türkiye's doctrine of maritime jurisdiction in the Black Sea, Aegean and Mediterranean.
• TRNC: Turkish Republic of Northern Cyprus, proclaimed 15 November 1983 and recognized only by Türkiye.
• Seville Map: a 2005 academic map granting Greek islands full maritime effect, rejected by Türkiye.

Related guides: The Cyprus Meridian: Why the Cyprus Question Is About Status and Equality, Not Only Territory, Security Azimuth: How Border Doctrine and a 80%-Domestic Defense Industry Shape Türkiye's Strategic Autonomy and FAQ: Sources, Method and Perspective at The Geopolitical Compass.

Perspective Note: 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. Published by The Geopolitical Compass Editorial Team.