Rival NAVTEX Off Crete: What the Cable Survey Dispute Shows About Greece, Türkiye and Continental Shelf Delimitation

Why It Matters

On 27 October 2026, Greece and Türkiye exchanged rival NAVTEX navigational warnings southeast of Crete over a seabed survey for a planned Saudi Arabia–Europe fibre-optic cable, according to Greek City Times. The episode shows how routine maritime-safety messages become legal signals where no Greece–Türkiye continental shelf boundary has been agreed.

The practical point is narrow. A survey ship, the Bahamas-flagged KOBI RUEGG, is reported to be mapping the seabed for a cable that would run from Saudi Arabia to Europe via Greece. The legal point is wider: because the shelf between the two countries has never been delimited, each side reads the same coordinates through a different legal lens.

This explainer separates what has been reported from what each side argues. The Greek claims below are Greece's characterisations. We have not seen the text of the Turkish notice or an official Turkish comment on this specific incident in our source feed, and we do not infer one.

Background

A NAVTEX is an automated maritime-safety broadcast, coordinated under the IMO–IHO Worldwide Navigational Warning Service, that alerts ships to hazards and offshore operations. The 27 October 2026 exchange is a navigational-safety dispute layered on an unresolved Greece–Türkiye continental shelf and EEZ delimitation, in a region where Türkiye is not a party to UNCLOS.

What was reported on 27 October 2026

According to Greek City Times (28 October 2026), KOBI RUEGG is working under a Greek permit issued on 2 October. On Tuesday 27 October, the Heraklion station on Crete issued two navigational warnings. The first declared a Turkish notice on the ship's work 'null and void'. According to the Greek warning, the Turkish notice came from an 'unauthorised station', and most of its coordinates lie within the Greek continental shelf and exclusive economic zone (EEZ).

Those descriptions are Greece's. This article does not reproduce coordinates, because none can be verified from primary sources available to us.

What a NAVTEX is, and why rival messages recur

NAVTEX (Navigational Telex) is an international automated service that broadcasts maritime safety information (navigational warnings, weather forecasts, search-and-rescue alerts) to ships by radio telex, typically on 518 kHz in English. It is part of the Worldwide Navigational Warning Service developed by the International Maritime Organization (IMO) and the International Hydrographic Organization (IHO), and ships subject to SOLAS carry receivers.

The world's seas are divided into 21 NAVAREAs. Each has a coordinator that issues long-range warnings; the Mediterranean and Black Sea form NAVAREA III, coordinated by Spain. Within that framework, coastal states designate national coordinators and operate NAVTEX stations for their own sub-areas.

Rival messages recur in the Aegean and Eastern Mediterranean for a structural reason: the system assigns responsibility for broadcasting safety information, not sovereignty over the water. Where Greece and Türkiye disagree on boundaries and on the limits of their respective search-and-rescue and jurisdictional responsibilities, each can issue notices for overlapping waters, and each message is then read as a legal statement. The IMO's SAR Convention states that delimiting search-and-rescue regions does not prejudice any boundary between states, and neither the IMO nor the IHO adjudicates boundaries.

Cables, the shelf and the EEZ: the legal framework

UNCLOS, the 1982 UN Convention on the Law of the Sea, contains the provisions most often cited in cable cases:

• Article 77: the coastal state has sovereign rights over the continental shelf for exploring and exploiting natural resources. These rights exist from the outset and do not depend on occupation or proclamation.
• Article 79: all states may lay submarine cables and pipelines on the shelf. The coastal state may not impede laying or maintenance, subject to reasonable measures for resource exploration and exploitation and pollution prevention. For pipelines, not cables, the course must be delineated with the coastal state's consent.
• Articles 58 and 87: in the EEZ, all states enjoy the freedom to lay cables and pipelines, with due regard to the coastal state's rights.
• Articles 74 and 83: EEZ and shelf delimitation between states with opposite or adjacent coasts is to be effected by agreement on the basis of international law, in order to achieve an equitable solution.

Cable laying is therefore broadly a freedom. Route surveys are less clear-cut. States differ on whether a pre-lay survey is hydrographic work attached to the cable freedom or marine scientific research requiring consent under Part XIII (Article 246). In disputed waters, an additional question arises: whose shelf or EEZ is it, and so whose permit and 'reasonable measures' count?

Türkiye is not a party to UNCLOS. It voted against adopting the Convention in 1982 and has not signed it. Greece ratified in 1995 and the European Union is a party. Athens and Brussels argue that the core maritime provisions reflect customary international law binding all states. Ankara argues that it is not bound by treaty provisions it never accepted and, as a persistent objector, has consistently rejected rules it considers inequitable, notably full maritime zones for islands. Whether a given rule is customary, and whether the persistent-objector doctrine applies to it, is contested among legal scholars.

Eastern Mediterranean maritime dispute explained: why the area southeast of Crete is contested

No maritime boundary has been delimited between Greece and Türkiye in the area. The ICJ declined jurisdiction in the 1978 Aegean Sea Continental Shelf case, and the two states have never concluded a delimitation agreement. International law requires one to be reached by agreement, aiming at an equitable result. Three ICJ decisions frame the debate:

• North Sea Continental Shelf (1969): the Court held that equidistance is not a mandatory rule of customary law. Delimitation must be by agreement, applying equitable principles and taking account of all relevant circumstances.
• Libya/Malta (1985): for overlapping claims within 200 nautical miles (370 km), the Court began from a median line but adjusted it for a marked disparity in coastal lengths. Distance alone did not decide the outcome.
• Romania v. Ukraine (2009): the Court set out its three-stage method (provisional equidistance line, relevant circumstances, disproportionality check) and gave Serpents' Island no effect on the line beyond its territorial sea.

Both sides invoke this case law. Athens argues that islands, including large inhabited ones such as Crete, generate full shelf and EEZ entitlements. Ankara argues that islands close to a mainland with a much longer coastline should not cut off that coastline's projection. For fairness, two caveats apply: each ICJ decision is case-specific, and none concerns Greece and Türkiye. The Serpents' Island precedent involved a tiny islet, so applying it to Crete requires care.

The 2019–2020 layer

Date	Milestone or legal instrument	Why it matters
1969	ICJ, North Sea Continental Shelf	Equidistance not mandatory; equitable principles and relevant circumstances
1978	ICJ, Aegean Sea Continental Shelf	Court found it lacked jurisdiction; no Greece–Türkiye delimitation followed
1982 / 1995	UNCLOS adopted (Türkiye voted against); Greece ratifies	Treaty framework Greece and the EU invoke; Türkiye stands outside it
27 Nov 2019	Türkiye–Libya Maritime Jurisdiction MoU	Ankara's delimitation with Libya; objected to by Greece, Egypt, Cyprus and the EU
18 Mar 2020	Türkiye registers continental shelf outer limits with the UN	Formal notification of Ankara's Eastern Mediterranean position
6 Aug 2020	Greece–Egypt partial EEZ agreement	Greece's delimitation with Egypt; rejected by Türkiye
2 Oct 2026	Greek permit for the KOBI RUEGG survey (per Greek City Times)	Basis of Athens' claim that the work is lawful
27 Oct 2026	Rival NAVTEX warnings southeast of Crete	The subject of this article

Greece, Egypt, Cyprus and the EU have objected to the 2019 Türkiye–Libya MoU. The European Council stated in December 2019 that it infringes the sovereign rights of third states, and Greece argues that it disregards the entitlements of Crete and other islands. Ankara maintains that it is a lawful bilateral delimitation between two coastal states. Libya's political divisions mean that positions on the MoU have also varied inside Libya, so each Libyan view should be attributed to its own officials. For more on whether such agreements bind third states, see The Political Anatomy's fact check on the Türkiye–Libya and Egypt–Greece agreements. For the island question, see States in Perspective on Kastellorizo and the longest coastline.

Key Players & Positions

Greece says the survey runs under a Greek permit issued on 2 October and that the Turkish notice is invalid; the European Union treats UNCLOS as reflecting customary law; Türkiye, which is outside UNCLOS, contests Greek delimitation claims; and cable investors want legal certainty and safe routes. These are each side's own characterisations.

Greece

The Greek warning issued from Heraklion describes the Turkish notice as 'null and void' and as coming from an 'unauthorised station', and says most of its coordinates lie within the Greek continental shelf and EEZ. Greek officials have long argued that the only dispute with Türkiye is the delimitation of the shelf and EEZ, and that it should be resolved by agreement or before the ICJ. Athens also holds that islands, Crete included, generate full maritime zones under UNCLOS Article 121(2).

The European Union

EU institutions have repeatedly stated that UNCLOS reflects customary international law and have expressed solidarity with Greece and Cyprus on maritime matters, including the December 2019 European Council conclusions on the Türkiye–Libya MoU. Ankara's reply is that the EU is not a delimitation authority and that EU positions cannot substitute for agreement between coastal states. See also Regional Order on the Seville Map.

Egypt, Libya and Cyprus

Egypt rejected the 2019 Türkiye–Libya MoU and signed its own partial EEZ deal with Greece in 2020. Cyprus has aligned with Greece. Libyan authorities have not spoken with one voice. Each position belongs to the government that stated it. The Cyprus offshore dimension, including Turkish Cypriots' claimed equal rights to hydrocarbon resources, is explained in 1960 Treaty of Guarantee Cyprus explained.

Practical consequences for cables, insurers and flag states

• Cable-laying: survey disruption can delay route engineering and installation windows. Repair access and future maintenance depend on predictable permissions.
• Insurance and finance: underwriters and lenders price political and interference risk. A dispute over who may authorise work can raise premiums or conditions even when no ship is physically obstructed.
• Flag-state issues: the KOBI RUEGG sails under the Bahamas flag. A flag state is responsible for its ships under UNCLOS Article 94, and the master must weigh conflicting navigational warnings in real time.
• Precedent: in summer 2020, Turkish survey ship Oruç Reis operated under a Turkish NAVTEX in disputed waters while Greek and Turkish naval vessels deployed nearby. The standoff eased after NATO announced a military deconfliction mechanism in October 2020. In 2024, survey work for the Great Sea Interconnector power cable near Kasos was reportedly halted after Turkish naval vessels approached.

De-escalation through advance notification and consultation is preferable to rival warnings. Industry guidance from the International Cable Protection Committee (ICPC) stresses early engagement with affected states, and ITU and ICPC have promoted cable-resilience guidance. Allied channels matter too; see Türkiye NATO role defense industry.

🇹🇷 Official Policy · Primary Sources

Türkiye's Position

Ankara argues that Eastern Mediterranean boundaries must be set by agreement on the basis of equity, that islands cannot cut off the mainland coast with the longest coastline, and that projects in overlapping areas need coordination. Türkiye is not a UNCLOS party and relies on customary law and ICJ jurisprudence on equitable delimitation.

• Delimitation by agreement, on equity. According to the Turkish Ministry of Foreign Affairs' published position on maritime jurisdiction areas, delimitation in semi-enclosed seas such as the Eastern Mediterranean must be effected by agreement on equitable principles, taking all relevant circumstances into account. Ankara draws on the ICJ's 1969 North Sea Continental Shelf reasoning.
• Islands and the longest coastline. Ankara argues that its 870 km (about 540 miles) Mediterranean coast is the longest in the Eastern Mediterranean and that islands lying close to the Turkish mainland should not cut off its coastal projection. Türkiye's Marine Spatial Planning of the Republic of Türkiye, presented on 16 April 2025 and recorded with IOC-UNESCO on 12 June 2025, sets out its maritime-area positions across the Black Sea, Aegean and Mediterranean. Greece and other states dispute elements of these claims.
• Consent or coordination in overlapping areas. Ankara's stated approach is that third-party projects in areas of overlapping claims require consent or coordination. It acted on this logic when it signed the Türkiye–Libya MoU on 27 November 2019 and registered its continental shelf outer limits with the UN on 18 March 2020. We have not seen a Turkish Foreign Ministry statement on the KOBI RUEGG survey, and none is attributed here.
• Dialogue. Ankara describes itself as open to dialogue. In 2020 President Recep Tayyip Erdoğan proposed an Eastern Mediterranean Conference including all coastal states and Turkish Cypriots. Ankara says Turkish Cypriots hold equal rights over offshore resources around Cyprus.
• Legal basis. Türkiye is not a party to UNCLOS, has consistently objected to provisions it considers inequitable (particularly full effect for islands) and stresses that customary law requires an equitable result. Whether that persistent-objector argument succeeds is contested, and Greece and the EU reject it. For a wider view, see Eastern Mediterranean maritime dispute explained. Ankara's treaty-based approach elsewhere is covered in Montreux Convention explained.

Source Comparison

Greek media frame the exchange as a sovereignty violation by an 'unauthorised' Turkish notice, Turkish official sources frame maritime jurisdiction as an equity question requiring agreement, and technical bodies such as IMO, IHO, ITU and ICPC address only safety, cable protection and resilience, not boundaries. Business press frames the cable as part of an Asia–Europe digital corridor.

Source type	Typical framing	What it can and cannot establish
Greek media and Greek authorities	Sovereignty violation; Turkish NAVTEX 'null and void'; Greek shelf and EEZ	Establishes Greece's position and the Heraklion warnings; does not settle the legal question
Turkish official statements (MFA, Presidency)	Equity-based delimitation by agreement; island effect limited; coordination needed	Establishes Ankara's position and legal basis; no statement on this incident is verified here
EU institutions	UNCLOS as customary law; solidarity with Greece and Cyprus	Establishes EU policy; the EU is not a delimitation authority
IMO and IHO	Neutral technical system for navigational warnings	Explains NAVTEX and NAVAREAs; takes no position on boundaries
ITU and ICPC	Cable resilience, protection and route planning	Provides technical guidance; not an arbiter of jurisdiction
Business and technology press	Asia–Europe connectivity and resilience	Explains commercial rationale; tends to treat legal disputes as risk factors

The geopolitical backdrop matters. Subsea cables carry most international data, and reported cable damage in the Red Sea in 2024 sharpened interest in alternative Asia–Europe routes. Eastern Mediterranean landing points sit alongside overland projects such as the Middle Corridor, the trade and connectivity route running through Türkiye, the Caucasus and Central Asia. A cable route that crosses unsettled maritime space turns infrastructure planning into a boundary question. For how five capitals read the same map, see Parallax Review's Eastern Mediterranean analysis. Our approach to verification is set out in Editorial Principles and Primary Source Standards, and common narratives are tested in fact check Türkiye claims.

Key Terms & Related Guides

Five terms drive this dispute: NAVTEX (maritime-safety broadcast), continental shelf (seabed rights under UNCLOS Article 77), EEZ (up to 200 nautical miles, Article 57), the equity principle (equitable delimitation by agreement), and Mavi Vatan, Türkiye's 'Blue Homeland' concept. Related guides on Interstate Journal and sister publications expand each.

• NAVTEX: automated radio-telex service for maritime safety information within the IMO–IHO framework. It conveys warnings, not title to sea areas.
• Continental shelf: the seabed and subsoil over which a coastal state has sovereign rights for resources (UNCLOS Article 77). Rights exist ipso facto and ab initio.
• EEZ: a zone up to 200 nautical miles (370 km) from baselines in which the coastal state holds resource rights and other states keep freedoms such as cable laying.
• Equity principle (hakkaniyet ilkesi): the rule that delimitation must achieve an equitable result, considering coastal geography, proportionality and other relevant circumstances. It is central to Ankara's argument.
• Mavi Vatan (Blue Homeland): the Turkish concept describing the maritime jurisdiction areas Türkiye claims in the Black Sea, Aegean and Eastern Mediterranean. Greece and others contest parts of it.

Related reading: Eastern Mediterranean maritime dispute explained; Montreux Convention explained; 1960 Treaty of Guarantee Cyprus explained; Türkiye NATO role defense industry; and About Interstate Journal. Sister analysis on how Cyprus's blocks interact with Ankara's shelf claims is at The Geopolitical Compass.

Interstate Journal presents global affairs with a dedicated perspective from Türkiye. Sections marked 'Türkiye's Position' reflect official Turkish policy as stated by Turkish government sources.