On October 2, 2025, Turkey issued a NAVTEX—the third in less than a month—for the Piri Reis research vessel, authorizing seismic exploration between October 4-14, 2025, in areas of the central Aegean Sea that fall within Greek continental shelf zones. The NAVTEX, a navigational text message warning used to provide short-range maritime safety information in coastal waters, demonstrated Turkey’s disregard of international maritime law and contempt for Greece’s sovereign rights.
Viewing Turkey’s move as a provocation, Greece issued a counter-NAVTEX, valid until October 25, stating that Turkey’s message illegally encompasses areas within the Greek continental shelf. Turkey’s unilateral action is heightening regional tensions, but it also sets a dangerous precedent by promoting a policy of “facts on the water”—attempting to create rights through de facto activity rather than legal negotiation, a tactic China often employs against the Philippines and other states in the South China Sea.
The international legal community does not support Turkey’s interpretations and rejects its legal framework for defining territorial rights in the Aegean.
Turkey’s legal claims in the Aegean contrast with those of Greece. The unique maritime landscape of the Aegean—a semi-enclosed sea populated with more than 2,000 islands—long has been the cause of conflict between the two countries. The Treaties of Lausanne (1923) and Paris (1947) gave Greece sovereignty over many Aegean islands and islets, but Ankara challenges that, citing supposed treaty ambiguities. The international legal community does not support Turkey’s interpretations and rejects its legal framework for defining territorial rights in the Aegean. Greece, meanwhile, seeks consistency in its reliance on international law.
Greece signed the 1982 United Nations Convention on the Law of the Sea (UNCLOS), which grants states maritime rights based on island geography. Turkey has contested UNCLOS’s application in the Aegean context, as it disadvantages countries such as its own with extensive mainland coastlines but relatively few islands. Turkey refused to sign the treaty, arguing that if Greece invokes its right to extend its territorial waters out to twelve nautical miles—it currently claims six—per the terms of UNCLOS, Turkish access to international waters would be severely limited and all but choked out.
Instead of signing UNCLOS or entering into negotiated agreements, in 1995, Turkey publicly threatened that if Greece invokes its right to extend its territorial waters under UNCLOS, it would constitute a casus belli or “cause for war,” violating Article 2(4) of the United Nations Charter, which prohibits “threats or use of force against the territorial integrity” of another United Nations member state.
The Piri Reis NAVTEX episode serves as further evidence of the continued distrust between the two countries. When Ankara first issued a NAVTEX for the Piri Reis in mid-September, Athens deployed more than sixty fighter jets, the entire Hellenic Navy fleet, special forces on thirty islands, and army units near the northern border with Turkey—demonstrating Greek readiness to defend national sovereignty. Turkey issued another NAVTEX on September 18, repeating its view that certain Greek islands must stay demilitarized, referencing the prohibition on militarization found in the Lausanne and Paris treaties.
If Ankara wishes to be seen as a credible actor, it should start by recognizing and respecting the legal framework that governs maritime affairs.
Non-recognition of UNCLOS does not automatically invalidate Turkey’s maritime claims; customary international law also applies. With respect to the Aegean’s continental shelf and Exclusive Economic Zones, Ankara insists that maritime delimitation must be based on equitable principles that consider coastlines and proximity, especially when islands are close to another state’s mainland. Turkey has relied on the cases of Libya v. Malta (1985) and Nicaragua v. Colombia (2012) to support its claims that international courts can limit the maritime rights of small islands in adjudicating disputes when necessary to serve an equitable outcome. Turkey’s reliance on those judgments, however, is legally flawed; the decisions do not translate to the Aegean context—the ideas are similar, but the facts are different, which would alter the court’s determination.
Though both Greece and Turkey may have valid claims and concerns about establishing the legal identity and status of the Aegean’s waters, Turkey’s methods are questionable—it cannot assert unilateral rights in contested areas without judicial oversight or engagement. Furthermore, Ankara undermines its credibility when it relies on faulty legal arguments and instigates political conflict by using hard-power tactics, diminishing its claim of good faith in seeking equitable treatment.
In choosing selective interpretations, refusing to sign UNCLOS, threatening Greek sovereignty, and using research activities such as the Piri Reis NAVTEX as leverage for territorial gains, Turkey undermines its position as a serious player in a rules-based international order. If Ankara wishes to be seen as a credible actor, it should start by recognizing and respecting the legal framework that governs maritime affairs. It cannot simultaneously reject international law and then claim victimhood when it is criticized for violating it. The Aegean’s unique geography defies simple solutions, but regional peace and stability can be achieved only when law prevails over force, and dialogue over intimidation.
