Greece, Turkey clash over protected Aegean marine areas

A stint of unfamiliar calm between Greece and Turkey lasted less than three years.

After a devastating earthquake struck Turkey in February 2023 and Greece provided substantial aid, the two countries came closer together. They then signed the Athens Declaration on Friendly Relations and Good-Neighbourliness in December 2023, a further step to improved relations.

During this unusual time of calm, neither government moved to resolve long-lasting Greek-Turkish disputes, which mostly involve marking maritime boundaries . As a result, even a measure ostensibly aimed at protecting the environment has reignited regional tensions.

The latest dispute was triggered by Turkey's designation of two marine parks in the Aegean Sea and eastern Mediterranean earlier this month. The park in the northeastern Aegean includes a protected area in the waters between the Greek islands of Lemnos and Samothrace. The southern park lies east of Rhodes and surrounds the Greek island of Kastellorizo.

For decades, Greece and Turkey have been at odds over the delineation of their maritime borders in the Aegean and the related economic rights, such as claims to natural resources like oil .

Greece's Foreign Ministry was quick to react to the announcement, calling the establishment of the parks "illegal." In a statement, it said the designation of Turkish marine parks in areas outside Turkey's territorial waters has no legal validity.

Greek Prime Minister Kyriakos Mitsotakis said at a Cabinet meeting earlier this week that he wanted to maintain good relations with neighboring countries. However, he stressed that "areas under Greek sovereignty are determined by international law" and that Greece is "always ready to defend them."

For its part, Greece also announced two marine parks in 2025 — in the Ionian Islands and the southern Cyclades, both within Greek territorial waters. At the time, Turkey reacted in a clearly worded statement: "Unilateral actions should be avoided in closed or semi-closed seas such as the Aegean and the Mediterranean."