Greece Plans Maritime Expansion, Risking Possible War with Türkiye

Greece’s announcement that it intends to further extend its territorial waters marks a deliberate assertion of sovereignty that reopens one of the most sensitive fault lines in relations with Türkiye. Speaking in parliament on Jan. 16, Foreign Minister of Greece George Gerapetritis confirmed that Athens plans additional extensions beyond the 6 nautical miles that currently define Greek territorial waters in the Aegean Sea, aligning the basin with steps already taken elsewhere.

“Today, our sovereignty in the Aegean Sea extends to 6 nautical miles,” he said. “As there was an agreement with Egypt, as there was an agreement with Italy, there will also be a (further) extension of the territorial waters.”

Greece already expanded its territorial waters in the Ionian Sea from 6 to 12 nautical miles following a bilateral agreement with Italy, and signed a maritime delimitation accord with Egypt in the eastern Mediterranean.

The Aegean, however, has remained excluded due to Türkiye’s long-standing objection and the 1995 decision by the Turkish parliament declaring any unilateral Greek extension beyond six miles a “casus belli”, or cause for war.

“We Will Not Negotiate Sovereignty”

The Aegean dispute goes beyond territorial waters, touching on airspace, overflights, continental shelves, and exclusive economic zones (EEZs) in a semi-enclosed sea dotted with Greek islands close to the Turkish mainland. Greek officials insist that international maritime law permits a 12 nautical mile limit, while Ankara argues that the Aegean’s geography makes such an extension unacceptable.

Gerapetritis framed recent steps as part of a broader maritime doctrine, linking territorial waters to environmental initiatives and national sovereignty, claiming that Greece would not retreat from its positions, further unveiling the boundaries of two planned marine parks in July, including one in the Aegean covering 9,500 square kilometers, initially around the southern Cyclades.

Ankara objected to the move, seeing it as a precedent-setting assertion of jurisdiction. Türkiye has also previously responded to what it describes as Greek unilateralism in the Aegean with counter-measures of its own.

In August 2025, Ankara formally designated two Marine Protected Areas (MPAs) after Greece declared marine parks in the Aegean without consultation. The zones were registered in Türkiye’s Marine Spatial Planning Map submitted to the United Nations, which Turkish officials said was intended for environmental protection while also affirming sovereign rights. The Turkish government said any Greek attempt to impose unilateral maritime realities in the Aegean was “null and void,” adding that Türkiye remained open to regional environmental cooperation but not “at the cost of its national interests.”

Constraint Management Between NATO Allies

Despite the sharp legal disagreement, Athens and Ankara have eased tensions in recent years through dialogue and confidence-building measures. Greece maintains that the only dispute open for discussion is the delimitation of maritime zones, including the continental shelf and EEZ. Türkiye, for its part, argues that Greek domestic politics incentivize hardline positions.

On Jan. 15, Turkish Foreign Minister Hakan Fidan said the perception of Türkiye as a threat has always played a driving role in Greek politics. He added that Greek leaders face a choice “between resolving problems with Türkiye and bringing peace to the region, or risking their own political career,” concluding that the situation needs to come to an end.

Regional Alignments and Security Signaling

The maritime debate unfolds alongside expanding security cooperation involving Greece, Israel, and Greek Cyprus. On Dec. 17, plans were disclosed for studying a joint brigade-level rapid reaction force in the eastern Mediterranean.

Days later, the Israel Defense Forces announced a trilateral military cooperation work plan with Greece and Greek Cyprus, covering joint exercises, training, working groups, and strategic dialogue - a move that risks drawing Greece into broader regional controversies. Given the IDF’s conduct in ongoing conflicts and the scrutiny it faces internationally for the genocide in Gaza, closer institutional alignment is likely to expose Athens to heightened diplomatic criticism and public backlash well beyond the Eastern Mediterranean.

Athens highlights its own defense modernization, pointing to new frigates and broader naval upgrades, while stressing continued dialogue with Ankara. A meeting between Turkish President Recep Tayyip Erdoğan and Greece Prime Minister Kyriakos Mitsotakis is expected in February in Ankara, underscoring parallel tracks of engagement and deterrence as Greece advances its maritime strategy.