Nearly three years of lower tensions between Greece and Turkey have done little to change Ankara’s position in the Aegean. Whereas Turkey once centered its disputes on Greek islands and territorial waters, today Turkey applies its claims to new areas of Greek activity, such as offshore wind farms, marine parks, and electrical cables.
This matters because energy projects can give practical effect to sovereignty and jurisdiction claims. For instance, Greece cannot develop an offshore wind farm without deciding where it has the authority to license it. Turkey has an interest in challenging such activity before it becomes established practice in areas where Ankara disputes or plans in the future to dispute Greek rights.
Turkey has an interest in challenging such activity before it becomes established practice in areas where Ankara disputes or plans in the future to dispute Greek rights.
Greece’s new framework for renewable energy illustrates this approach. Turkey objected to the plan in August 2026 and again referred to geographical formations whose sovereignty, it says, international treaties never transferred to Greece. Athens rejected the claim. The dispute over sovereignty is old, but Ankara is now using it to challenge where Greece can develop offshore energy.
Marine parks have followed a similar course. Greece announced two earlier this year, including one in the Aegean. Turkey responded with two parks of its own in August 2026, one covering waters between Lemnos and Samothrace. Athens says parts extend into areas where Greece claims maritime rights. Their boundaries therefore reflect competing views of who can exercise authority at sea.
Turkey has also increased its activity in the northeastern Aegean. Greek authorities have recorded frequent Bayraktar flights around Lemnos and Samothrace since mid-August. Ankara has renewed its objections to the Greek military presence on Aegean islands, while President Recep Tayyip Erdoğan has warned Athens against reinforcing islands Turkey says should remain demilitarized. Greece rejects this and is moving ahead with the Achilles Shield, its air and missile defense program with Israel.
Such disagreements have persisted despite improved Greek-Turkish relations since 2023. The Athens Declaration on Friendly Relations and Good-Neighbourliness expanded cooperation on migration, trade, and tourism. Yet they made little progress on the disputes that have produced past crises in the Aegean.
Energy and infrastructure make this arrangement harder to sustain. Diplomats can postpone a disagreement over maritime jurisdiction. A cable ship cannot operate without a government authorizing its work and issuing navigational warnings. In disputed waters, these decisions force Athens and Ankara to act on competing claims.
The Ocean Link shows what can happen. On September 11, 2026, the Greek station at Lemnos issued a navigational warning for the vessel to carry out cable maintenance northwest of Chios from September 13. Turkey has challenged Greece’s authority over such work in parts of the Aegean, and the same vessel has faced Turkish intervention twice this year.
Such incidents reveal how Turkey can press its claims without Greece accepting them. Challenging civilian vessels raises the political and security cost of projects in disputed waters and forces Athens to decide whether to proceed despite the risk of confrontation.
Washington can support talks between Greece and Turkey without taking a position on every legal dispute in the Aegean.
The Crete-Cyprus electricity cable illustrates the same problem to a larger scale. Greece expects seabed surveys to resume, possibly in October, including in waters affected by claims Turkey bases on its 2019 maritime agreement with Libya. Athens rejects Ankara’s claims and says it will not seek Turkish permission. Asking for Turkish approval could give weight to claims Greece considers illegal.
The issue also matters for Washington. The United States has supported energy links between Greece, Cyprus, and Europe, including projects that could reduce Cyprus’s energy isolation. Turkish pressure that delays these projects would affect plans that the United States has supported as part of closer regional energy cooperation.
Washington can support talks between Greece and Turkey without taking a position on every legal dispute in the Aegean. At the same time, it should oppose using military vessels to stop civilian survey or construction work.
Allowing such pressure to determine whether a project proceeds would give Turkey influence over infrastructure on the basis of maritime claims that Greece rejects.
The Crete-Cyprus cable may soon bring this question to the fore. When survey vessels return, both sides will have to decide how far they are prepared to press their claims.
