Greece protests to Ukraine after explosive-laden naval drone discovered in cave on tourist island

Greek authorities discovered a Ukrainian-made naval drone carrying approximately 100kg of explosives in a cave near Lefkada on May 8, 2026, with its engine still running after fishermen found it in the Ionian Sea. Greece lodged a formal protest with Ukraine, calling the incident 'extremely serious' and raising concerns that Ukraine's campaign against Russia's shadow fleet is expanding into the Mediterranean, following a March 2026 attack on a Russian tanker between Libya and Malta. The discovery has heightened tensions given Greece and Ukraine's November 2025 joint cooperation deal to produce naval drones, with reports that Kyiv sought veto power over Greek use amid concerns about Greece-Turkey territorial disputes. Greek authorities conducted a controlled explosion after removing detonators, while investigations continue into whether the drone was targeting Russian shipping or fell into the sea during transport, putting Greece's national security apparatus on red alert.

Explosive naval drone discovery

• ▪Greek authorities discovered an explosive-laden naval drone in a cave near Lefkada on Greece's western coast on May 8, 2026
• ▪The naval drone was estimated to be carrying around 100kg (220lb) of explosives

Ukrainian origin investigation

• ▪The naval drone had an estimated range of 432 miles (700km)
• ▪Two Greek news outlets reported that notes handwritten in Ukrainian were found aboard the naval drone
• ▪Greek Defence Minister Nikos Dendias said Greece has certainty that the naval drone was of Ukrainian origin
• ▪Ukraine's military has not commented on the naval drone discovered near Lefkada as of May 13, 2026
• ▪Both Greek and Ukrainian media identified the naval drone as likely a Ukrainian-made Magura drone

Greek maritime security vulnerabilities

• ▪Opposition defence spokesman Michalis Katrinis commented that all Greek women and men are realising that the country is an open vineyard
• ▪Greek authorities are investigating why the naval drone may have been in the Mediterranean
• ▪The naval drone incident has raised questions about Greece's maritime security and its vulnerability to emerging military technology

Black Sea drone warfare

• ▪Much of Ukraine's naval drone activity has been constrained to the Black Sea, which Ukraine and Russia both border
• ▪Ukraine has used naval drones to target Russian warships, tankers and naval bases since Moscow's full-scale invasion began in 2022
• ▪Ukrainian drones have repeatedly attacked Russian tankers carrying sanctioned oil in the Black Sea
• ▪In March 2026, Moscow accused Ukraine of hitting a sanctioned Russian tanker loaded with liquefied natural gas with uncrewed sea drones in the Mediterranean between Libya and Malta

Greek-Ukrainian defense cooperation

• ▪Greek newspaper Kathimerini reported on May 6, 2026 that Kyiv was seeking a veto over Greece's use of jointly-produced naval drones in military engagements
• ▪Greece and Ukraine struck a joint co-operation deal to produce naval drones in November 2025
• ▪The Greek-Ukrainian naval drone co-operation deal grants Athens access to Ukrainian technology for its own use

Political reactions to incident

• ▪Greek Defence Minister Nikos Dendias sought to downplay the significance of the naval drone's discovery on May 11, 2026
• ▪Greek Defence Minister Nikos Dendias said Greece has nothing to envy because Greece knows what the naval drone is and what it contains
• ▪The nationalist pro-Russian Hellenic Solution party called the naval drone incident a conscious military provocation