Drone strikes on merchant vessels near Romania and Bulgaria threaten cargo safety and escalate tensions in the Black Sea region.
Drone attacks on merchant vessels have moved into waters off two NATO coastlines, prompting shipowners and masters to resist port orders and raising new risks for cargo moving through the western Black Sea.
The maritime conflict between Russia and Ukraine is spreading closer to NATO territory. In October 2026, a series of attacks struck commercial vessels off Romania and Bulgaria, two NATO and European Union members. The western Black Sea had long served as a relatively stable corridor for grain, energy, and general cargo. Those incidents have now made it one of Europe's most dangerous stretches of water for commercial shipping.
Shipowners and captains are pushing back against orders to call at Romanian and Bulgarian ports, citing the rising threat to crews, hulls, and cargo. EU and NATO member states have warned that the worsening violence threatens commercial navigation across the region.
In October, nine cargo vessels were struck or sunk in waters off Romania and Bulgaria. Four went down, two crew members were killed, and 30 seafarers remain listed as missing. Several of the incidents occurred inside Bulgaria's exclusive economic zone or within or just outside Romanian territorial waters.
The pattern is significant for cargo interests. The strikes reached tankers, bulk carriers, general cargo ships, and a container vessel. They also hit approaches to Constanta and the Sulina channel, a key gateway to the Danube. A Constanta-bound container ship sinking in Bulgarian waters shows that liner traffic serving NATO ports is no longer insulated from the conflict.
The escalation has opened a new front in commercial disputes. Shipowners and masters are challenging orders to call at Romanian and Bulgarian ports, arguing that the danger to vessels and crews has risen sharply.
Charter contracts generally require that vessels be sent only to ports that are safe to reach, use, and leave. When conditions change during a voyage or a charter period, owners may refuse or contest orders that would expose ships to risks they did not accept at fixture. Such disputes can leave cargo waiting, voyages suspended, and contracts subject to renegotiation.
For shippers, the immediate effects are higher uncertainty over transit schedules and vessel availability. Cargo bound for or loading at western Black Sea ports faces a greater risk of delay, diversion, or cancellation as owners weigh each call against the threat environment.
The danger extends beyond shipping lanes to critical energy infrastructure. On August 26, a naval drone was spotted just a few hundred meters from Romania's Neptun Deep offshore gas project, prompting Bucharest to scramble F-16 fighter jets to destroy it. Earlier, on August 11, Romanian army divers destroyed two Gerbera-type drones drifting in the country's Black Sea exclusive economic zone near the project.
Neptun Deep is jointly owned by OMV Petrom, which is majority-controlled by Austria's OMV, and Romanian state producer Romgaz. The project is set to make Romania the European Union's largest gas producer next year, which makes its security a matter of regional energy policy as well as a national concern.
Constanta itself has already been touched by the conflict. On June 5, a maritime drone self-detonated in the port near an oil terminal, causing no casualties. Ukraine said the drone belonged to it but that it had lost control of the craft because of Russian electronic warfare jamming.
EU and NATO member states have warned that the worsening violence threatens commercial navigation in the Black Sea. The concentration of attacks off Romania and Bulgaria places alliance coastlines, territorial waters, and economic zones directly in the path of the conflict. The incidents also raise questions about how far maritime security measures can extend to protect merchant traffic.
