NATO warships have not sailed into the Black Sea on a rotating basis since 2022. The reason is a 1936 treaty, the Montreux Convention, which Turkey enforces to the letter. Yet the alliance’s weight in the region keeps growing, according to an analysis published by the Carnegie Endowment for International Peace, which describes a quiet “NATO-ization” of the sea carried out on land and in the air.
The alliance’s July 7-8 summit in Ankara made the point. Turkey, Romania and Bulgaria are upgrading their fleets and building closer three-way ties, and the summit showed NATO more involved in the area than before.
Ships out, troops and aircraft in
Even the Sea Breeze exercise, long co-led by the United States and Ukraine with NATO participation, now takes place far from the Black Sea. In 2025 it was held off the south coast of the UK, where four Ukrainian mine hunters based in Portsmouth took part: Chernihiv and Cherkasy, donated by the Royal Navy, Mariupol, from Belgium, and Melitopol, from the Netherlands.
Carnegie notes that the closed sea cuts both ways. It has also kept Russia from reinforcing its own Black Sea Fleet.
On land, NATO placed multinational brigades in Romania and Bulgaria in 2022, led by France and Italy respectively. The UK, France and Belgium ran a joint air-policing surveillance exercise over the sea in July 2025. Mihail Kogălniceanu Air Base, beside the Romanian port of Constanța, has become a main operational and logistics hub on the alliance’s eastern flank. Greece, Bulgaria and Romania have also set up a rail supply corridor along the coast to move matériel to Ukraine.
Three navies rebuilding
Turkey commissioned TCG Istanbul in January 2024, the first of ten multirole frigates built domestically under its MILGEM program. Indonesia signed for two of the ships last year. In July 2026, Romania took delivery of a MILGEM patrol vessel, Contraamiral Roman, fitted with Norwegian naval strike missiles. The contract was worth €223 million ($255 million). Romania’s military also has a contract with the Turkish firm Otokar for 1,059 Cobra II armored vehicles.
Bucharest plans four more vessels, two of them to light-corvette standard, funded through the EU’s Security Action for Europe instrument, which allocates €8.3 billion ($9.5 billion) to Romanian projects. Germany’s Rheinmetall is the partner. The plan fills a hole left when a €1.2 billion ($1.4 billion) deal with France’s Naval Group, covering four Gowind-class corvettes, fell apart. Romania aims to lift defense spending from 2.24 percent of GDP to 3 percent by the next decade.
Bulgaria’s navy has started sea trials for the corvette Hrabri, the first of two designed by Germany’s NVL Group and built in Varna. Its sister ship Smeli was launched in December 2025. Belgium and the Netherlands handed Bulgaria seven mine countermeasure ships free, in return for a pledge to train Ukrainian crews.
The three navies work together on the water as well. In July 2024 their chiefs, Ercüment Tatlıoğlu, Mihai Panait and Kiril Mihaylov, started a joint mine-clearance operation. Since fall 2023, Ukrainian ships have stuck to Romanian, Bulgarian or Turkish territorial waters, and an estimated 90 percent of Kyiv’s agricultural exports depend on those routes.
Ukraine’s side of the ledger
Carnegie credits Ukraine’s sea and air drones, among them the Magura V5 and Sea Baby, with tipping the military balance over the last three years. Reported attacks reached 125 in 2024, and the Russian Black Sea Fleet moved from Sevastopol to Novorossiysk. Kyiv began hitting Russian commercial vessels, including shadow-fleet tankers, in November 2025. This year its drones have gone after oil facilities around Novorossiysk and Kerch, with fuel shortages in Crimea as a result.
The Russian fleet is still dangerous. Kalibr cruise missiles launched from ships and submarines turn up periodically in combined strikes on Ukraine. A Russian drone hit a Turkish cargo ship sailing under a Panamanian flag on June 22, and another strayed into a residential building in Galați, Romania, in late May.
Turkey, for its part, wants a seat in any settlement. It is ready to lead the naval part of a multinational force after a ceasefire, and a command center has already been set up in Istanbul’s Beykoz district.
