The 2018 Kerch Strait Attack and Capture of Ukrainian Sailors
On November 25, 2018, two small Ukrainian armored artillery boats and a naval tug approached the Kerch Strait on a voyage from Odesa to Mariupol. By nightfall, Russian forces had fired on them, seized all three vessels, and detained 24 sailors.
Unlike the deniable warfare that marked much of Donbas, the confrontation involved vessels openly serving the Russian and Ukrainian states. It moved their conflict directly into the maritime domain.
The Attempted Passage
The Berdyansk, Nikopol, and tug Yani Kapu planned to join Ukraine's growing naval presence in the Sea of Azov. A previous Ukrainian naval group had passed through the strait in September, but relations around the new Kerch Bridge had grown more restrictive.
Russia and Ukraine disputed the rules governing the voyage. Ukraine relied on navigational rights, the immunity of naval vessels, and a 2003 bilateral treaty describing the Sea of Azov and Kerch Strait as historically internal waters shared by both countries.
Russia said the vessels entered waters it considered Russian, ignored orders to stop, and failed to follow required advance procedures. Ukraine said it had given notice, had a right of passage, and could not be made to recognize Russian sovereignty over occupied Crimea or adjacent waters.
The sovereignty dispute sat underneath the procedural one. Russia treated waters off Crimea as belonging to it after annexation, while Ukraine and most other states continued to treat Crimea and its territorial sea as Ukrainian.
Blocking, Pursuit, and Gunfire
Russian coast-guard vessels intercepted the group before the bridge and rammed the Yani Kapu during hours of maneuvering. A large civilian ship was placed beneath the bridge's arch, physically closing the only passage into the Sea of Azov.
Radio exchanges and Russian video later documented warnings, orders, and the pursuit from the perspective of the coast guard. Ukraine released its own communications and tracking information, producing two incompatible legal accounts but no dispute that Russian state vessels controlled the encounter.
The Ukrainian vessels eventually turned south, away from the strait. Russian forces pursued them in the Black Sea, fired on the Berdyansk, wounded three crew members, boarded the vessels, and took every sailor into custody.
Russia transferred the crews to detention in occupied Crimea and then Moscow, treating them as criminal suspects accused of crossing its border illegally. Ukraine considered them prisoners of war and demanded their immediate release.
International and Legal Responses
Ukraine introduced 30 days of martial law in ten regions considered vulnerable to Russian attack, while avoiding a national suspension of elections or civilian government. NATO, the European Union, and many governments called on Russia to release the sailors and restore unhindered passage.
The limited duration and geography reflected political caution before Ukraine's 2019 presidential election. Kyiv raised military readiness without giving the government an open-ended emergency or delaying the scheduled vote.
Ukraine also began proceedings under the UN Convention on the Law of the Sea. In May 2019, the International Tribunal for the Law of the Sea ordered provisional measures requiring Russia to release the vessels and sailors while the wider case proceeded.
The tribunal did not decide the final merits of the competing maritime claims. Russia rejected its jurisdiction by characterizing the incident as a military activity covered by both states' legal reservations and did not participate in the hearing.
The order recorded facts that weren't disputed: the three craft were Ukrainian naval vessels, their crews were military personnel, Russian forces seized them, and Russian fire wounded three men. Those points narrowed the space for portraying the incident as an encounter with unidentified actors.
Release Without Resolution
The sailors returned to Ukraine in a 35-for-35 exchange with Russia on September 7, 2019. Russia returned the stripped and damaged vessels that November, but the underlying dispute over passage, occupation, and maritime control remained.
The exchange became an early diplomatic success for Ukraine's newly elected president. Volodymyr Zelenskyy hoped practical steps like bringing detainees home could build toward a broader effort to end the Donbas war.
Crimea After Annexation: Militarization and the Kerch Bridge
Zelenskyy's Attempt to End the Donbas War