Ukraine’s Security Service (SBU) says it struck a Russian submarine in the port of Novorossiysk that was armed with Kalibr cruise missiles, following a unique special operation using underwater drones.
The SBU says Ukrainian forces conducted another precision strike deep inside Russian territory, detonating a Russian submarine directly in the waters of Novorossiysk port. According to the agency, Sub Sea Baby underwater drones successfully attacked a Russian submarine for the first time in modern warfare.
The target was a Project 636.3 diesel-electric submarine of the “Varshavyanka” class, known in NATO classification as Kilo. A powerful blast inflicted critical damage that rendered the vessel unusable, the SBU said.
The agency noted the hit submarine carried four launchers for Kalibr cruise missiles—the type Russia regularly uses in strikes across Ukraine, including on cities and civilian infrastructure.
The operation was conducted jointly by the SBU’s 13th Main Directorate of Military Counterintelligence and the Ukrainian Navy, which the agency says has increased pressure on Russia’s naval posture in the Black Sea region.
According to Ukrainian estimates, a Varshavyanka-class submarine costs about $400 million. With sanctions and limited access to technology, building a comparable new vessel for Russia could cost up to $500 million. These submarines are informally dubbed “Black Hole” for their ability to absorb noise and remain difficult to detect by sonar.
The SBU added the submarine was in Novorossiysk not by choice. Earlier, a series of successful attacks by Ukrainian Sea Baby surface drones forced Russia’s fleet to move ships and submarines out of Sevastopol Bay in occupied Crimea to seek safer bases.
Recently, long-range drones from the SBU’s Alpha special unit struck deep into Russian territory, hitting an oil production platform in the Caspian Sea.
Earlier, Sea Baby marine drones hit the Dashan oil tanker, which was transiting Ukraine’s exclusive economic zone toward the Novorossiysk port terminal with its transponder switched off.
