Ukrainian Sub Sea Baby UUV targets Russian ‘Kilo’-class submarine at Novorossiysk
Peter Felstead
The Security Service of Ukraine (SSU) announced on 15 December 2025 another unique special operation against Russian forces carried out that day, this time using for the first time a bomb-laden Sub Sea Baby unmanned underwater vehicle (UUV) to attack the Russian Project 636 Improved ‘Kilo’-class submarine Varshavianka in the naval base at Novorossiysk.
Video footage on the SSU website, which appears to have been taken in daylight from the shore area above Novorossiysk naval base (most likely from a vantage point along the M-4 highway that runs northwest/southeast north of the base), shows a significant explosion as the submarine is attacked to the stern.
“As a result of the explosion, the submarine suffered critical damage and was effectively put out of action,” the SSU stated, adding that the ‘Kilo’-class boat features “four launchers for Kalibr cruise missiles, which Russia has used to strike Ukrainian territory.”
The SSU added that the attack was a joint operation of the 13th Main Directorate of the SSU Military Counterintelligence and the Ukrainian Navy.
“The submarine had been forced to stay in the port of Novorossiysk due to successful special operations by the SSU’s Sea Baby surface drones, which drove the enemy fleet out of Sevastopol Bay in the temporarily occupied Crimea,” the SSU stated.
Little is known about Ukraine’s Sub Sea Baby UUV. Although its nomenclature might suggest it is a development of the Sea Baby uncrewed surface vessel (USV), it is more likely to be a newly developed UUV with its own design characteristics.
The attack on Varshavianka is the second time a Project 636 ‘Kilo’-class submarine has been targeted by Ukraine, after the submarine Rostov-on-Don was severely damaged by a combined missile and USV attack on Sevastopol in September 2023.
A 16 December report by Russia’s state-owned Zvezda TV network, which is run by the Russian Ministry of Defence, drawing from a Black Sea Fleet press service report, purported to show video footage an undamaged submarine in Novorossiysk Bay. While acknowledging the attack, the report claimed that “not a single ship or submarine stationed in the Novorossiysk Naval Base Bay, nor their crews, were damaged as a result of the sabotage”. However, the video did not appear to show the stern of the submarine where it was targeted.
