In a major development in the Ukraine-Russia war, Ukraine has claimed to have destroyed a Russian Kilo-class submarine using its domestically produced unmanned underwater drone, named “Sub Sea Baby.” The attack reportedly took place at the Novorossiysk port, a key Russian naval base on the Black Sea. Ukraine’s security services stated on Monday that the submarine suffered severe damage and is now completely inoperable. The vessel was capable of carrying Kaliber cruise missiles, which have frequently been used against Ukrainian targets.
Wow, wow, wow. 🔥🔥🔥
For the first time in its history, Ukraine has sunk a Russian submarine with Sub Sea Baby underwater drones in Novorossiysk.
The Security Service of Ukraine (SBU) conducted a unique naval special operation in the port of Novorossiysk. The Sub Sea Baby… pic.twitter.com/gshAcZ331L
— Jürgen Nauditt 🇩🇪🇺🇦 (@jurgen_nauditt) December 15, 2025
An advisor to Ukrainian President Volodymyr Zelensky noted on Twitter that this marks the first time in naval history that a submarine has been targeted by a water-level drone. Ukraine also released video footage of the explosion caused by the strike, showcasing the capabilities of its unmanned underwater systems. The development is seen as a demonstration of Ukraine’s evolving naval strategy against a superior Russian fleet.
The Russian Black Sea Fleet, however, denied the claims, stating that none of their ships or submarines at the Novorossiysk base were damaged and that all vessels remain fully operational. The Russian Ministry of Defence emphasized that the fleet continues to carry out its duties without disruption.
Analysts highlight that Ukraine, with relatively limited conventional naval power, is increasingly relying on surface and underwater drones to challenge Russia’s dominant presence in the Black Sea. If verified, the successful deployment of an unmanned underwater drone against a submarine could mark a significant shift in naval warfare, potentially influencing global military strategies.