Ukraine's Security Service, in coordination with the Ukrainian Navy, has carried out a landmark special operation targeting russian submarine in the port of Novorossiysk.
The operation reportedly involved underwater drones known as Sub Sea Baby, which struck russian Project 636.3 submarine of the Varshavyanka class (NATO designation: Kilo-class). The explosion caused critical damage to the vessel, effectively putting it out of action. If confirmed, this would be an unprecedented combat success for unmanned underwater systems against a conventional submarine.
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The targeted submarine was armed with Kalibr cruise missiles, with four launchers on board. These missiles have been repeatedly used by russia to strike Ukrainian cities and infrastructure from the Black Sea. Disabling such a platform therefore has both immediate military value and broader strategic significance, reducing russia's capacity to conduct long-range precision strikes.
The Varshavyanka-class submarines are among russia's most valued non-nuclear naval assets. Often referred to as Black holes due to their low acoustic signature, they are designed to be difficult to detect by sonar and are central to russia's undersea warfare doctrine in the Black Sea. Their vulnerability to Ukrainian drones challenges long-standing assumptions about their survivability in coastal and port environments.
Financially, the loss is substantial. A single Varshavyanka-class submarine is estimated to cost around $400 million, and under current international sanctions, replacing such a vessel could push the price closer to $500 million. For russia, this represents not only a material loss but also an industrial and logistical setback at a time when its defense sector is under sustained pressure.
The operation was conducted jointly by the 13th Main Directorate of the Security Service Military Counterintelligence and the Ukrainian Navy, highlighting an increasingly integrated approach to asymmetric warfare at sea. Ukraine continues to compensate for its lack of a traditional large navy by investing in innovative drone technologies and precise special operations.
Notably, the damaged submarine was in Novorossiysk because russian naval forces had already been forced to relocate from Sevastopol, in temporarily occupied Crimea. Earlier successful attacks by Ukrainian surface maritime drones, also known as Sea Baby, made the Crimean port increasingly unsafe for russian ships and submarines, pushing them farther east along the Black Sea coast.
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