Ukraine Claims Historic Underwater Strike on Russian Submarine as Moscow Denies Damage
Ukraine says it has carried out a landmark naval strike inside a major Russian Black Sea base, using an underwater drone to hit a missile-capable submarine docked at Novorossiysk, a claim Russia flatly rejects. According to Ukraine’s Security Service (SBU), the December 15 operation targeted an Improved Kilo-class diesel-electric submarine, one of Russia’s most valuable naval assets in the region. The SBU described the attack as a joint operation with Ukrainian naval forces and said it used a new unmanned underwater vehicle known as “Sub Sea Baby.”
The SBU said the submarine suffered critical damage and was no longer capable of carrying out combat missions. Russia’s Ministry of Defense disputed the claim, saying the attack failed and that no vessels inside the Novorossiysk naval base were damaged. Russian officials said all ships and submarines of the Black Sea Fleet remain operational. Independent confirmation of the submarine’s condition remains limited, but publicly released footage from Ukraine shows a large explosion near the stern of a submarine moored inside the base.
What Is Known and What Isn’t
Available evidence establishes several key facts while leaving major questions unanswered.
What can be verified:
Ukraine released video footage showing a powerful blast at a submarine berth inside Novorossiysk.
The location of the footage has been independently verified by multiple international outlets.
The target was an Improved Kilo-class submarine, a platform used by Russia to launch Kalibr cruise missiles against Ukrainian infrastructure.
What remains unconfirmed:
Whether the submarine sank at its mooring.
The full extent of internal damage to the hull, propulsion system, or control surfaces.
How long the vessel, if damaged, would be out of service.
Naval analysts note that even non-catastrophic damage to a submarine can sideline it for months, particularly if pressure hull integrity or propulsion components are compromised.
The “Sub Sea Baby” and a Shift in Naval Warfare
Ukraine says the strike employed a submerged unmanned underwater vehicle rather than the surface drones it has used successfully since 2022. Unlike surface drones, an underwater vehicle can evade many of the floating barriers and boom systems Russia has installed to protect key ports. Ukrainian officials have not disclosed whether the drone was fully autonomous or received external guidance during the attack. However, the ability to navigate confined harbor spaces suggests a significant leap in Ukraine’s maritime strike capabilities. If confirmed, the attack would represent one of the first known uses of an underwater drone to strike a submarine inside a fortified naval base during an active war.
A Broader Black Sea Escalation
The strike comes amid renewed escalation in the Black Sea, following months in which maritime combat had largely shifted to long-range drone and missile attacks. Ukraine has recently intensified strikes on vessels linked to Russia’s so-called shadow fleet, which transports oil in circumvention of sanctions. Russia, in turn, has expanded drone and missile attacks on Ukrainian ports, including strikes on commercial shipping near Odesa.
According to Ukrainian intelligence, the submarine targeted at Novorossiysk was capable of carrying Kalibr cruise missiles, weapons Russia has repeatedly used to hit power grids, ports, and civilian infrastructure. Whether the submarine was preparing an imminent strike is unknown. What is clear is that Ukraine is now aiming beyond disruption at sea lanes and energy exports and directly at Russia’s remaining naval strike platforms.
Why This Matters
Even without definitive proof that the submarine was destroyed, the implications are significant.
Novorossiysk has been one of Russia’s safest fallback bases after repeated Ukrainian strikes forced much of the Black Sea Fleet away from Crimea.
Demonstrating the ability to penetrate that base undermines Russia’s claim of secure rear-area operations.
Each damaged or sidelined submarine reduces Russia’s ability to launch long-range cruise missile attacks from the sea.
From a broader perspective, the strike fits a pattern: Ukraine compensating for its lack of a traditional navy with asymmetric, technology-driven attacks that steadily shrink Russia’s operational space. The deeper message is not just about one submarine, but about whether any Russian port in the Black Sea can still be considered safe.
