Security Service of Ukraine/Screengrab via Telegram
Ukraine says it has crossed a new threshold in modern warfare by using an underwater drone to strike a Russian submarine, marking what Kyiv describes as the first-ever attack of its kind. The operation signals a major escalation in how uncrewed systems are being used at sea and beneath it, as reported by The War Zone.
According to Ukraine’s Security Service, known as the SBU, the attack targeted a Russian Kilo-class diesel-electric submarine at the Black Sea port of Novorossiysk. The agency described the mission as a “unique special operation” carried out using an underwater drone packed with explosives. The strike reportedly damaged and disabled the submarine, which the SBU said was equipped with four launchers for Kalibr cruise missiles, weapons Russia has repeatedly used to attack Ukrainian cities.
The underwater drone used in the attack is called the Sub Sea Baby, which appears to be a submerged counterpart to Ukraine’s well-known Sea Baby naval drones. Those surface drones have already played a major role in damaging Russian warships and port infrastructure across the Black Sea. This latest operation suggests Ukraine has now extended that concept below the waterline.
The SBU did not disclose the exact date of the attack but said it was conducted in coordination with the Ukrainian navy. It also released footage that appears to show the moment the drone hit the submarine, triggering a large explosion. Neither Russia’s defense ministry nor its US embassy immediately commented on the claim.
Kilo-class submarines have been a backbone of Russia’s undersea fleet since the 1980s. They are relatively quiet, diesel-electric boats designed for coastal and regional operations, and Russia operates dozens of them. The SBU estimates the cost of a single Kilo-class submarine at around $400 million, adding that international sanctions would likely make replacing a damaged boat far more expensive and time-consuming.
The strike fits into Ukraine’s broader campaign against Russia’s Black Sea Fleet. Since the start of the war, Ukraine has relied on an asymmetrical strategy, using missiles and drones to hit ships that far outmatch it on paper. That pressure forced Russia to move much of its fleet from its longtime base in occupied Crimea to Novorossiysk. Ukraine has since demonstrated that even this relocation does not guarantee safety.
More importantly, the attack may represent a new phase in drone warfare. Ukraine has already used underwater drones to target Russia’s so-called shadow fleet of oil tankers and naval drones to strike surface ships. Using an underwater drone to attack a submarine suggests capabilities that resemble a low-cost, slow-moving mine or torpedo, but without the need for a traditional navy.
The implications extend beyond Ukraine. Russia, NATO members, and other military powers are investing heavily in underwater drone technology as a way to complement or eventually replace some traditional naval assets. If Ukraine’s claims are accurate, this operation could be remembered as a turning point, showing how relatively inexpensive uncrewed systems can threaten even some of the most complex and costly platforms in modern naval warfare.
