Russia’s Purpose-Built Poseidon Carrier, Project 09851 Khabarovsk, Commences Sea Trials

After over a decade of development, Russia’s Project 09851 nuclear submarine, Khabarovsk, has embarked on its inaugural factory sea trials. This specialized vessel is designed to deploy the formidable Poseidon nuclear-powered unmanned underwater vehicles (UUVs), marking a significant milestone in Russia’s strategic naval capabilities.

The Khabarovsk departed from Severodvinsk on August 17, initiating a series of rigorous tests from the Sevmash Shipyard, where it was constructed. These initial trials will meticulously assess the submarine’s propulsion system, navigational performance, and the operational integrity of its various onboard systems.

The submarine is equipped with six 2P39 launch tubes specifically designed for the Poseidon UUVs. While its primary mission as a Poseidon carrier is known, the full complement of Poseidon units it will carry and other comprehensive technical specifications of the Khabarovsk remain undisclosed by Russian authorities.

Designed by Russia’s renowned Rubin Central Design Bureau for Marine Engineering, the contract for the Khabarovsk was sealed with the Russian Ministry of Defense on June 19, 2012. Construction at Sevmash Shipyard commenced on July 27, 2014, and the submarine was floated out from its enclosed construction hall on November 1, 2025. Although earlier reports from the Rubin Design Bureau indicated a planned delivery to the Russian Navy in 2020, the vessel’s factory sea trials only began in August 2026, representing an approximate six-year delay. No public explanation for this protracted timeline has been provided. Upon completion of these trials, the Khabarovsk is expected to join Russia’s Pacific Fleet.

The Khabarovsk follows the Project 09852 BS-329 Belgorod special-purpose nuclear submarine, which entered service on July 8, 2022, as Russia’s first Poseidon carrier. However, unlike the Belgorod, which was converted from the hull of an unfinished Project 949A nuclear-powered cruise missile submarine, the Khabarovsk represents the first submarine specifically designed from the keel up to host the Poseidon system. The Belgorod is outfitted with four 2P39 launch tubes for the Poseidon UUVs. Furthermore, the Rubin Design Bureau had announced plans in 2016 to work on Project 09853, believed to be a follow-on or serial production variant of the Khabarovsk class.

The Poseidon is conceptualized as an intercontinental-range, nuclear-powered autonomous underwater vehicle, capable of delivering a nuclear warhead. Its design emphasizes stealth and deep-ocean capabilities, presenting a unique strategic deterrent. Russian President Vladimir Putin confirmed on October 29, 2025, that a test involving the Poseidon’s nuclear propulsion system had been successfully conducted. During this trial, the Poseidon was reportedly launched from its carrier submarine, and its nuclear power unit was activated and operated for a specified duration.

To support the deployment of Poseidon-carrying submarines, Russia is also constructing a dedicated submarine base in Krasheninnikov Bay on the Kamchatka Peninsula. This facility is planned to provide comprehensive logistical and technical support for both the Khabarovsk and Belgorod, alongside Project 20183 class support vessels.

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