Closer look at Russian Navy’s giant nuclear submarine vessel K-329 Belgorod

Russia’s K-329 Belgorod ranks among the largest submarines currently in naval service, second only to the Cold War-era Soviet Typhoon-class. It is a nuclear-powered vessel with a rare dual-mission profile that adds a layer of strategic ambiguity to its operations. Equipped with a smaller, nuclear-powered drone submarine for specialized deep-sea tasks, the Belgorod also serves a critical role in Moscow’s underwater nuclear deterrence strategy, deploying Poseidon nuclear-armed torpedoes.

The Belgorod surpasses even the largest submarines in the US Navy, including the Ohio-class ballistic missile subs. It is not only nuclear-armed but also nuclear-powered, placing it in a unique category within Russia’s naval fleet. As noted in an article by 19FortyFive, the Belgorod generated significant attention when it quietly left the dockyard a few years ago.

“Belgorod is one of the least understood submarines currently being built. It was launched in April 2019 and started sea trials on June 25, 2021,” the article cites naval analyst H.I. Sutton.
“It will be armed with the Poseidon strategic nuclear weapon and also perform secretive seabed warfare missions. In this latter role, it will be operated on behalf of the Main Directorate of Deep-Sea Research (GUGI).” The article adds, “It is unclear which role will take precedence.”

Key features separating it from other submarines

Unlike most submarines in the world’s navies, the K-329 Belgorod can carry out two distinct mission sets—only one of which is combat-oriented. The submarine acts as a mothership to a smaller, attached submersible, which is also nuclear-powered and built for specific deep-sea functions.

This smaller sub is likely equipped for extreme-depth operations, including seabed surveillance, mine-laying, and possibly interference with undersea data cables that facilitate global internet and communications traffic.

“The Belgorod submarine opens up new opportunities for Russia in conducting various research, allows conducting diverse scientific expeditions and rescue operations in the most remote areas of the world ocean,” said Russian Navy chief Admiral Nikolai Anatolyevich Yevmenov in a 2022 July statement.

“The ship is designed to solve diverse scientific problems, conduct search and rescue operations, and can also be used as a carrier of rescue deep-sea and autonomous unmanned underwater vehicles.”

Yet while the Belgorod is capable of scientific and clandestine missions, it is also armed with nuclear munitions, reinforcing its status as a strategic weapon platform.

Nuclear deterrence

Despite its non-combat features, the Belgorod remains a formidable attack submarine with nuclear capabilities. It carries up to six Poseidon torpedoes, each armed with a nuclear warhead. These torpedoes are reportedly versatile enough to target both coastal cities and US Navy Carrier Strike Groups.

The Poseidon weapons are not just nuclear-tipped but as the article recalls also nuclear-powered, giving them an almost unlimited range and extraordinary underwater speed. Their potential to outpace virtually all enemy submarines and surface ships adds to their strategic value.

According to the Naval News publication, it is a giant torpedo which has the ability to hit coastal cities with devastating results. While it is very slow compared to an intercontinental ballistic missile, experts believe the weapon is possibly unstoppable. As the article notes, Russia maintains that it can also be used as a tactical nuclear weapon against warships, which would also include high-value targets like aircraft carriers. 

Initial reports suggested the Belgorod would be deployed in the Pacific following trials and commissioning, according to an earlier made Russian Defence Ministry source cited by TASS. Those earlier reports — importantly, released before the 2022 outbreak of the Russia-Ukraine war - indicated Moscow aimed to boost its Arctic presence and assert dominance in the geopolitically sensitive polar region. However, Russia’s intensified focus on the Ukraine conflict may have delayed or deprioritized that mission.

Due to the covert nature of the Belgorod and its operations, many details about the submarine remain undisclosed. Nevertheless, the article recalls that it occupies a highly specialized role in the Russian Navy and is likely one of the Kremlin’s most advanced and secretive undersea assets.

By Nazrin Sadigova