Everything we know about North Korea's nuclear-powered submarine

Independent

11-03-2025

North Korea 's nuclear-powered submarine, believed to be built with Russian technology, could pose major security concerns to neighbour South Korea and its ally, the US, due to its capabilities, experts say.
North Korea for the first time on Saturday unveiled the photos of what it called an under-construction"nuclear-powered strategic guided missile submarine", according to state media Korean Central News Agency.
A nuclear-powered submarine was among the long wishlist of sophisticated weaponry that the North's leader Kim Jong Un had vowed to introduce during a major political conference in 2021 to tackle US-led "military threats".
During the inspection of the submarine, Mr Kim warned that Pyongyan would never tolerate "maritime and underwater military activities of the hostile forces, which seriously threaten the country's sovereignty and interests through the constant deployment of strategic assets".
'Overwhelmingly powerful warships must serve as a strong nuclear deterrent against hostile forces' habitual 'gunboat diplomacy'," he added, according to state-media Rodong Sinmun.
Photos of the submarine were tactically released just two days before South Korea and the US kicked off their annual 'Freedom Shield 2025' drills, which will run through 20 March.
Features of the submarine:
The photos released by the state media on Saturday partially revealed only the lower hull of the large vessel and 15 rail-based cradle stands.
The unnamed naval vessel appears to be a 6,000-tonne-class or 7,000-tonne-class, one which can carry about 10 missiles, said Moon Keun-sik, a South Korean submarine expert who teaches at Seoul's Hanyang University. He said the use of the term "the strategic guided missiles" meant it would carry nuclear-capable weapons.
The vessel appears to be docked at the Chongjin Shipyard and is at least 117m long, according to NK News.
The submarine is likely twice the size of Hero Kim Kun Ok – the North's first ballistic missile submarine revealed in 2023. Pyongyang already has an estimated 70-90 diesel-powered submarines in one of the world's largest fleets. However, they are mostly aging vessels capable of launching only torpedoes and mines, not missiles.
North Korea has conducted a slew of underwater-launched ballistic missile tests since 2016, but all launches were made from the same 2,000-tonne-class submarine which has a single launch tube. Many experts call it a test platform, rather than an operational submarine in active service.
Use of Russian technology
Questions about how North Korea, a heavily sanctioned and impoverished country, could get resources and technology to build nuclear-powered submarines have surfaced.
Experts believe the North may have received Russian technological assistance to build a nuclear reactor to be used in the submarine in return for supplying conventional weapons and troops to support Russia's war efforts against Ukraine. About 12,000 North Korean troops are already fighting for Russia in Moscow's war against Kyiv, according to South Korea's spy agency.
Given the size and shape of the submarine, it's believed to be a ballistic missile submarine (SSBN), said Yang Uk, a defence expert and research fellow at Asan Institute for Policy Studies.
He told the Korea Times that the photos suggest the submarine has been under construction for more than two years. North Korea may have received technology from Russia in the latter half of 2023, he added.
When will the submarine be deployed?
The North could take "at least four to five more years to deploy the submarine into the Pacific Ocean" as it still needs to conduct more procedures including testing, experts believe.
However, if the North has indeed received assistance from Moscow in developing compact nuclear reactors capable of withstanding deep-sea pressure, the vessel could be deployed faster.
Pyongyang may also intend to deploy the ships to international waters beyond the 12-nautical-mile limit of a country's territorial sea.
What are North Korea's opponents saying?
The North Korea has been dialling up its fiery rhetoric against the US and South Korea ahead of their annual military drills, which will involve responsed to evolving challenges like Pyongyang's growing partnership with Moscow.
Pyongyang obtaining a greater ability to fire missiles from underwater is a worrying development because it is difficult for its rivals to detect such launches in advance.
During his visits to the shipyards, Mr Kim said North Korea aims to modernise water-surface and underwater warships simultaneously. He stressed the need to make "the incomparably overwhelming warships fulfil their mission" to contain "the inveterate gunboat diplomacy of the hostile forces".
South Korea's ministry of unification said it is closely monitoring any signs of Russia's transfer of technologies to North Korea. 'The transfer of military technology to North Korea is prohibited under UN Security Council resolutions. Russia, as a permanent member of the UN Security Council, must abide by UN sanctions on North Korea,' unification ministry spokesperson Koo Byung Sam told reporters.
US National Security Council spokesperson Brian Hughes said: "We're aware of these claims and do not have additional information to provide at this time. "The US is committed to the complete denuclearisation of North Korea."