South Korea’s Ministry of National Defense (MND) has formally unveiled plans to develop and build a domestically produced, nuclear-powered submarine by the mid-2030s, marking a major step in Seoul’s efforts to strengthen persistent undersea surveillance of North Korea.
Under the programme, dubbed Jang Bogo-N, the nuclear-powered submarines (SSN) will use low-enriched uranium fuel designed for long operational cycles, therefore reducing the frequency of refuelling.
The ministry said the boats would be designed and constructed entirely within South Korea, leveraging decades of experience from the country’s civilian nuclear energy and commercial shipbuilding industries to ensure high reliability and safety standards.
Officials also emphasised that domestic construction would provide “independence and stability in acquisition, sustainment and maintenance” throughout the programme’s lifecycle.
The announcement differs from remarks made in late 2025, when US President Donald Trump indicated that future South Korean SSNs could be constructed at Hanwha Ocean’s newly acquired Philly Shipyard in Philadelphia, following Washington’s in-principle approval for Seoul to pursue the capability.
South Korea now aims to launch the lead submarine in the mid-2030s, with operational deployment expected in the latter part of that decade.
According to the MND, the submarines will provide extended endurance for tracking North Korean naval activity, and also form part of an underwater “kill chain” capable of supporting precision strike operations in the event of conflict.
South Korea’s existing Dosan Ahn Changho-class KSS-III diesel-electric submarines are uniquely equipped with vertical launch systems capable of firing conventionally armed Hyunmoo-4-4 ballistic missiles. Similar capabilities are expected to feature on the future SSNs as well.
Meanwhile, Seoul continues to promote its submarine industry overseas.
As part of South Korea’s campaign to sell the KSS-III to Canada, the submarine ROKS Dosan Ahn Changho recently completed a 14,000km endurance deployment from South Korea to Canadian Forces Base Esquimalt near Victoria, British Columbia.
Two Royal Canadian Navy submariners embarked the boat in Hawaii for the onward transit to observe operations during the voyage.
The submarine was accompanied by the frigate ROKS Daejeon, with both vessels scheduled to conduct subsequent exercises with the Royal Canadian Navy.
by Chen Chuanren
