South Korea will domestically develop and build a nuclear-powered submarine with a targeted launch in the mid-2030s [1].

The initiative represents a significant escalation in South Korea's naval capabilities. By deploying nuclear-powered vessels, Seoul aims to increase its underwater endurance and stealth to better counter the nuclear and missile threats posed by North Korea.

President Lee Jae-myung announced the plan on May 26 during the first Future Defense Strategy Committee meeting in Seoul [1, 2]. Lee said the project is a symbol of the nation's will to take responsibility for peace and security on the Korean Peninsula [1].

The project follows a U.S.-South Korea summit in October 2025, where approval for the program was granted [1]. To maintain international safeguards, the submarines will use low-enriched uranium at levels below 20% [1].

International regulators have raised concerns regarding the oversight of nuclear materials. Rafael Grossi, the Director General of the IAEA, said in mid-May that thorough verification is required to ensure large quantities of nuclear material do not fall outside the agency's inspection network [3].

U.S. officials have indicated that the administrative process is moving forward. Thomas Dinano, the U.S. Deputy Secretary of State for Arms Control and International Security, said that extensive procedures are currently underway [2].

While the South Korean government intends to build the vessels domestically [2], some reports have indicated differing views on whether construction would occur in the U.S. [1]. The South Korean government maintains that operational deployment will follow the initial launch in the late-2030s [1, 2].

“A symbol of the nation's will to take responsibility for peace and security on the Korean Peninsula”

The transition to nuclear-powered submarines allows South Korea to maintain a persistent presence in contested waters without the frequent surfacing required by diesel-electric boats. This shift signals a move toward strategic autonomy in defense, provided the U.S. continues to support the fuel enrichment and technology transfers necessary to bypass traditional non-proliferation hurdles.