The Republic of Korea (ROK) and the United States have agreed to further deepen cooperation on the development of a nuclear-powered submarine for South Korea.
Elbridge Colby, in his first overseas trip as the U.S. Undersecretary of War for Policy, met with South Korean Defense Minister Ahn Gyu-back in January 2026 to solidify agreements calling for the U.S. to “work closely with the ROK to advance requirements for [the] shipbuilding project, including avenues to source fuel,” according to a White House fact sheet.
Officials from both nations described the arrangement as a strategic partnership that will involve coordination across U.S. agencies and close consultation on technical and nonproliferation issues. “Cooperation on nuclear-powered submarines would strengthen South Korea’s deterrence capabilities and, in turn, contribute to the alliance,” Foreign Minister Cho Hyun said in a news release.
Seoul’s aspirational submarine program is aimed at strengthening its independent deterrent and maritime defense capabilities as part of a broader plan to modernize the Navy and ensure the country can operate more effectively in contested waters around the Korean Peninsula.
Analysts point to the security environment on the peninsula as a primary driver for the move. North Korea’s expanding missile and submarine forces, along with broader strategic competition in the Indo-Pacific, have prompted Seoul and Washington to seek ways to bolster deterrence and interoperability. ROK officials say that nuclear-powered submarines will provide greater range, endurance and stealth than diesel-electric boats.
Further details, including timelines, technical arrangements and industrial partnerships, will be worked out through ongoing consultations and formal agreements.