The announcement came as the US Secretary of Defense for Policy, Elbridge Colby, began his first overseas visit to Seoul, where he met South Korean Defence Minister Ahn Gyu-back.
The move also signals a US push for South Korea to take on a more prominent role in deterring North Korea, according to Reuters.
On Saturday, the Pentagon, in its 2026 National Defense Strategy, called for a more limited US role in deterring North Korea and urged allies to take on greater burden sharing responsibilities.
In a joint statement, both countries described cooperation on a nuclear powered submarine as a significant step that would strengthen South Korea’s ability to defend the peninsula and reinforce the security alliance in the Indo Pacific region.
The statement said the South Korean side underlined that nuclear powered submarine cooperation would contribute to the alliance with the United States by strengthening Seoul’s deterrence capabilities and stressed the need for concrete implementation through working level talks.
Posting on X, Colby said South Korea was a model ally that had committed to meet the global standard of spending 3.5 percent of GDP on defence and to take greater responsibility for its own defence in line with the National Defense Strategy.
South Korea, a key ally of the United States, hosts around 28,500 US troops. Last year, Seoul pledged to raise its defence spending to 3.5 percent of GDP.
In November 2025, South Korea and the United States signed a trade agreement that included 150 billion dollars in Korean investment in the US shipbuilding sector.
Under the agreement, South Korea is expected to build nuclear powered submarines as part of a new partnership.
Separately, South Korea has also announced plans to build two new nuclear reactors by 2038 amid growing demand for clean energy.
