On October 30, 2025, President Donald Trump announced the approval for South Korea to construct a nuclear-powered submarine, marking a dramatic move that would position Seoul as one of the few countries with such advanced technology. The decision came following Trump’s visit to South Korea and his meeting with President Lee Jae-myung.
Trump took to Truth Social to announce the news, emphasizing the approval for South Korea to build a nuclear-powered submarine, stating it would not be the outdated, less flexible diesel submarines they currently possess. The technology of nuclear submarines is considered one of the highly protected sensitive technologies within the military domain, with the United States having shared it only with the United Kingdom in the 1950s.
Most recently, the US, UK, and Australia reached an agreement to assist Australia in acquiring nuclear-powered submarines, without directly transferring the design knowledge from the US. Trump further revealed that South Korea had agreed to pay $350 billion to the US in exchange for reduced import tariffs on Korean goods, along with substantial purchases of American oil and natural gas.
South Korea, boasting a mature shipbuilding industry, pledged $150 billion as part of the “Making American Shipbuilding Great Again” (MASGA) investment project. The plan includes rebuilding America’s shipbuilding capabilities.
Notably, the approval for the nuclear submarine is part of a broader range of agreements reached during the US-South Korea summit. Lee emphasized plans to increase military spending to modernize the US-South Korea alliance and ease the financial burden on the US.
The summit was described by Kim Dong-yup, a North Korea expert at Kyungnam University, as a mechanism of “trade-offs between security guarantees and economic contributions”, allowing South Korea to increase defense spending and American investments in exchange for nuclear-powered submarines.
Apart from the nuclear-powered submarine, Lee has been seeking US approval for South Korea to reprocess nuclear fuel. The approval for the nuclear submarine, a departure from the US’s historical opposition, has raised concerns among some experts. Daryl Kimball from the Arms Control Association expressed various doubts regarding South Korea obtaining nuclear submarines, suggesting a need for a new complex safeguard mechanism by the IAEA.
Speculations indicate that South Korea might be seeking highly enriched uranium, similar to the AUKUS agreement, potentially raising concerns about the proliferation of nuclear technologies. The announcement comes amidst escalating regional tensions, with North Korea’s revelation earlier this year of a nuclear-powered submarine under construction posing significant security threats to South Korea and the US.
Jenny Town from the Washington-based organization “38 North” noted that allegations of Russian assistance to North Korea in developing nuclear-powered submarines would likely propel South Korea to seek deeper cooperation with the US on nuclear issues.