The United States will provide South Korea with advanced technology to help it build a nuclear-powered submarine, President Donald Trump announced Thursday on social media following his meeting with South Korean President Lee Jae Myung.
During their talks on Wednesday, President Lee emphasized the need to modernize the U.S.-South Korea alliance, noting plans to boost Seoul’s defense spending to ease Washington’s financial burden.
Lee clarified that there had been some misunderstanding in their previous conversation in August, saying that South Korea was seeking nuclear fuel for submarine propulsion, not nuclear weapons.
He explained that South Korea’s current diesel-powered submarines are limited in tracking other nations’ undersea operations, while nuclear-powered submarines could strengthen both South Korea’s defense and U.S. military efforts in the region.
Unlike diesel-powered submarines that must surface often to recharge batteries, nuclear-powered ones can remain underwater for extended periods, offering greater endurance and stealth.
Trump added in a separate post that the submarine would be built at the Philly Shipyard, which was acquired last year by South Korea’s Hanwha Group.
Details about the project’s scale and cost were not immediately clear, but South Korea has pledged to invest $150 billion in U.S. shipbuilding facilities as part of ongoing defense cooperation.
U.S. nuclear submarine technology is among the country’s most closely guarded military secrets. Even under the AUKUS partnership with the United Kingdom and Australia, Washington has avoided directly transferring such sensitive know-how.
Trump’s announcement comes ahead of his planned meeting with Chinese President Xi Jinping, whose country operates nuclear submarines, and months after North Korea revealed its own nuclear-powered submarine under construction — a development seen as a potential threat to both Seoul and Washington.
Meanwhile, as Trump visited South Korea, Pyongyang said Wednesday it had successfully test-fired new cruise missiles, underscoring its growing military strength.
Pentagon officials have yet to comment on Trump’s statement about sharing nuclear submarine technology with Seoul.
