The move is a significant shift in U.S. policy on exporting guarded nuclear submarine technology.
President Donald Trump shakes hands with South Korean President Lee Jae Myung as he receives a gift of a gold crown and an award of the Grand Order of Mugunghwa, not seen, during a high honor ceremony at the Gyeongju National Museum in Gyeongju, South Korea on Oct. 29, 2025. AP Photo/Mark Schiefelbein
U.S. President Donald Trump announced Thursday that the United States will share sensitive nuclear propulsion technology with South Korea so that the U.S. ally can build a nuclear-powered submarine to counter regional threats, such as from China and North Korea.
The announcement was made via posts by Trump to Truth Social after a Wednesday summit with South Korean President Lee Jae Myung. In addition to the nuclear technology sharing, leaders discussed modernizing their military alliance and trade deals.
South Korea has committed $150 billion to U.S. shipbuilding investments, with the submarine slated for construction at the Philly Shipyard, which is owned by South Korean conglomerate Hanwha Group.
“Our Military Alliance is stronger than ever before and, based on that, I have given them approval to build a Nuclear Powered Submarine, rather than the old fashioned, and far less nimble, diesel powered Submarines that they have now. A great trip, with a great President of South Korea!” Trump wrote on Truth Social.
The move is a major development for Indo-Pacific security, as Seoul can now construct its first nuclear-powered submarine.
Trump met with Lee in Gyeongju, where discussions revolved around increasing defense capabilities and economic cooperation.
As South Korea faces ongoing threats from North Korea’s developing nuclear and missile programs, experts have been debating whether or not the country should arm itself with nuclear weapons. The country can now benefit from nuclear-powered submarines, which have better underwater endurance for longer patrols tracking adversarial vessels without having to regularly surface, as in the case of diesel-powered models.
Although Trump has historically sought diplomacy with North Korea, a major military conflict with the country is still possible, the president said during his first term.
The move represents a departure from Washington’s strict controls on nuclear propulsion technology, previously shared only with close allies such as those in the AUKUS pact, of which Australia and the United Kingdom are a part. Trump, however, has downplayed the strategic importance of AUKUS, saying U.S. military might is enough to counter any threats from China.
South Korea has made some commitments in order to offset U.S. defense burdens, Trump said.
“South Korea has agreed to pay the USA 350 Billion Dollars for a lowering of the [tariffs] charged against them by the United States,” Trump said in a Truth Social post. “Additionally, they have agreed to buy our Oil and Gas in vast quantities, and investments into our Country by wealthy South Korean Companies and Businessmen will exceed 600 Billion Dollars.”
Reuters and The Associated Press contributed to this report.
Kimberly Hayek is a reporter for The Epoch Times. She covers California news and has worked as an editor and on scene at the U.S.-Mexico border during the 2018 migrant caravan crisis.