SEOUL, South Korea — South Korea is moving ahead with plans to acquire nuclear-powered submarines following public support from U.S. President Donald Trump, a move that analysts say could intensify a growing arms race across Northeast Asia.
Trump announced last week that South Korea would build its first nuclear-powered submarine in the United States, specifically at the Philadelphia Shipyards. “South Korea will be building its Nuclear Powered Submarine in the Philadelphia Shipyards,” he wrote on his Truth Social platform, signaling a major shift in Washington’s defense posture in the region.
South Korean Defense Minister Ahn Gyu-back welcomed the announcement, telling lawmakers that the submarine would carry “huge” strategic value. Unlike conventional diesel-electric submarines, nuclear-powered vessels offer greater speed, endurance, and stealth—capabilities seen as essential to counter North Korea’s expanding arsenal.
Pyongyang has not officially responded, but regional experts expect a forceful reaction. North Korea is likely to announce its own military countermeasures, potentially accelerating its submarine program, which is believed to be receiving technical support from Russia.
Andrei Lankov, a professor at Kookmin University in Seoul, said the region is already locked in an arms race. “There is growing fear among allies about the reliability of U.S. security guarantees,” he said. “Trump has repeatedly criticized what he calls ‘parasitic allies,’ and that uncertainty is pushing countries like South Korea to expand their military capabilities.”
Lankov added that North Korea’s rapid military development—including solid-fuel intercontinental ballistic missiles and a growing nuclear warhead stockpile—has heightened Seoul’s urgency. He also cited China’s military expansion and Russia’s alleged support for Pyongyang as destabilizing factors.
Ahead of Trump’s visit to South Korea for the Asia-Pacific Economic Cooperation (APEC) forum on November 1, North Korea tested a hypersonic missile and launched cruise missiles. On Monday, the regime conducted additional missile and artillery tests as U.S. Secretary of Defense Pete Hegseth visited the Demilitarized Zone.
Elsewhere in the region, China is conducting sea trials for its third aircraft carrier, the Fujian, while increasing military pressure around Japan’s Okinawa islands and the South China Sea. Taiwan is ramping up defense spending, purchasing 66 F-16V fighters and glide bombs from the U.S.
Japan is also expanding its defense budget, aiming to double spending to 2% of GDP by April. Prime Minister Sanae Takaichi recently confirmed the plan during a meeting with Trump in Tokyo. Japan has signed deals to supply warships to Australia and is negotiating similar agreements with New Zealand and the Philippines.
Dan Pinkston, a professor at Troy University’s Seoul campus, warned that the region’s decades of relative peace are unraveling. He said South Korea’s pursuit of nuclear-powered submarines could eventually lead to nuclear weapons development, despite its commitment to the Nuclear Non-Proliferation Treaty.
“South Korea plans to buy U.S. enriched uranium, but it has the capability to produce its own,” Pinkston said. “If these submarines are armed with conventional missiles, it’s not a big leap to nuclear warheads if Seoul decides it needs them for security.”
Analysts say Trump’s endorsement has emboldened Seoul’s defense ambitions and may reshape the strategic balance in Northeast Asia. The move could also complicate diplomatic efforts to contain nuclear proliferation and maintain regional stability.
