South Korea's Nuclear Submarine Agreement with the United States

South Korea has finalized a significant agreement with the United States to develop nuclear-powered attack submarines, marking a pivotal moment in their defense cooperation amid rising tensions on the Korean Peninsula. This agreement, announced on November 14, 2025, follows a meeting between U.S. President Donald Trump and South Korean President Lee Jae Myung, where they also negotiated a trade deal that reduces tariffs on South Korean goods from 25% to 15%. Under the terms of the agreement, South Korea will invest $350 billion in the U.S. economy, including $150 billion in the shipbuilding sector.

US trade deal gives Seoul nuclear sub rights, slashes tariffsReutersUS, South Korea unveil details on Korean investments in shipbuilding and subsUnited Press International (UPI)United States backs South Korea’s nuclear submarine plan as leaders expand shipbuilding and defence tiesBBC NewsU.S. to Help South Korea Build Nuclear Attack Submarines

The push for nuclear submarines is primarily driven by the perceived threat from North Korea, which has been developing its own nuclear submarine capabilities. South Korean Defense Minister Ahn Gyu-back emphasized that these submarines would enhance national security and serve as a deterrent against North Korean aggression. The stealth capabilities of nuclear submarines are expected to keep North Korean leader Kim Jong Un "awake at night," according to Ahn.

BBC NewsU.S. to Help South Korea Build Nuclear Attack SubmarinesCityLabUnited Press International (UPI)

The U.S. views South Korea's acquisition of nuclear submarines as a strategic move to counter China's expanding naval capabilities. Admiral Daryl Caudle, Chief of Naval Operations, stated that South Korea is expected to deploy these submarines globally, transitioning from a regional to a global navy. This shift aligns with the U.S. strategy to strengthen alliances in the Indo-Pacific region.

CityLabStars and StripesBBC NewsU.S. to Help South Korea Build Nuclear Attack SubmarinesChina voices concern over South Korea's nuclear submarine

President Lee described the agreement as a "very meaningful advancement" for South Korea, framing it as a vital strategic asset for peace and stability on the Korean Peninsula. The White House confirmed that the U.S. will assist South Korea in sourcing nuclear fuel for the submarines, which has been a contentious issue in their bilateral nuclear cooperation pact.

United States backs South Korea’s nuclear submarine plan as leaders expand shipbuilding and defence tiesUnited Press International (UPI)BBC NewsUS trade deal gives Seoul nuclear sub rights, slashes tariffsU.S. to Help South Korea Build Nuclear Attack SubmarinesReutersCityLab

Despite the optimism surrounding the agreement, there are concerns regarding its potential to escalate tensions in the region. Critics argue that the introduction of nuclear submarines could provoke North Korea and complicate diplomatic efforts for denuclearization. Chinese officials have expressed apprehension, suggesting that the U.S.-South Korea nuclear cooperation could undermine global nuclear nonproliferation efforts.

BBC News

While South Korea aims to build the submarines domestically, there are discrepancies regarding the construction locations, with Trump previously indicating that some vessels might be built in a South Korean-owned shipyard in Philadelphia. Additionally, experts remain divided on how significantly these submarines will alter the balance of power on the Korean Peninsula.

BBC News

The development of South Korea's nuclear submarines is still in its early stages, with significant legal and policy hurdles to overcome. The timeline for construction remains uncertain, and the U.S. and South Korea will need to navigate their existing nuclear agreements to facilitate this new capability. As both nations work to finalize the details, the broader implications for regional security dynamics will continue to unfold.

CityLab