SEOUL, South Korea — A significant arms race for nuclear-powered submarines is intensifying between North and South Korea. This escalation follows alterations in the United States’ security strategy in the Asia-Pacific region. On November 2, 2023, North Korean state media showcased a photograph of what it described as an 8,700-ton nuclear-powered strategic guided missile submarine. This marks the first public acknowledgment of the submarine’s size and its reportedly completed hull since North Korea initiated its pursuit of nuclear submarines in 2021.
North Korean leader Kim Jong Un emphasized that the new vessel will enhance the country’s defense capabilities in light of what he termed “the negative security situation.” He criticized South Korea’s plans to develop its own nuclear submarines, labeling them as “an offensive act… that must be countered.”
South Korea’s Rapid Naval Ambitions
In response to North Korea’s advancements, South Korea is moving swiftly to establish its own nuclear submarine program. Following approval from former President Donald Trump in October 2023, a pan-government task force was launched to coordinate efforts in this regard. National security adviser Wi Sung-lac indicated that South Korea aims to negotiate an agreement with the United States for military-use nuclear fuel.
Historically, South Korea has sought to develop nuclear submarines for decades, primarily as a countermeasure against North Korea’s expanding nuclear capabilities, which have increasingly included maritime threats. In addition to constructing nuclear-powered submarines, North Korea has conducted tests of submarine-launched nuclear missiles and claimed to have developed nuclear-capable torpedoes. South Korea’s defense minister, Ahn Gyu-back, stated in October that conventional, diesel-powered submarines cannot match the endurance and speed of nuclear submarines being developed by North Korea.
Regional Implications and Strategic Concerns
The United States anticipates that future South Korean nuclear submarines will serve broader regional objectives, particularly regarding Chinese naval activities. During a visit to Seoul in November 2023, Admiral Daryl Caudle, chief of naval operations for the U.S. Navy, remarked that it is a “natural expectation” for these submarines to be utilized to address what the U.S. identifies as its “pacing threat,” namely China.
South Korean President Lee Jae Myung acknowledged this strategic perspective during his October summit with Trump, highlighting that the limited range of diesel submarines hampers their ability to monitor submarines in both North Korean and Chinese waters. Retired South Korean navy captain Yoon Sukjoon noted that it is “a given” that South Korean nuclear submarines will operate in a broader context beyond the Korean Peninsula, suggesting that such operations could contribute to strategic deterrence against the Chinese Navy in the Indo-Pacific region.
Despite these aspirations, South Korea is cautious about provoking military confrontation with China, its largest trading partner. Following President Lee’s comments, his office clarified that references to submarines were limited to operations near its own waters rather than implying any specific confrontation with Chinese vessels. This careful positioning reflects public sentiment, as a recent survey indicated that a majority of South Koreans prefer neutrality in the event of conflict between the U.S. and China.
As South Korea and Japan express interest in developing nuclear-powered submarines, concerns about China’s expanding influence are growing. Political scientist Kim Heungkyu stated that as the U.S. reorients its defense focus, allies in the region are becoming increasingly skeptical of American security commitments. A poll by the Asan Institute found that less than half of South Koreans believe the U.S. would respond with nuclear weapons if North Korea were to attack.
Moreover, a significant portion of the South Korean populace supports the idea of nuclear armament, even at the risk of facing international sanctions or the withdrawal of U.S. troops. “In a new international order without the U.S. in the Western Pacific, South Korea needs a survival strategy based on nuclear weapons,” Kim asserted, noting that nuclear-powered submarines could serve as “an entry point toward a much bigger goal” of nuclear armament.
While the South Korean government is pursuing access to uranium enrichment and spent fuel reprocessing in discussions with the U.S., it has consistently denied intentions to develop nuclear weapons. However, experts like Kim argue that the Trump administration’s policies may inadvertently steer South Korea and Japan toward nuclear armament, regardless of official intentions.
The evolving dynamics in the region underscore the complexities of security relationships and the urgent need for strategic clarity as both North and South Korea enhance their military capabilities.
