South Korea is moving ahead with plans to build a nuclear-powered submarine by the mid-2030s, according to President Lee Jae Myung
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| South Korean President Lee Jae Myung arrives for the 78th Armed Forces Day at a military base in Gyeryong-City, South Korea |
SEOUL: The announcement marks a significant development in South Korea’s defense strategy and could reshape the security balance in Northeast Asia.
President Lee said South Korea intends to develop and build its own nuclear-powered submarine, with the goal of having the vessel operational around the middle of the next decade.
Unlike conventional submarines, nuclear-powered submarines can remain underwater for much longer periods without needing to surface frequently for refueling. This gives them greater endurance and allows them to operate over long distances.
For South Korea, the plan is closely connected to concerns about regional security, particularly North Korea’s expanding missile and nuclear capabilities.
Pyongyang has continued developing ballistic missiles and submarine-related weapons technology. North Korea has also presented its own nuclear-powered submarine project as part of its military modernization.
Seoul’s proposed submarine would be nuclear-powered, but that does not necessarily mean it would carry nuclear weapons. South Korea remains a non-nuclear-weapon state under the Nuclear Non-Proliferation Treaty.
The project, however, presents major technical and diplomatic challenges.
Building a nuclear-powered submarine requires highly specialized nuclear reactors, advanced submarine technology, extensive testing, and strict nuclear-safety controls.
There is also the question of nuclear fuel.
South Korea has a sophisticated civilian nuclear industry, but obtaining and managing the highly enriched or specially processed fuel needed for naval reactors involves international agreements and safeguards.
The United States is therefore expected to play an important role in discussions surrounding the project.
Washington and Seoul are longstanding military allies, and U.S. forces are stationed in South Korea as part of the alliance.
Any agreement allowing South Korea to pursue nuclear-powered naval propulsion would therefore have implications beyond the two countries.
It could also attract attention from China, Japan, North Korea, and other countries in the region.
For Seoul, the potential advantage is strategic endurance.
A nuclear-powered submarine could spend substantially more time at sea than a conventional diesel-electric submarine, making it potentially useful for long-range surveillance, intelligence gathering, and tracking hostile submarines and naval forces.
South Korea already operates a modern conventional submarine fleet, including the KSS-III class, which incorporates advanced weapons and underwater capabilities.
Moving toward nuclear propulsion would represent a major technological step beyond that existing fleet.
But the timeline remains ambitious.
Designing the submarine, developing or securing an appropriate reactor, establishing regulatory procedures, training crews, constructing infrastructure, and conducting sea trials could take many years.
President Lee’s mid-2030s target therefore represents a long-term national defense project rather than an immediate military capability.
The announcement also comes at a time when countries across the Indo-Pacific are strengthening their undersea forces.
Australia is pursuing nuclear-powered submarines through the AUKUS partnership with the United States and United Kingdom.
China continues to expand its nuclear-powered submarine fleet.
And North Korea has repeatedly highlighted submarine-based weapons as part of its military ambitions.
South Korea’s decision could consequently become another important element in the region’s growing underwater competition.
At the same time, Seoul will need to balance military requirements with nuclear non-proliferation commitments and international safeguards.
The central question is not simply whether South Korea can build a nuclear-powered submarine.
It is whether the country can establish the technological, financial, regulatory, and diplomatic framework required to operate one safely and sustainably.
If the project proceeds on schedule, South Korea could enter the small group of countries operating nuclear-powered submarines by the mid-2030s.
For now, the announcement signals a major shift in Seoul’s long-term naval ambitions—and another indication that undersea capabilities are becoming increasingly important to security in the Indo-Pacific.
