South Korea launches new indigenous attack submarine

The Republic of Korea Navy has launched its first Changbogo-III Batch-II class submarine, the Jang Yeong-sil (SS-087), during a formal ceremony held Wednesday at Hanwha Ocean’s shipyard in Geoje.

The vessel is the lead boat in the second batch of South Korea’s indigenously developed diesel-electric submarines and is expected to enhance the country’s underwater deterrence posture.

According to the Navy, the Jang Yeong-sil was designed and built entirely with domestic technology and will serve as a core strategic asset in countering a wide range of maritime security threats. The submarine, weighing 3,600 tons and measuring 89 meters in length, represents the next step in the long-term modernization of South Korea’s undersea warfare capabilities.

“This launch signals a leap forward in our pursuit of a smart, elite naval force,” said Admiral Kang Dong-gil, Chief of Naval Operations, who presided over the event. “I am confident that the Jang Yeong-sil, constructed with our own technology, will fulfill its mission as a key force in defending our maritime sovereignty.”

The submarine is named after Jang Yeong-sil, a pioneering engineer and inventor during the Joseon Dynasty, and is equipped with advanced weapons and electronics designed to conduct independent missions throughout the Korean Peninsula and beyond. While detailed specifications remain limited, Batch-II submarines are known to feature improved sensor suites, extended endurance, and enhanced stealth profiles compared to earlier variants in the Changbogo-III program.

In a statement released after the launch, the Navy confirmed that the Jang Yeong-sil will undergo a series of tests and evaluations before being handed over to the fleet by the end of 2027. Upon completion of trials and crew certification, the vessel will be formally commissioned into operational service.

The event marks a milestone in South Korea’s submarine development roadmap, as the Batch-II platform reflects refinements in both engineering and mission flexibility. The Changbogo-III project, also known as KSS-III, aims to deliver a new generation of conventionally powered submarines capable of launching land-attack cruise missiles and sustaining extended operations across blue-water and littoral zones.

Hanwha Ocean, formerly known as Daewoo Shipbuilding & Marine Engineering (DSME), has been the primary builder of the KSS-III submarines. The company has remained central to South Korea’s ambition to transition from submarine importer to full-cycle manufacturer and exporter.

South Korea’s Navy said it will continue to prioritize the integration of high-end science and technology into its force structure. “We will further strengthen our naval power based on advanced defense technology to firmly safeguard Korea’s maritime sovereignty,” the Navy said in its statement.

The ability to build and operate indigenous platforms like the Changbogo-III Batch-II gives South Korea an edge in both strategic autonomy and future defense export potential. The country is already in talks with several nations interested in its submarine technologies.