South Korea launches its newest submarine, the ROKS Jang Yeong-sil, at the Hanwha Ocean shipyard in Geoje, Oct. 22, 2025. (DAPA)
South Korea launched the first of three new 3,600-ton submarines this week, marking another step in its efforts to strengthen its undersea fleet and counter threats from north of the border.
The ROKS Jang Yeongsil — the first of the country’s Jangbogo-III Batch-II attack submarines — was officially launched during a Wednesday ceremony at Hanwha Ocean’s shipyard in Geoje, according to a joint statement from the South Korean navy and Defense Acquisition Program Administration, or DAPA.
The diesel-electric submarine, named after a 15th century Korean engineer, is expected to be delivered to the navy in 2027. Its sister ships remain under construction. The third ship’s steel-cutting ceremony took place in October 2024, according to a separate DAPA release that month.
“I believe the Jang Yeongsil, built with our own technology, will mark a new leap toward a smart and powerful military and fulfill its role as the main force in ensuring maritime security,” navy chief of staff Kang Dong-gil said at the ceremony, according to Wednesday’s release.
Compared with the navy’s three existing Batch-I submarines, the Jang Yeongsil features an upgraded combat and sonar system, lithium batteries for greater underwater endurance and speed, improved stealth, increased survivability and better maneuverability, DAPA said.
The agency described Batch-II as a “world-class diesel submarine” and a “core military asset to counter diverse maritime security threats.”
The boat is part of Seoul’s efforts to respond to North Korea’s growing military capabilities, including a submarine fleet of about 70 vessels, according to the South’s 2022 defense white paper.
The Jangbogo-III program aims to help the country establish naval superiority around the Korean Peninsula and boost its ability to detect and strike North Korean submarines, the white paper said.
