South Korea receives another upgraded Jang Bogo submarine

The Republic of Korea Navy (RoKN) has received another upgraded Jang Bogo (KSS-I)-class diesel-electric submarine (SSK), the country's military procurement agency, Defense Acquisition Program Administration (DAPA), announced on 12 August.

The vessel, ROKS Jeong Un , was handed over on the same day of the announcement in a ceremony attended by senior naval officials and representatives from local shipbuilder Hanwha Ocean, the agency added.

Work on Jeong Un began in March 2023, and the vessel has since completed its refurbishment and evaluation processes, with Hanwha Ocean having been appointed as the main contractor in the upgrade programme.

“With the upgrades and improvements, the vessel's ability to carry out operations, such as the detection, identification, and interception of hostile vessels, has been greatly improved when compared to its original configuration,” said DAPA.

“In particular, given how the newer combat systems have been developed domestically, the military's combat operations are now greatly enhanced, given the availability of logistical support in-country,” it added.

Main features

South Korea operates a fleet of nine KSS-I-class submarines, and the vessels were commissioned between June 1993 and December 2001.

Except for the first-of-class submarine, which was built by German shipbuilder Howaldtswerke-Deutsche Werft (HDW) in Kiel, the rest of the KSS-I vessels were either assembled or built by South Korea's Daewoo Shipbuilding and Marine Engineering (DSME) at its Okpo shipyard under a technology transfer agreement. DSME is the predecessor to Hanwha Ocean.