On October 30th, a steel-cutting ceremony for the third and final vessel of the KSS-III Batch-II submarine took place at Hanwha Ocean’s Geoje shipyards. The KSS-III Batch-II submarine, designed and constructed with domestic technology, is the latest and most advanced diesel submarine for the ROK Navy.
The KSS-III Batch-II, with a displacement of 3,600 tons (surfaced), is 5.5 meters longer than the previous KSS-III Batch-I submarines and is equipped with 10 VLS cells for launching Hyunmoo-IV-4 SLBMs. Additionally, the Batch-II features enhanced combat and sonar systems for improved detection and targeting capabilities, along with a lithium battery system that enables extended underwater operations, making it a core asset in safeguarding national security.
In addition to enhanced sensors and weapon systems, the KSS-III Batch-II is also expected to operate an Anti-Submarine Warfare Unmanned Underwater Vehicle (ASWUUV), currently being co-developed by Hanwha Systems and the Agency for Defense Development (ADD). The incorporation of a manned-unmanned teaming (MUM-T) system is anticipated to extend the operational range and enhance the combat capability of its carrier by remaining underwater for extended periods to detect enemy submarines in advance, thereby ensuring the survivability of manned combat vessels. Additionally, with variable operational depth control, the UUV will effectively monitor and gather intelligence on underwater threats. The ASWUUV is planned to be operational with the ROK Navy by 2030.
The KSS-III Batch-II has also extended its localization rate to over 80% by incorporating more than 70 types of domestically developed and built equipment. With more accessible maintenance, the ROK Navy is expected to achieve more stable submarine operations, while for the shipbuilding industry, this provides a more manageable construction process for future exports, anticipated to boost defense exports.
The KSS-III Batch-II’s third vessel, which began construction today, is scheduled for completion by 2029 and will undergo sea trials before being delivered to the Navy in 2031. The first vessel is set to be launched in 2025 and the second in 2026, both to undergo testing and evaluation for operational deployment.
“With the full-scale start of the construction process for the Jang Bogo-III Batch-II third vessel, we are committed to ensuring the stable construction of this core asset for our military through strengthened collaboration and seamless communication among the public, private, and military sectors, ensuring timely acquisition of these critical submarines.”
Mr. Sang-woo Lee Director of the Korean Submarine Project Division at DAPA
Authors Note
With the finish line for the Batch-II program now in sight, the need for South Korea to bring a significant change to its submarine program has grown—especially as North Korea appears to be in the early stages of constructing a suspected nuclear submarine, potentially with support from Russia. The fact that no decision has yet been made on KSS-III Batch-III reflects an understanding within South Korea that a strategic shift may be necessary to counter North Korea’s nuclear submarine threat. Considering that the final Batch-II vessel, which began construction today, won’t be operational until 2031, the naval situation in East Asia could be significantly more challenging by then.
KSS-III Batch-II
Displacement: 3,600t (surfaced), 4,000t (submerged)
Length: 89.4m
Beam: 9.7m
Draught: 7.6m
Weapons: 6 x 533mm ATP torpedo tubes Babcock International WHLS (K761 Tiger Shark, C-Star-III), Submarine Launched Mobile Mine (SLMM), 10 x VLS (Hyunmoo-IV-4)
Propulsion System: Diesel-Electric AIP, 3 x Rolls-Royce MTU 12V 4000 U83 Diesel Engine, 4 x Bumhan PH1 Fuel Cell
Battery: lithium-ion battery
Speed: 20 knots (submerged)
Range: 18,500km (surfaced)
Watch Naval News’ recent interview on KSS-III with an official from DAPA:
