RoKN’s two prominent modernisation programmes are the Incheon (FFXI) and FFXII classes of guided-missile frigates. The platforms feature hull-mounted and towed-array sonars of Thales for improved submarine-prosecution capability and can embark the Agusta Westland AW159 ASW helicopter that has been equipped with Thales’ FLASH Compact Sonics low-frequency active dipping sonar and acoustic processing suite.

In a conventional ASW scenario the South Korean Navy ships, Lynx/Super Lynx/Wildcats helicopters and P3C Orions have an upper hand in a 1:1 ASW hunter killer action. However, the ROKN has only eight AW159 acquired in 2016 and are in the process of acquiring 12 new helicopters which are expected to be operational by 2020 primarily planned to be deployed with the future surface combatants of ROKN. The ROKN will have a force of 16 upgraded Lockheed Martin P-3 Orion maritime aircraft by 2018. Additionally, the ROKN is seeking 20 more maritime aircraft, which would considerably augment its anti-submarine capability.

Given that the maximum submerged speeds of typical North Korean submarines tend to be in the 4-13kts range coupled with their poor indiscretion rates (ratio of time spent recharging batteries at or near the surface to time spent submerged) and largely obsolete technologies including sonars with low ranges, they can easily be detected by the modern sensors on ROKN aircraft and ships at ranges of 15-20nm using sonars and possibly double that using radars if the submarines are snorkeling. Once detected and acquired by the attacking torpedoes sensors, their chances of avoiding these torpedoes (which have speeds of 32 -45+ knots) are very slim., though a handful of NK submarines could notionally penetrate the South Korean ASW barrier using innovative tactics and hugging rocky coastlines, the technological advantages and platforms possessed by the air, surface and undersea platforms of the ROK Navy is more than adequate to counter the conventional North Korean submarine threat (without ballistic missile).