ROK Submarines
Attack Submarines (Diesel-Electric)
Sohn Won-yil Class (variant of German-designed Type 214) LOA 213′ / 64.9 m TDISP 1,850 tons submerged. (9 active, 2 batches, service since 2007) 
Jang Bogo Class (variant of German designed Type 209/1200) LOA 184-200′ / 56.1-61 m TDISP tons 1300 t0ns submerged. (12, 11 active, service since 1993) See also upgraded Indonesian Navy Nagapasa class subs. 
Midget Submarines
Dolgorae or Cosmos classes LOA ca. 91-110′ / 27.7-33.5 m TDISP 80-175 tons submerged. (11 active, smaller Cosmos appear to have been replaced by Dolgorae, service since 1983) 
The Searchers 