After some major redesign works, the very first improved Type 039A submarine (No.321) entered solution in April 2001, followed by the 2nd (No.322) in Dec 2001. .Since then more ships have already been entered solution utilizing the PLA Navy. Elimination for the stepped design for conning tower is the main artistic cue for recognition of 039A variant. A brand new layer of anechoic tile was put on further decrease the sound. Weighed against Type 039, the underwater performance and noise degree of type 039A submarine ended up being more satisfactory.
