Communist China acquired former Soviet S-class submarines according to the Australia Station Intelligence Summary dated 1 October 1956

An item reported that the Chinese Communist Navy was possible increased with 6 to 8 former Soviet S-class submarines.(1)

Note

1. Jane’s Fighting Ships 1958-1959 reported the presence of 4 S-classe submarines (S400-403) with a displacement 780 (standard)-840 (surfaced) tons and further more 4 former Soviet W-class, 1-M I and 1-M II classes and 4-ShShuka-class.

Source

Website Royal Australian Navy, Sea Power Centre.