Renocila richardsonae Williams & Bunkley-Williams, 1992 is recorded for the first time from Sarawak coastal waters. During a survey of marine fishes at depth of 200 metres in South China Sea, off the coast of Sarawak from 3° to 5°N and 110° to 111°E, five specimens of Renocila richardsonae were collected from Japanese goatfish, Upeneus japonicus (Houttuyn, 1782) (Mullidae) with average prevalence of 17% and mean intensity of one isopod per fish from examination of 64 fish. The isopod was observed to cause tissue damage on the site of attachment to the host.