Previous surveys of marine and estuarine fishes of Yaku-shima Island, Kagoshima Prefecture, southern Japan, have recorded a total of 958 species. Recent examinations of museum collections and newly-collected specimens during the present study resulted in an additional 29 species recorded from Yaku-shima Island for the first time, plus a further 21 species now represented by voucher specimens, having been previously recorded from Yaku-shima only by underwater observations and/or from photographs. Thus, the number of marine and estuarine fish species from Yaku-shima Island now totals 987, the second highest fish species diversity recorded from a single region in Japan. Of the 50 voucher-based species newly recorded in this study, 11 represented a northernmost range extension and one, a southernmost extension. Color photographs of most are provided.