Five rare moray species: "Anarchias cantonensis" (Schultz), "Gymnothorax dorsalis" Seale, G. "intesi" (Fourmanoir and Rivaton), "G. phasmatodes" (Smith) and "G. sagmacephalus" (Böhlke) belonging to subfamilies Uropterygiinae and Muraeninae are reported for the first time off Taiwan. Diagnoses of these five species of moray eels including their fresh coloration and dentitions are provided. A redescription of "G. sagmacephalus" is provided since its description was based on the unique holotype was incomplete, especially due to its damaged tail tip. We add twelve additional specimens, give the statistics of morphological measurements and vertebral formulae for this species, and expand its geographical distribution from Japan to Taiwan.