Two specimens of the syngnathid Syngnathoides biaculeatus were collected from the coastal waters of Geoje Ialand and Tongyeong, Korea, represent first record of the species and the genus from Korea. This species is characterized by the following combination of characters: caudal fin absent; opercle without keel; superior and inferior trunk ridges continuous with their respective tail ridges; lateral trunk ridge deflected dorsal behind anal ring. Tail shorter than head and body hexagonal in its subdorsal part, posterior quadrangular, rapidly tapering, without caudal fin, prehensile. Head essentially in line with longitudinal axis of body or bent very little. New Korean names are proposed, "Jal-pi-sil-go-gi-sok" for the genus Syngnathoides, and "Jal-pi-sil-go-gi" for S. biaculeatus.