The thin sand-eel (Yirrkala tenuis) is an eel in the family Ophichthidae (worm/snake eels). It was described by Albert Günther in 1870, originally under the genus Ophichthys. It is a tropical, marine and freshwater eel which is known from the western Indian Ocean, including the Red Sea, South Africa, Mauritius and Réunion. Males can reach a maximum total length of .