Sepia koilados is a species of cuttlefish native to the southeastern Indian Ocean, specifically the North West Shelf in western Australia (18°31′S 118°09′E / 18.517°S 118.150°E to 19°12.6′S 116°25.8′E / 19.2100°S 116.4300°E). It lives at depths of between 182 and 203 m. Males are slightly larger than females. They grow to a mantle length of 68 mm and 58 mm, respectively. The type specimen was collected in the North West Shelf (18°36′S 118°02′E / 18.600°S 118.033°E to 18°39′S 118°04′E / 18.650°S 118.067°E). It is deposited at the Museum of Victoria in Melbourne.