Bavayia crassicollis is endemic to Province des Iles, New Caledonia. The species is confined to Îles Loyauté; confirmed only from Maré and Lifou. It appears to be widespread on Maré and Lifou, but its occurrence on Ouvéa, Tiga and other smaller islands is unknown. It occurs at elevations of up to 150 m. The extent of occurrence is approximately 1,850 km² ^{(estimated from the area of the islands).}