Four new species of Blastobasis Zeller, 1855 are described from Thailand: B. tridigitella, B. basipectenella, B. bispinaella, and B. ianella. Photographs of the imagos and illustrations of the male and female genitalia are provided.

Five species of Blastobasis are described: Blastobasis murcyae, B. moffetti, B. christou, B. orladelaneae from New Caledonia and B. lososi from Fiji Islands. These descriptions represent, for the first time, a report of Blastobasinae (Coleophoridae) on these islands. Photographs of the imagos, illustrations of wing venation, male and female genitalia are provided as available.