In Tubuai, two species and one subspecies were known, all endemic. We found Australdonta radiella radiella in abundance, with fresh shells. Australdonta tubuaiana was found in two localities in the western part of the island, including the type locality, but only old shells were found. Only one fragment of Australdonta pharcata was found, not in the type locality. The type locality, now in Taahuaia village, could not be found. We suggest that Australdonta tubuaiana and A. pharcata should be classified as extinct.