Boreholes in the shells of Cryptopecten vesiculosus and Chlamys (Chlamys) irregularis from the Latest Pleistocene Moeshima Shell Bed of Japan are compared with boreholes made by known hole-boring predators and commensals. The morphology of the boreholes and the ecology of the bored bivalves suggest that the boreholes were not made by naticid or muricid snails, or octopods. The locations of the boreholes in the two fossil scallops are closely comparable to the position of boreholes made by Capulus dilatatus in some Recent scallops.