Larval cestodes of Anthobothrium sp. (Cestoda: “Tetraphyllidea”) were collected from the gills of the bigfin reef squid, “shiroika” Sepioteuthis lessoniana Férussac in Lesson, 1832 (Cephalopoda: Loliginidae) collected off Shirahama in Wakayama Prefecture, Japan. These specimens were morphologically described with DNA information (28S rDNA and cox1) and reported as a new host record. In addition, records of Anthobothrium species in Japan were compiled, and a list of parasites and symbionts of S. lessoniana was provided.