A recent study demonstrated the possibility that migratory birds are responsible for the global spread of avian rotavirus A (RVA). However, little is known about what types of RVAs are retained in migratory birds. In this study, to obtain information on RVA strains in migratory birds, we characterised an RVA strain, Ho374, that was detected in a faecal sample from a gull species (Larus sp.). Genetic analysis revealed that all 11 genes of this strain were classified as new genotypes (G28-P[39]-I21-R14-C14-M13-A24-N14-T16-E21-H16). This clearly indicates that the genetic diversity of avian RVAs is greater than previously recognised. Our findings highlight the need for investigations of RVA strains retained in migratory birds, including gulls.