All the cases have been found during testing of arrivals at airports. Two of the new cases were close contacts of the first case, a diplomat from Namibia.
Spokesperson Seiji Kihara declined to give further details on the eight passengers, but Nippon Television reported that they were traveling from the United States and parts of Africa.
Japan has banned new foreign entrants to try to keep out Omicron, believed to be the most contagious variant of the new coronavirus so far.
(Reporting by Sam Nussey, Daniel Leussink and Rocky Swift; Editing by Himani Sarkar, Clarence Fernandez and Kevin Liffey)
