Valid Format of “Certificate of Negative Test Result”
Currently, all those who enter, re-enter or return to Japan (including Japanese nationals) are requested to submit a certificate of negative test result of pre-entry COVID-19 test (format (Word)) conducted within 72 hours (from the sampling time to departure time of the flight) when entering Japan.
From March 19, all travelers including Japanese nationals who do not submit a certificate of negative test result will be denied entry into Japan in accordance with the Quarantine Act. Airline companies will reject boarding those without one. Please consult with Embassies or Consulate Generals or Consular Offices of Japan in case it is truly difficult to obtain the certificate of negative test result.
Please refer to this site (PDF) for the latest information on a Written Pledge and Questionnaire which are requested to submit when entering Japan, and quarantine measures after entering Japan.