By completing web check-in, you may skip the check-in procedures at the airport. Web check-in procedures vary depending on the time remaining prior to flight departure.
If you have a connecting flight* on the same day, web check-in service is available for both domestic and international flights starting 24 hours prior to the first scheduled departure time.
The service is also available for itineraries including Japanese domestic flights, but it is not applicable for itineraries with only Japan domestic flights issued as domestic tickets. online