No, you cannot top up data since we only have unlimited plans.

NOTE:

※To manage network resources, unlimited data plans are managed by a Fair Usage Policy (FUP). In wireless internet services, unlimited data means you will not be disconnected based on your usage or the amount of data transferred.

We do our best to provide our customers with large amounts of data that they can comfortably use while in Japan. However, depending on the carrier’s decision, the overuse of mobile communication will affect the usage of other customers and may be deemed as irregular usage. If you consume a large amount of data in one day, the service provider will apply a FUP on your WiFi device and the service will be suspended for the rest of the day. You will be able to use the service again from the following day.