Before coming to Japan, the travelers need to download the mobile application ‘WAmazing’ (for free) and register his/her information. This card is already prepaid, so all the travelers do is just get this card at Narita International Airport (Tokyo) and replace their SIM Card with new one.
※This free SIM card offering will come into effect at February 1st, 2017.

This prepaid SIM card comes with an initial 500 MB data volume allocation valid for 5 days. If more volume and/or the term is needed, one can charge to your card through mobile application.

As I said before, this ‘WAmazing’ application is not just for SIM Card. With this app, you can arrange allocation of taxis in Tokyo area, and book various activities and tours. First target users are travelers from Taiwan and Hong Kong.

This is just the begging. And WAmazing INC. is also planning the extension of their service.

TIPS

1. You must register this app until 4 hours prior to the time you would like to get this card.
2. You can get SIM Card at the machines with Digital Signage. These are installed on the arrival floor at Terminal1/2/3 in Narita International Airport.
3. You may get some online coupon, so check the information that is provided through app.

More detail: check this WAmazing’s Chinese site or Japanese site.
※It seems that other languages are prepared.