Good news for everyone planning on visiting Japan. You can get 14 days free WiFi access for two of the largest providers in Japan, NTT East, and Travel Japan WiFi.
Select which one suits best for you. Travel Japan WiFi has nationwide coverage and NTT East has coverage in Eastern Japan in this cities:
The best is, you can sign up for both. I would highly recommend you to do this before you start your trip to Japan. All you need is your reservation details on a Japan Airlines (JAL) flight. It looks it works for every ticket and every class on JAL.
The JAL website gives a very detailed instruction how to sign-up for both and how to use the service. There is also a link to find out if your destinations in Japan are covered under one of these two providers.
Residents of Japan are excluded from this service.
[Photo by JAL]