Unlike Europe and North America, Free WiFi hotspots are harder to find in Japan. Some of the services that they say available are only for subscribers. However Japan is working havers hard to provide more Free WiFi spots for travelers.
Some of the places you you may find Free WiFi are
- Airports
- Train Stations
- Covenant Stores
- Coffee Shops
Here is a Free WiFi information provided by Japan Tourism Office.
http://japanfreewifi.jnto.go.jp/eng/wifi-spot-list.php?location=curp