With au, you can quickly call from Japan to overseas without the need for extra procedures.
"Calling overseas" is a service that enables any of our customers to easily make international calls from their current au phone without the need for extra procedures.
Dialing methods
010 → country code → recipient's telephone number
au International Calling Service charges will be billed the following month by au in combination with au telephone charges.
The charges for each country of the world can be seen here.
Notes
If you are subscribed to an eligible Flat-rate Data service, you can make international voice calls to eligible countries and regions up to 50 calls each up to 15 minutes for a flat rate.