A free program for Android, by Rakuten Mobile INC..
SMARTalk is an IP VoIP service for smartphones that allows you to make voice calls over the Internet to any phone number overseas for less than 2.5 cents per minute.
There is no need to register or log in to use it, and you can use the service even if you don't have an Internet connection.
How to use SMARTalk?
1. Download and install the application on your smartphone.
2. Log in with your account information to the application.
3. Select the country to which you want to send a call.
4. Choose the type of call you want to send.
5. Enter the phone number.
6. Click "Start", and the call will be sent.
