You can use Anytime Talk where your phone or tablet has a stable internet connection. Anytime Talk sends and receives the voice by using the internet either via mobile data (3G/4G) or Wi-Fi.
If you have problems to call or if the voice quality is bad, change network type (3G/4G), or change from Wi-Fi to mobile data, or the other way around to improve the quality.
Note! Anytime Talk 1.0 is currently only available in Japan. Availability in other areas to be updated in the future.