Tango uses your data network to place voice or video calls over 3G, 4G, and Wi-Fi.
Using a Wi-Fi network to place voice or video calls is absolutely free. When you place voice or video calls over the 3G or 4G network, your charges will be based on the data plan you have set up with your mobile provider. Be sure to check with your mobile provider regarding any fees for using your data allowance.
Tango does not use your mobile provider monthly minutes so there are no extra fees or international charges when calling a friend down the street or a family member in another country.