Initially, Sideline was designed to use the minutes from your carrier to let you place and receive calls. Now, you can use WiFi to do this which won't use up your minutes and will help you avoid any fees.
If at any time you are abroad, you can use WiFi to place calls to U.S numbers and not be charged for international calling fees or data.
For a small price, you can unlock this feature!
To subscribe, simply go to your Sideline settings and tap VoIP Calling
The screen below will show that your VoIP Calling setting is enabled
Please note, turning this setting off will not cancel your subscription. It will only turn the setting off and use your carrier minutes.
To cancel this subscription, you will need to go to the App Store to avoid further charges.