Does Skype for iPad work over 3G, 4G or WiFi?
You can make and receive Skype-to-Skype calls, call mobiles and landlines, and send and receive instant messages over 3G, 4G and WiFi.
However, to ensure the best call quality with Skype for iPad, we recommend that you use a strong WiFi connection and make sure you don’t have a lot of other applications running on your device.
Skype-to-Skype calls are free, and you’ll only need a little Skype Credit or a subscription to call mobiles or landlines. Operator data charges may apply when using Skype over a mobile data connection.