Rebtel
If you’re working with a spotty or nonexistent internet connection, Rebtel may be the international calling app for you. International calls aren’t always free on this app. But when they are, they come with a few tricks that make Rebtel stand out in a crowded marketplace.
For one, you won’t need a cellular or Wi-Fi connection to make some calls. Instead, Rebtel will use a local number to complete the call to other Rebtel users in about 50 countries. If your call recipient lives elsewhere, you’ll need an internet connection and may need to pay a low, flat rate.
Get Rebtel here.