Summary: T-Mobile is expanding their VoIP service outside the US and is now testing calls to 40+ countries. Using the free T-Mobile Bobsled app for iOS, Android, Windows and Mac you can call your friends in these countries for free.
The free mobile VoIP apps like Nettalk, Bobsled, Google Voice, Magic Jack etc available for iOS and Android lets users make free phone calls to the US and Canada. But what gives if you don’t have any friends or relatives living there. Bobsled, a T-Mobile cross-platform app that earlier allowed free phone calls only to US/ Canada and your Facebook friends has been updated. The goods news is that Bobsled app now supports login without a Facebook account and also free phone calls to landlines and mobile phones in almost 40+ countries. The complete list includes Australia, Austria, Belgium, Brazil, Cambodia, Canada, Chile, China, Colombia, Costa Rica, Czech Republic, Finland, France, Georgia, Hong Kong, India, Indonesia, Ireland, Israel, Kenya, Korea, Malaysia, Mexico, Netherlands, New Zealand, Norway, Paraguay, Portugal, Puerto Rico, Russian Federation, Singapore, Spain, Sweden, Taiwan, Thailand, United Kingdom, United States, Uzbekistan, Venezuela and Vietnam.
Bobsled app (links below) works over WiFi, 3G/ 4G is available for iOS devices (including iPhone, iPod Touch, iPad) and Android phones/ tablets. Also the desktop apps available for Windows and Mac allows users to initiate free calls from within web browsers too. With Bobsled app you can punch in your friends mobile or landline numbers to start calling for free. VoIP-gasm! While nothing much is known about this offer a tweet sent out from the official Twitter handle suggests that T-Mobile is testing free phone calls to these countries listed above. So probably this offer wont last long, but too good while it lasts. I was able to successfully call landlines and mobile phones in India, US and UK many times. I suggest you to try calling your friends in other countries and let me know if it works via comments.