Definitely yes, with the use of Internet connection you can make local and international calls with WhatsApp voice call. But, if you use your mobile data to gain Internet access, data charges may apply. Moreover, WhatsApp may be one of the best VoIP apps for Android. However, there is an update of WhatsApp about a security breach that allows spyware installation from a single missed call. We would not recommend it for the time being until the security hole is fixed.