You can make a call using your existing sim card via dialling a pre prgrammed local access number. When you download our App it will come pre-programmed with an access number that is local to you and should be free for you to dial using your bundled minutes. No internet connection is needed for this method of placing an international call. If the local number that we supply you with is not free or low cost for you to dial then you can place your call using your mobile data or via Wi-Fi connection.