static void Main(string[] args) { // Find your Account Sid and Auth Token at twilio.com/user/account string AccountSid = "ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"; string AuthToken = "your_auth_token"; var twilio = new TwilioRestClient(AccountSid, AuthToken); var callerIds = twilio.ListOutgoingCallerIds(null, null, null, null); foreach (var callerId in callerIds.OutgoingCallerIds) { Console.WriteLine(callerId.PhoneNumber); } }