Calls from outside US/Canada to US toll-free Twilio numbers may not route, depending on the originating carrier. If they do route, then the caller would likely need to pay international dialing charges, just like for any other call to a US local phone number. To ensure the reliability of your service we recommend providing an alternate US local Twilio number for international callers.
Outbound international calls from US toll-free Twilio numbers will route normally if international calling permissions are enabled.