Based on the available documentation, current SMS capabilities through Retell AI are limited to US numbers only(1). The documentation explicitly states: “Current SMS capabilities are limited to US numbers only”(1).
For SMS to Mexico or other international destinations, you would need to check directly with Twilio about their international SMS capabilities and any additional setup or compliance requirements they have for messaging to Mexico. The Retell AI documentation doesn’t cover international SMS configuration beyond the US limitation(1).
If you’re using your own Twilio number (BYOT - Bring Your Own Twilio), you’d manage international SMS permissions and setup directly through your Twilio account(1)(2).