You can check if you are using international longcodes to send messages to a specific destination in Messaging Insights in the Twilio console. Navigate to Messaging Insights via Monitor -> Insights -> Messages.
To check for traffic, use the filters:
- "From Country + Does not Equal + <Country>"
- "To Country + Equals + <Country>"
To check volume per number, tab to "Delivery and Errors" and scroll down to "Outgoing Messages by Top 20 Twilio Numbers". You can export a list of the numbers by clicking on "Download CSV".
Notice: If you are using Alphanumeric Sender ID to send messages, these will also be included in the results.