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Notice: Mexico Voice Call Dialing Changes for Mobile Numbers (Summer 2019)

The Mexican Federal Telecommunications Institute (Instituto Federal de Telecomunicaciones or IFT) has announced an upcoming numbering plan change. This change will alter the way mobile phone numbers based in Mexico are dialed, and may require you to update your infrastructure dialing plan, or modify your Twilio application.

Impact Timeline

Beginning on August 3, 2019, international dialing from phone numbers outside of Mexico to mobile phone numbers based in Mexico will no longer require a 1 prefix inserted between the country code and the area code.

Using the imaginary phone number 55 1234 1234 as an example:

  • Until August 2, 2019, the correct E.164 formatting for dialing this phone number would be +52 1 55 1234 1234.
  • On August 3, 2019 and afterwards, the correct E.164 formatting for this number would be +52 55 1234 1234.

The IFT is implementing a 30-day grace period for this change. After the 30 days, mobile numbers that still include the 1 prefix will no longer connect successfully.

Will my application be affected by this change?

Twilio customers with applications that regularly dial out to mobile phone numbers based in Mexico will want to review their applications. If you have logic that is automatically adding the 1 prefix, you will want take action to update your application after August 3, 2019.

Additional Resources

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