Mexico Vehicle Permit Information

Important Information in regards to Mexico Vehicle Permits:

You do not need a vehicle import permit if the vehicle has foreign plates AND one of the following apply:
You are only driving within what is called the franja fronteriza, which is the area within 20 KM (approximately 12.5 miles) of the entire border
You are in the región fronteriza, which includes all of Baja California, Baja California Sur and Quintana Roo States. It also includes the 20 km along the border with Guatemala and the municipalities of Caborca, Sonora, Comitán de Domínguez, Chiapas and Salina Cruz, Oaxaca.
You are in the green part of Sonora below (however, based on what a SAT official told me, the exception for Sonora is set to expire in January 2019 and it is unclear if it will be extended (Information here has yet to be verified)
Keep in mind that there are restrictions on who can drive the vehicle. Basically, the vehicle owner, his/her immediate relatives (if the owner is a Mexican citizen, the relatives must also be foreign residents) and anyone else as long as one of the authorized drivers is in the car.
If none of the above applies, you need a vehicle import permit. The process on getting it is decently explained and documented:
Getting a permit
Online: https://www.banjercito.com.mx/registroVehiculos/#
In person – at some Mexican consulates and at the border crossings. Info described here: http://m.sat.gob.mx/aduanas/vehiculos/importacion_temporal/Paginas/embarcaciones_banrjercito_ingles.aspx
Non-Mexican citizens will also need a visa or FMM
Permit validity
For Mexican citizens who are residents in the US – 180 days
For foreigners in Mexico – the length of their visa in Mexico (if they extend their visa they need to inform SAT or else they could lose the deposit)

References

The documents that spell this out are in Spanish and can be found here: The PDF available here: http://omawww.sat.gob.mx/aduanas/Portal/index.html#!/temporal
This is in Spanish and I haven’t been able to find a translation
This document provides all of the detailed info about temporary vehicle import permits. If you read it, the only exception to getting a permit that it mentions is the free zone in Sonora
The REGLAS Generales de Comercio Exterior para 2018 (2018 General Rules for Foreign Commerce): http://omawww.sat.gob.mx/moa/Paginas/reglas_comercio_exterior.html
Section 3.4.7 states that vehicles within 20km of the border and the región fronteriza don’t need a permit
These documents don’t lay out the definitions for the “free zones” and border areas. You can find those here http://omawww.sat.gob.mx/aduanas/pasajeros/Paginas/Franja_region_fronteriza.aspx

Disclaimer: Read your policy conditions as not all Mexico carriers provide the same coverages. Coverages can vary based on Mexico insurance carriers and optional coverages. West Coast Global Insurance Services does not guarantee coverages.