In some cases, a Visa document is required in order to enter Mexico that does not apply if you hold one of the following documents regardless of your nationality:
If you do require a visa, we strongly advise you to start your application in your home country at least 90 days before the intended date of travel. Visas cannot be obtained within Mexico, because it is an entry document. The corresponding procedures must be done at a Mexican Consulate or Embassy abroad and it may require the receipt of the registration form and payment. For further advice contact your travel agency or the Mexican Consulate or Embassy in your country.
For more information, please go to Information for VISA applicants