Do you need a passport to fly Mexico?

Although tourist visits are permitted without a passport, all other travel must be done with a passport; however, U.S. citizens and Canadian citizens do not need to present their passports when entering or exiting Mexico by air, land, or sea travel at the US/Mexico border. Additionally, as a convenience, those without their passports entering overland by land or sea (i.e. by car boat or on foot), will generally be allowed to continue their travel if another photo identification (such as a driver's license) is presented. If, however, an official requests your passport, you must allow him or her to view it. Failure to present a passport is a violation of Mexican law and you could be arrested or detained until your passport is presented.

If entry into Mexico is by air, and a tourist card/FMM (Forma Migratoria Múltiple) was not given on the airplane, it must be obtained at the point of entry from an immigration officer. Tourists may stay in Mexico for 180 days unless a lesser stay is indicated on the FMM. Those requesting entry via Mexico's southern or eastern borders must obtain an FMM before departure from the United States or before departure from a foreign country to Mexico. Tourist cards (FMMs) cost up to $35 and are good for multiple entry into and out of Mexico for up to 180 days from the date of issue.

Mexican authorities sometimes require additional documentation from foreign nationals who are staying for more than three months. This documentation can include proof of income or financial solvency, residency in Mexico, a bank letter, or a business letter explaining why you are staying.

Tourists planning to stay more than 180 days must obtain a Temporary Resident Visa from the Mexican National Migration Institute (INM). Temporary residents are also required to obtain an FM3 card (Tarjeta de Residente Temporal). There are specific eligibility requirements for temporary residency, including proof of sufficient financial means.