According to the Mexican Ministry of Foreign Affairs (Secretaria de Relaciones Exteriores), some foreign nationals who intend to stay in Mexico for less than 180 days for tourism purposes or 30 days for business purposes can fill out a tourist card for $22 at the border or when landing at an airport after presenting a valid passport. If arriving by air, this amount is included in the ticket price. This service is available to citizens of the following countries: Andorra, Argentina, Aruba, Australia, Austria, Bahamas, Barbados, Belgium, Belize, Bulgaria, Brazil, Canada, Chile, Colombia, Costa Rica, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Great Britain, Greece, Hong Kong, Hungary, Iceland, Ireland, Israel, Italy, Jamaica, Japan, Latvia, Liechtenstein, Lithuania, Luxembourg, Malaysia, Malta, Marshall Islands, Micronesia, Monaco, Netherlands, New Zealand, Norway, Palau, Panama, Paraguay, Peru, Poland, Portugal, Puerto Rico, Romania, San Marino, Singapore, Slovakia, Slovenia, South Korea, Spain, Sweden, Switzerland, Trinidad and Tobago, United States of America, Uruguay and Venezuela (see official list here). Permanent residents of the United States, Canada, Japan, the United Kingdom and countries of the Schengen area, regardless of their nationality, may also obtain a visa on arrival.
The current Mexican tourist card is officially known as the Forma Migratoria Múltiple (Multiple Immigration Form), or FMM. It has a perforation that divides the card into two parts, with some of the same information asked for on the right side as on the left. On entry, after checking your passport and filling in the MMF, the immigration officer stamps your passport and the MMF, separates the MMF along the perforation and gives you back the right-hand side of the MMF with your passport. Always keep the DMF with your passport. It is your responsibility to ensure that the right-hand side of the MMF is returned to the Mexican government at the time of departure so that the barcode can be scanned to indicate that you have left the country on time. For example, if you fly Aeromexico, you will be asked for your passport and MMF when you check in for your return flight, and then your MMF will be stapled to your boarding pass. You must then hand your boarding pass and MMF to the gate agent when boarding. If you lose your DMF while in Mexico, you can expect significant delays and fines before you can leave the country.
Electronic authorisation (Autorización Electrónica) to enter Mexico is available online for citizens of Russia, Turkey and Ukraine. Other nationalities should contact a Mexican consulate to find out the requirements for citizens of their country and may need to apply for and obtain a visa before travelling. If you need more information, Mexico has diplomatic missions in the following cities around the world. Consulates in the United States are usually only open to non-citizens (by phone or in person) from 8:30am to 12:30pm.
When you cross the border by road, do not expect the authorities to automatically signal you to fill in your papers. You have to locate the border office yourself.
The immigration officer at your port of entry to Mexico may also ask you to provide proof of sufficient economic solvency and a return ticket.
If you do not intend to cross the “border zone” and your stay is not longer than three days, US and Canadian citizens only need proof of citizenship. A passport is usually required for re-entry into the US, but an enhanced driver’s licence (or enhanced photo ID) or US passport card is acceptable for re-entry by land or water.