Gone are the days you could zip down to Mexico with just your driver’s license and birth certificate. Since January 2007, all U.S. citizens returning from Mexico (and elsewhere) by air, land, or sea are required to have a passport. Canadians may travel to Mexico without a passport; they simply need an official photo ID and proof of citizenship, such as an original birth certificate. All other nationalities must have a valid passport.
Citizens of most countries, including the United States, Canada, and members of the E.U., do not need to obtain a visa to enter Mexico. All foreigners, however, are issued a white tourist card when they enter, with the number of days that they are permitted to stay in the county written at the bottom, typically 30–60 days. If you plan to stay for more than a month, politely ask the official to give you the amount of time you need; the maximum stay is 180 days.
Hold on to your tourist card! It must be returned to immigration officials when you leave Mexico. If you lose it, you’ll be fined and may not be permitted to leave the country (much less the immigration office) until you pay.
To extend your stay up to 180 days, head to the nearest immigration office a week before your tourist card expires. Be sure to bring it along with your passport. There, fill out several forms, go to a bank to pay the US$22 processing fee, make photocopies of all the paperwork (including your passport, entry stamp, tourist card, and credit card), and then return to the office to get the extension. For every extra 30 days requested, foreigners must prove that they have US$1,000 available, either in cash or travelers checks, or simply by showing a current credit card. The process can take anywhere from a couple hours to a week, depending on the office.
Plants and fresh foods are not allowed into Mexico, and there are special limits on alcohol, tobacco, and electronic products. Archaeological artifacts, certain antiques, and colonial art cannot be exported from Mexico without special permission.
Above all, do not attempt to bring marijuana or any other narcotic in or out of Mexico. Jail is one place your trusty guidebook won’t come in handy.
Returning home, you will be required to declare all items you bought in Mexico. Citizens of the United States are allowed to re-enter with US$800 worth of purchases duty-free; the figure for other travelers varies by country.
The consulates in Cancún [1] and Mérida [2] handle passport issues (replacing a lost one, adding pages, etc.) and can help their citizens if they are in a serious or emergency situation, including hospitalization, assault, arrest, lawsuits, or death. They usually do not help resolve common disputes—with tour operators or hotels, for example.
In the United States, anyone under 18 traveling internationally without both parents or legal guardians must present a signed, notarized letter from the parent(s) or guardian(s) granting the minor permission to leave the country. This requirement is aimed at preventing international abductions, but it causes frequent and major disruptions for vacationers.
Links:
[1] http://www.moon.com/destinations/cancun-the-yucatan/cancun-cozumel-and-the-riviera-maya/cancun
[2] http://www.moon.com/destinations/cancun-the-yucatan/the-state-yucatan/merida