Formalities
Mexico
Holders of a American, Australian, Canadian, British/EU Member Country*, New Zealand, Israeli passports do not need a visa to visit Mexico. As of January 23, 2007, all passengers -- including US citizens -- traveling to or through the USA by air will need to hold a valid passport. US Citizens are no longer able to use their birth certificate / driver's licence to enter the US by air from Mexico. The maximum period of time that a visitor may stay in Mexico without a formal visa is six months. Therefore your passport, regardless of country of origin, should be valid for a minimum period of six months, however long you intend to stay to avoid any potential problems at the port of entry.
Immigration authorities at the port of entry may allow or deny entry of any person into Mexico. If you have a passport that is valid for less than six months and you intend to stay in Mexico for a short period of time -- perhaps a vacation -- the Immigration Officer might allow you entry.
Notwithstanding this, we recommend that you and your family members hold passports valid for at least six months from the date you plan to enter Mexico.
Stop in the USA on your way to Mexico
If you're travelling via the United States, you might need a visa depending on your country of citizenship.
New formalities starting January 12, 2009
If you're on the Visa Waiver Program, beginning January 12, 2009, you will be required by law to obtain a travel authorization prior to initiating travel to the United States under the VWP. This authorization may be obtained online through the Electronic System for Travel Authorization (ESTA™), a free Internet application administered by the Department of Homeland Security (DHS) through a U.S. government Web site. You may apply for travel authorization via the ESTA™ Web site at https://esta.cbp.dhs.gov. Also check the passport requirements in order to benefit from the visa waiver. If you do not meet these requirements you might need to apply for a visa even if you're simply transiting and you're from a country in the Visa Waiver Program.