Question: I'm Canadian - do I need a passport to travel to Mexico?
November 1, 2007
The U.S. Western Hemisphere Travel Initiative is phasing in passport requirements for travel between the U.S., Canada and Mexico. How does this affect Canadians planning to travel to Mexico?
Answer: It's not an official requirement for Canadian citizens to present a passport for entry into Mexico at the moment, but you do need one if you're traveling via the United States by air. If you have a direct flight from Canada to Mexico, or if you're traveling over land, you must show proof of identity and citizenship - such as a birth certificate and driver's license.
Keep in mind, however, that a passport is the best form of international identification and having one can help prevent hassles! This from Passport Canada's Web Site:
Although the Government of Canada recommends that Canadians travelling to any destination outside of Canada carry a valid passport, it is not mandatory to do so for travel to Mexico.More Mexico Travel Q&A

