TIPS FOR TRAVELERS TO MEXICO
Department of State
Bureau of Consular Affairs
Publication 10571
August 1998
Other useful precautions are:
Leave a detailed itinerary and the numbers of your passport or other citizenship documents with a friend or relative in the United States.
Bring either a U.S. passport or a certified copy of a birth certificate and photo identification.
Carry your photo identification and the name of a person to contact with you in the event of serious illness or other emergency.
Keep photocopies of your airline or other tickets and your list of travelers checks with you in a separate location from the originals and leave copies with someone at home.
Leave things like unnecessary credit cards and expensive jewelry at home.
Bring travelers checks, not cash.
Use a money belt or concealed pouch for passport, cash and other valuables.
Do not bring firearms or ammunition into Mexico without written permission from the Mexican government.
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I'd print the bottom of this page with the phone numbers of the US Consulates.
Consular Information Sheet - Mexico
Leather was a good buy the last time I was there. That's been quite a few years ago though.