Americans returning from Mexico require a passport, birth certificate, resident alien or a SENTRI card. You must prove that you are a legal resident of the United States, not a citizen, to get in to and out of Mexico. However, you are strongly encouraged to keep a passport on you at all times to provide identity information and for banking purposes. You will be issued a blue tourist card valid for usually 90 days when you enter Mexico and this must be surrendered upon leaving Mexico. If you travel by air, you must have a valid passport.
The Western Hemisphere Travel Initiative hosts certain Trusted Traveler Programs. The SENTRI program is part of that initiative that makes traveling across the U.S./Mexico border easier for frequent travelers and is issued by the U.S. Customs and Border Protection agency of the Department of Homeland Security. The SENTRI card pre-approves those accepted travelers giving them access to dedicated commuter lanes at the border crossing. SENTRI cards are valid for five years and require an interview, fingerprinting, and fee to obtain. You can apply online.
If you are returning from Mexico to the United States after entering the country with a vehicle, you first must go to any Mexican Army Bank, called a Banjercito. Turn in your temporary import permit that you obtained when you entered the country as well as the Vehicle Return Promise. Also, you must turn in your tourist card. You will get your vehicle security deposit back if you used that method upon entry or get your bond agreement returned if you used that method of vehicular entry into the country. Border crossing wait times to reach the primary inspection booth are available on the U.S. Customs and Border Protection site of the Department of Homeland Security.
Americans have increasingly become targets for crime once they cross into such cities as Tijuana, Ciudad Juarez, and Matamoros. There are military troops deployed in regions of the country that Americans tend to frequent as tourists, including border regions. Kidnapping of non-Mexicans continues targeting mostly the wealthy and middle-class. “Express kidnappings” are very lucrative and Americans have been known to be accosted in plain sight. The U.S. State Department strongly suggests that Americans consult with their travel medical insurance company regarding if their travel insurance policy is valid in Mexico and whether it will cover emergency expenses.
If you have lost your passport or if it or any other identity papers have been stolen, you need to contact one of the many American consular offices in Mexico for more information and possible emergency services before return to the United States.