Squeezing through border bottlenecks during peak holidays and rush hours can be time-consuming. Avoid crossing 7–9 a.m. and 4:30–6:30 p.m.

Just before returning across the border with your car, park and have a customs (aduana) official remove and cancel the holographic identity sticker that you received on entry. If possible, get a receipt (recibo) or some kind of verification that it’s been canceled (cancelado). Tourists have been fined hundreds of dollars for inadvertently carrying uncanceled car entry stickers on their windshields.

At the same time, return all other Mexican permits, such as tourist cards and hunting and fishing licenses. Also, be prepared for Mexico exit inspection, especially for cultural artifacts and works of art, which may require exit permits. Certain religious and pre- Columbian artifacts, legally the property of the Mexican government, cannot be taken from the country.

If you entered Mexico with your car, you cannot legally leave without it except by permission from local customs authorities, usually the Aduana (Customs House) or the Oficina Federal de Hacienda (Federal Treasury Office).

All returnees are subject to U.S. immigration and customs inspection. These inspections have become generally more time-consuming since September 11, 2001. The worst bottlenecks are at busy border crossings, especially Tijuana and, to a lesser extent, Mexicali, Nogales, Juárez, Nuevo Laredo, and Matamoros, all of which should be avoided during peak hours.

United States law allows a fixed value ($400 at present) of duty-free goods per returnee. This may include no more than one liter of alcoholic spirits, 200 cigarettes, and 100 cigars. A flat 10 percent duty will be applied to the first $1,000 (fair retail value, save your receipts) in excess of your $400 exemption. You may, however, mail packages (up to $100 value each) of gifts duty-free to friends and relatives in the United States. Make sure to clearly write “unsolicited gift” and a list of the value and contents on the outside of the package. Perfumes (over $5), alcoholic beverages, and tobacco may not be included in such packages.

Improve the security of such mailed packages by sending them by Mexpost class, similar to U.S. Express Mail service. Even better (but much more expensive), send them by Federal Express or DHL international couriers, which maintain offices in Oaxaca City, Puerto Escondido, Huatulco, Tuxtepec, Salina Cruz, Juchitan, and other larger Oaxaca towns.