Mexico → United States

CDC Dog Import Form, filled in online by the person bringing the dog (one form per dog, free). The receipt arrives by e-mail after the e-mail address is confirmed; show it printed or on a phone to the airline before boarding and to U.S. Customs and Border Protection on arrival. From a low-risk country the receipt is valid for 6 months and for several entries from the same departure country; a different departure country or a visit to a high-risk country needs a new form. It can be completed on the day of travel.

Microchip of any brand that a universal scanner can read (if the number does not start with 9, check with the vet that it is readable); implanted before arrival, number entered on the CDC Dog Import Form. A dog without a readable microchip, or whose microchip does not match the documents, is refused and returned.

At least 6 months old on the day of arrival — for every dog, including U.S. dogs coming home. Younger dogs are refused and returned to the country of departure.

The dog must appear healthy. Animals are inspected at the port; a dog that looks ill may be held for a veterinary examination and tests at the owner's expense, or refused.

USDA APHIS screwworm certificate: signed by a full-time salaried veterinary official (official government veterinarian) of the region of origin, stating that the dog was inspected for screwworm within 5 days before shipment to the U.S. and is free of screwworm (or was infested, quarantined and treated until free). No set template; it may be a separate document or part of an export health certificate. A certificate signed by an accredited (private) vet should be countersigned by an official vet; from Mexico, an authorised clinical vet (SENASICA MVRA directory) may sign on the official vet's behalf. Checked with the dog at the port.