Driving changes nothing
Import requirements attach to the animal and to the country it enters, not to the vehicle it arrives in. A dog driven over the bridge from Detroit to Windsor faces the same conditions as one flying into Toronto. Land crossings feel informal because there is no check-in desk, no cargo terminal and often no visible animal inspector, and that informality is where people are caught out. Officers at a road port do ask for documents, and the remedy when something is missing is refusal of entry — which at a land border means turning the car around and solving the problem on the other side.
Entering the United States by road
The CDC requires a completed Dog Import Form for every dog entering the United States, however it arrives: by car, on foot, by ferry or by air. You submit it online shortly before travel and carry the receipt, which carries a QR code, printed or on a phone. The dog must appear at least six months old, be identified by an ISO microchip and look healthy on inspection. Dogs coming from a country the CDC classifies as high risk for dog rabies face extra conditions, including vaccination records the agency will accept and, in some cases, arrival only at an approved port. Cats need no CDC form but must appear healthy.
Entering Canada by road
Canada asks for a valid rabies vaccination certificate for dogs and cats over three months old, written in English or French. It has to be signed by a licensed veterinarian and identify the animal — breed, colour, weight — along with the vaccine product, the date given and the date it expires. A microchip is not compulsory for entry from the United States, but the certificate must describe the animal closely enough for an officer to match it. Puppies under three months and any movement that counts as commercial fall under stricter rules. Expect an inspection fee and keep the original certificate in the cabin of the vehicle, not in a suitcase in the boot.
The Mexican border both ways
Mexico no longer demands a routine health certificate for dogs and cats arriving from the United States and Canada. SENASICA inspects the animal at the crossing, checks that it looks healthy and free of external parasites, and issues its own document. Carrying a recent vaccination record and a vet certificate anyway costs nothing and answers most questions quickly. Coming back north is the demanding direction, because the CDC Dog Import Form applies to a dog re-entering the United States even when it lives there and left a week earlier. Complete the form before you drive back, and check the validity period on the receipt rather than assuming it lasts indefinitely.
Internal EU and Schengen crossings
There is usually no manned post between France and Spain or Germany and Austria, which makes it tempting to assume nothing applies. The scheme still does. A dog, cat or ferret moving between EU countries needs an ISO microchip, a rabies vaccination given after the chip and at least 21 days before the first crossing, and either an EU Pet Passport or, for non-residents, an animal health certificate. Police and customs run mobile checks on motorways, at ferry terminals and on trains. Ireland, Finland, Malta and Norway also require a vet-administered tapeworm treatment for dogs between 24 and 120 hours before arrival, and that one is checked at the point of entry.