The United States requires that all dogs entering their country look healthy on arrival. Rabies vaccination and microchipping are not required, but they are recommended.When you are coming back into Canada with a puppy (less than three months old), you just need a statement of age from a veterinarian and to be able to show that you are transporting your puppy under humane conditions. If your dog is more than three months old, you will also need proof of vaccination for rabies.