Well, this bites. New rules from the Centers for Disease Control and Prevention come into effect on Aug. 1, limiting the transport of dogs into the US. The CDC is working to curb the spread of rabies, which means any pups crossing the border will have to be at least six months old, microchipped, and have proof of rabies vaccination (this last part can be a bit complicated depending on travel history). The rules for bringing dogs north remain the same for now, requiring proof of rabies vaccination for pups over eight months old, but Canada is reviewing the new US requirements.
Roughly a million dogs enter the US each year, and Canada is a frequent country of origin for people selling dogs or bringing them across the border on vacation. That includes breeders who ship dogs to customers south of the border, but also Canadians who bring their pet into the country recreationally. The measures aim to protect both dogs and humans from zoonotic disease, which entails more paperwork and logistics, which you can sort through with the CDC’s online DogBot tool.