From the "horse's mouth", so to speak
https://www.tc.gc.ca/eng/marinesafety/debs-obs-quick-quick_visitor-1610.htmAn excerpt:
The Regulations apply to non-residents:
•If they operate their pleasure craft in Canadian waters for more than 45 consecutive days or,
•If they operate a pleasure craft that is licensed or registered in Canada (including rented or chartered boats).
•The Regulations do not apply to non-residents who operate their pleasure craft in Canadian waters for less than 45 consecutive days. Please note that a proof of residence will be required on board at all times.
Acceptable Proof of Competency for Non-Residents
For non-residents, proof of competency can take one of three forms:
•A Canadian-issued pleasure craft operator card.
•A completed boat rental safety check-list (for power-driven rental boats).
•An operator card or equivalent that meets the requirements of their state or country.