The Canadian provinces of British Columbia and Ontario have the most online information currently available (2024) regarding their local downwinding and surfskiers. Canada has a lot of marine shoreline and large inland bodies of water (much with unsurpassed beautiful surroundings), but paddling in and paddling information from many locations can be sparse, often due to their remoteness and low population. Most of the paddling in Canada is usually going to involve cold water, but the thriving paddling communities that already exist demonstrate one can overcome that barrier (at least when surface ice has cleared).
See British Columbia
Playing on the Slave River
Do your own diligence on what conditions are safe/paddling friendly if at all for your skill level! Tidal changes here are very strong with vastly varying conditions for paddling the tide races. The strong currents and lack of large population centres means there is limited access to hospitals or Coast Guard on-water resources. About Safety
See Ontario
Check province listings also for dealers and stores