The majority of Americans, Europeans, Australians, and citizens of dozens of other nations do not need any special vaccinations or visas to enter Canada, although medical examinations may be required for visitors wishing to stay longer than six months. Passports are now mandatory for travel between the United States and Canada. As long as their single entry visas have not expired, visitors can use them to enter the United States during their stay in Canada. The Citizenship and Immigration Canada website (http://www.cic.gc.ca/english/visit/visas.asp) features further details on visa requirements.
Health and Safety
Most winter visitors to Canada may be far more worried about hypothermia or frostbite than sunburn, but snowy mountains can have just as high a UV index as sunny beaches. Wearing warm clothing and driving slowly with winter emergency kits are the best ways to stay safe during sudden blizzards.
Canada’s biggest summer health hazards are forest fires in isolated western regions and wildlife encounters. The best ways to avoid the latter are staying away from strange animals, staying on clearly marked trails, and not venturing into rural areas alone. The few violent crimes in large Canadian cities are rarely targeted towards tourists, who should nonetheless exercise the same precautions they would use when visiting any other large cities.