How many times can I go to Canada for a tourist visa a year?

Twice. According to the website of the Canadian Visa Center, as of June 3, 2023, the Canadian tourist visa application was changed from a single round-trip visa to a multiple round-trip visa. Canadian tourist visas are valid for as long as 10 years. Eligible applicants with multiple-entry visas can stay in Canada for up to 6 months at a time, stay in Canada for 6 months at a time and go twice a year.