Canada enjoys strong ties with a number of nations worldwide. Thus, it provides various visa exemptions to its ally countries. However, there are also other ways to enjoy a visa-free travel to Canada. Below are various ways to obtain visa-free travel to the country.
There are a lot of people who no longer need a visa to visit Canada. Citizens of the following countries are exempted from presenting a visa upon entry to Canada: Andorra, Antigua and Barbuda, Australia, Austria, Bahamas, Barbados, Belgium, Botswana, Brunei, Czech Republic, Cyprus, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Lithuania, Iceland, Ireland, national passport holders of Israel, Italy, Japan, Republic of Korea, Republic of Latvia, Liechtenstein, Luxembourg, Malta, Mexico, Monaco, Namibia, Netherlands, New Zealand, Norway, Papua New Guinea, Poland, Portugal, St. Kitts and Nevis, St. Lucia, St. Vincent, San Marino, Singapore, Slovakia, Solomon Islands, Spain, Swaziland, Sweden, Slovenia, Switzerland, United States, and Western Samoa.
At the same time, if you are a lawful permanent resident of the United States, meaning you have at the least, a green card or an alien registration card, then, you can enter Canada without a visa. You must present your green card and passport when entering Canada. If you have any other evidence of permanent residence, then you may enter the country.
Canada also exempts British citizens and British Overseas Citizens who are re-admissible into the United Kingdom. At the same time, citizens of the British dependent territories such as Anguilla, Bermuda, British Virgin Islands, Cayman Islands, Falkland Islands, Gibraltar, Montserrat, Pitcairn, St. Helena or the Turks and Caicos Islands, who have derived their citizenship through descent, birth, registration, or naturalization, are exempt from visa requirements.
Other visitors exempted from the visa requirements are those holding a British National (Overseas) Passport issued by the UK and born, registered, or naturalized in Hong Kong, those with Special Administrative Region passport from Hong Kong SAR, and those with passports or travel documents provided by the Holy See.

I am a south african citizen…i want to be sure if a visa is required to travel to canada.Hope to read from you soon.
cheers