The validity of a single entry visa for visitors entering Canada must be no more than 6 months. You may only go to Canada once with this visa. You may go to Canada for 6 months at a time with a multiple entry visa for any number of times throughout its validity. It is valid for up to 10 years or 1 month before the expiration of the passport. You must arrive in Canada on or before the expiration date of your Canada Immigration in 2021.