Are you inadmissible because of past criminal activity?
In general, temporary residents and applicants applying for permanent residence are considered to be criminally inadmissible if the person:
– was convicted of an offence in Canada;
– was convicted of an offence outside of Canada that is considered a crime in Canada; or
– committed an act outside of Canada that is considered a crime under the laws of the country where it
occurred and would be punishable under Canadian law.
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I was convicted of driving while impaired by alcohol or drugs. Can I enter Canada?
If you’ve been convicted of driving while impaired, you may be inadmissible to Canada for serious criminality. This means that you generally can’t enter Canada. If that’s the case, there are options for you to enter Canada temporarily, or to become admissible again.
See here
New cannabis-related penalties took effect on October 17, 2018. Cannabis-related crimes include:
– illegally producing, distributing or selling cannabis
– illegally importing or exporting cannabis or cannabis-related products across Canada’s international borders
On December 18, 2018, impaired driving penalties took effect. The impact of these penalties on permanent and temporary residents could be significant.
See here