Silencers (and all devices meant to muffle the sound of a gun) are classified as a prohibited device in Canada. This does not necessarily mean that they cannot be used, but a license is required for use. Although some of the major laws in Canada surrounding silencers are very clear, make sure to check with your local gun shop or lawyer as to lesser known or local laws.
According to Canadian Criminal Code 86.1-3, any person who uses a silencer carelessly--without ensuring that all safety measures have been taken--has committed a crime punishable by up to two years in prison. An example of careless use would be to use a silencer on a hunting trip, as this could endanger other hunters.
Canadian criminal code 88.1-2 states that any person who has a silencer and intends to use it for a dangerous reason has committed a crime that is punishable by up to 10 years in prison. If a person intends to rob a store using a gun that is silenced, but is arrested before the robbery, they could be charged under this law.
It is illegal in Canada to conceal a silencer without a permit for a concealed weapon; according to Canadian criminal code 90.2, any person who does this can be punished with up to five years in prison.
If you are in possession of a silencer without a permit, the penalty can be severe. According to Canadian criminal codes 91.2 and 92.3, possession can lead to a prison sentence of up to 10 years.
Canadians are no longer able to acquire permits for silencers. However, permits that are "grandfathered," meaning they were acquired before the law changed in 1995, are still considered valid. If you are not sure if your permit is valid, check with your local gun shop or lawyer. Be warned that if the permit turns out to be invalid, you may be expected to surrender your silencer.
Laws surrounding airsoft guns are not clear, and some magistrates and law-enforcement officers still consider them dangerous firearms. If you are caught with a silencer for an airsoft gun, it could carry the same penalty as it would for a dangerous firearm.