Excerpt taken from
https://en.wikipedia.org/wiki/Knife_legislation#CanadaCanadaThe Canadian Criminal Code criminalizes the possession of knives which open automatically. Section 84(1) defines "a knife that has a blade that opens automatically by gravity or centrifugal force or by hand pressure applied to a button, spring or other device attached to or in the handle of the knife" as a prohibited weapon. Only persons who have been granted exemption by the Royal Canadian Mounted Police through the Canadian Firearms Program are allowed to possess (but not acquire) prohibited weapons.
If a person is found in unauthorized possession of a prohibited knife by any law enforcement officer, the person is liable to a maximum of 5 years in jail and the weapon being seized. The Crown can then apply to a Provincial Court judge for the weapon to be forfeited and destroyed. The import and export of prohibited weapons is also strictly regulated and enforced by the Canada Border Services Agency.
Examples of prohibited knives include:
any knife, including a switchblade, or butterfly knife with a blade that opens automatically by gravity or centrifugal force or by hand pressure applied to a button, spring or other device in or attached to the handle of the knife;
Constant Companion (belt-buckle knife);
finger rings with blades or other sharp objects projecting from the surface;
push daggers.
Manually-opened or 'one-handed' opening knives, including spring-assisted knives, that do not fall within the categories listed as prohibited weapons definition are legal to own, import and use
There is no length restriction on carrying knives within the Criminal Code, but there is a prohibition against carrying a knife if the possessor intends to carry for a purpose dangerous to public peace or for the purpose of committing a criminal offense.