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Certain knives are designated as 'prohibited weapons' pursuant to the Criminal Code of Canada. Section 84(1) defines such knives as "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".[10][11] By law, only those who have been granted exemption by the Royal Canadian Mounted Police via the Canadian Firearms Program are allowed to possess (but not acquire) prohibited weapons.

If one is found to be in unauthorized possession of prohibited weapon by any law enforcement officer, he or she is liable to maximum of 5 years in jail and the weapon being seized. The peace officer can then apply to a provincial court judge for the said weapon to be forfeited and be disposed as he or she sees fit. The import and export of such devices are also strictly regulated and enforced by the Canada Border Services Agency.[12]

Examples of such knives include:[13]

automatic knives such as switchblades
centrifugal knives such as flick knives or butterfly knives;
gravity knives;
Constant Companion (belt-buckle knife)
finger rings with blades or other sharp objects projecting from the surface;
push daggers;
spiked wristbands;

One-handed opening knives have been designated as legal to import by Canada Border Services as long as they don't fall into one of the prohibited categories.

There is no length restriction on carrying knives within the Criminal Code of Canada; the only restriction is for concealed carry.