So let's start with the definition of Airsoft in Canada:
The Criminal Code of Canada does not have a designation or definition for Airsoft. Instead the majority of guns fall under 2 definitions:
The first definition is "Replica Firearm." This definition is defined by any devices that looks exactly like a firearm, but does not fire, or does not function in the equivilant manner of its original counterpart (airguns/airsoft). This definition gave rise to the older Clear-body system to separate Airsoft guns from Replica Models. Replica Firearms are illegal to posses, purchase, and import. NO EXCEPTIONS.
The 2nd definition under the Criminal Code that Airsoft falls under is the definition of "Uncontrolled Firearm. " This defintion is defined by any barrelled device that fires below 152m/s (500fps) from any propellant (air/chemical/throwing). The majority of Uncontrolled Firearms though are Airguns and Air pistols used for small game hunting, and Target sports. Thus this category is freely available to possess, purchace, and import.
Since Airsoft falls under 2 definitions, the Canadian Border Services Agency has problems consistently regulating the importation of airsoft.
Now the fun part begins, Canadian Border Services Agency has had to update their policy on the importation of Firearms, weapons, and Devices because of Airsoft. However, most of their troops on the border are not updated to the changes made to the policy.
The following URL is the complete policy on the importation of these devices. I suggest if you are going to the Border to participate in events in Canada, that you print and bring this manual along with the muzzle velocity documentation of your Airsoft gear.
Importing and Exporting Firearms, Weapons and devices
Paragraph 53b (Page 15) defines Airsoft guns and Paintball guns as the following:
If the device fires at a muzzle velocity greater than 366fps (previously it was 410fps) and less than 500fps, then it is classified as an Uncontrolled Firearm because it is capable of causing bodily harm. These weapons are importable.Airsoft guns and certain types of paintball guns or markers may qualify as a replica firearm, if the muzzle velocity of the projectile does not cause serious bodily harm and their external features are clearly designed to resemble a specific and readily identifiable make and model of a firearm. To be considered a firearm, within the meaning of s. 2 of the Criminal Code, an airsoft gun must have a muzzle velocity in excess of 111.6 meters per second (366 feet per second).
Thus to actually allow your weapon into the country, you need documentation from a gunsmith/dealer stating that your gun has been tested and fires in excess of 366fps.