Check out the "airgun" law sheet on the RCMP.GRC website. That will solidify your understanding of what is legal and not. A little black and white, but very clear.
Airsoft guns may or may not replicate real firearms with near prescision which causes a few regulation issues. There are several posts on this, and should be read in detail for thorough information.
The general idea is that you "should not" import guns on your own. Check with licsenced retailers, they can probably get you what you want. As the CBSA has it's own rules they can seize or destroy anything they want within reason.
Another major point is that replica firearms are prohibited devices. That would include any device that "replicates a firearm with near precision". The Canadian firearms program came up with a standard to help with this. Any airgun that replicates a real firearm with near precision that is capable of inducing bodily harm with a projectile is legal. Basically they decided that a standard 0.2 gram BB traveling between 407-499 is capable of hurting someone. And a replica cannot hurt someone. So to move into the "non replica" classification happens at 407 FPS plus. Once the Airsoft gun "can" hurt someone.
It makes sense in a political/beauracratic kind of way. But is is a goofy way of going about it. Airsoft is legal once you can shoot someones eye out, lol.
Do some more reading and talk to a few retailers, but that's the basic idea. Make sure to check out the airgun fact sheet on the RCMP website. There are links to it on these forums. As well as stories and experiences. Airsoft can be a very rewarding hobby, wether you play or collect.
ďREALITY IS LIKE A STONE. TO MANY ITíS HARD AND COLD, THEY CANíT HUG IT OR EAT IT, IT ONLY FRUSTERATES THEM AND DOESNíT DO THEM MUCH GOOD. TO OTHERS ITíS STRONG AND DEPENDABLE, YOU CAN BUILD WITH IT, BUILD UPON IT, OR WORK WITH IT, ALSO USE IT TO SMASH PEOPLE IN THE FACE.Ē