Hola y bienvenido a Airsoft Canada.
As many have already pointed out, the laws regarding airsoft in Canada are a bit complicated: while airsoft is legal to own, it's generally illegal for individuals to import (there are specific rules etc which make it very difficult and often also very costly). Therefor it's very strongly recommended to buy guns from Canadian retailers.
Accessories, parts (except receivers and certain other restricted items), magazines (as long as they do not have fake bullets, like certain SIG55x or G36 mags), optics, etc, as well as gear (vests, BDUs, etc) are all legal to bring in, so you can bring those items without worry.
If you have a specific custom setup you'd like to "keep", I'd suggest you bring only the parts necessary to customize a Canadian gun. Otherwise sell guns before leaving.
There's quite a large player base here in Montreal (as well as elsewhere in Quebec) with frequent games throughout the year (as Jagdalex pointed out, there are games every two weeks at an indoor paintball field). We occasionally also organize evenings out for food and drinks, so it's a good opportunity to meet and talk to the local players.
Originally Posted by KND
It's not a smart idea to sell stuff there and buy new thing here, due to import tax and whatever shit it is, Most of the related airsoft stuff is turn to more expensive than other place even it's not restricted, I'm not even talking about shipping yet.
I have to disagree since it's often more difficult finding only a receiver than finding complete guns. Specially with the Safesoft guns distributing ICS, they can import a complete gun but cannot import only the receiver.
Bringing only the good upgrade parts and accessories its much easier to just get a new complete gun and re-modify it.