Sensi seeds doesn't ship to Canada, but they'll accept your order and mail it and then update their site to say it was returned. They said they'd refund my money, but nothing yet (since Feb 26). They seem good so I think they'll do it.

seedboutique.com shipped seeds from england to me quickly, in BC. I got some from BC Bud Depot as well, but I wouldn't order with a credit card on their website because they say it's encrypted but it is not!

For Canadian shops I would like to try hempdepot sometime, but I can't say anything about them yet.

Marijuana Seeds (cannabis, pot) shipped worldwide
Peak Seeds