Probably not what you are looking for (too far, saltwater), but Tribune Bay on Hornby Island is a fantastic location for swimming. The waters are the warmest ocean waters in Canada - on a good day it is pretty close to what you would find in tropical locations. Plus, there is bioluminescence during the summer - makes for a super cool midnight swim.
http://www.tribunebay.com/images/hom...r-aerial-3.jpg
Just thought I would post it up for general information, should anyone be looking for some warmer ocean beaches in Canada.