There are quite a few dog beaches in the northern suburbs, but the closest to Duncraig would probably be Hillarys Beach. This is off Whitford Ave, Hillarys, so it would be very quick for you to get there. It can get really crowded so make sure you keep an eye on your dog. Once you get familiar with the ''landmarks'' (and can keep track of each other amongst all the exciting 'doggie smells' that will be distracting for your dog) it will be easier. I found it useful to keep my dog on the leash until I figured out if there were any problem dogs there each time - ie: big ones or angry ones! They might not really be a problem dog but I could figure out my bearings that way too.