Lake Superior Provincial Park is a 12 mile out and back trail located near Algoma, ON. The trail is primarily used for sea kayaking and is accessible from March until November.
Coastal trail VERY difficult, but very impressive and interesting. Involve crawling under rocks, and some almort rock climbing. NOT FOR KIDS!
Avoid the Agawa river part of the trail as it is infested with deadly mosquitoes like I've never seen in my life! And I have travelled!