Thunder Bay – Gunilda – Great Lakes & Ontario

Site Overview

Thunder Bay – Gunilda in the Great Lakes & Ontario region offers expert-level technical freshwater diving with luxury yacht resting at 100 metres in crystal-clear Lake Superior water. The site features depths from 60 to 100 metres with low biodiversity including Lake Trout, Whitefish, and freshwater organisms in crystal-clear Great Lakes water. The exceptional visibility of 20-30 metres showcases the preserved wreck structures and geological formations that make Ontario one of the world's premier freshwater diving destinations. The cold, nutrient-rich waters support extraordinary biodiversity with colourful invertebrate communities, large predatory fish, and marine mammal encounters that make every dive rewarding. Professional dive operators provide guided experiences with equipment rental, boat transport, and local knowledge that enhances the diving experience significantly. The site attracts divers from across Canada and internationally who seek the unique combination of cold-water marine ecosystems, historical significance, and accessible diving infrastructure. Underwater photographers will find exceptional opportunities with diverse macro subjects, wide-angle reef landscapes, and the dramatic lighting that cold-water environments provide. The diving season extends from late spring through early autumn, with peak conditions during the summer months when water temperatures are highest and marine life is most active. The cold, nutrient-rich waters of the region support extraordinary biodiversity with colourful invertebrate communities, large predatory fish, and frequent marine mammal encounters that make every dive rewarding for experienced cold-water divers.