Skenoh Island in the Finger Lakes offers a unique geological snorkeling experience. The site is notable for the presence of oncolites, or water biscuits, which are rare, round limestone rocks found across the shallow sandy bottom. Snorkellers can explore this freshwater reef environment at depths ranging from 1 to 7 metres, with an average depth of 4 metres. Visibility typically fluctuates between 6 and 12 metres, and the site experiences moderate currents. Access is possible via both shore and boat, though a boat is required to reach the island, which sits 180 metres from the shore. The habitat supports various temperate freshwater fish and invertebrates.

Pisces School of Dive features a shore-accessible reef and artificial reef system in Lake Ontario. Divers can explore depths ranging from 5 to 77 metres, with an average depth of 25 metres. The site is suitable for beginners, though the cold water temperatures between 3 and 13 degrees Celsius necessitate a drysuit or thick thermal protection. Visibility fluctuates significantly from 5 to 61 metres, and a mild current is typically present. The environment supports various temperate freshwater fish and invertebrates. Shore entries require caution due to potential surf and shore break. Facilities include parking, toilets, showers, changing rooms, air fills, equipment rental, and boat charters.

Frontenac Island is one of only two islands located in the Finger Lakes. Situated off Union Springs, the site features a limestone base that contains unique stromatoporoid fossils. The rocky habitat surrounding the island provides a distinct underwater environment for snorkelers to explore. Access to this site is by boat, and it is best suited for intermediate snorkelers due to the nature of the location. As a freshwater site in Cayuga Lake, the topography is defined by its geological features and rocky substrate rather than marine life.