Nests are dug mid-May to late July. Hatching occurs in 60-75 days. In parts of their range, two clutches are laid but this is not known from Ontario. Deposit eggs on or within 100 m of shoreline of lakes and streams. At night adults rest on submerged logs in deep water.
Hatchlings require vegetative cover between nest sites and water's edge.
Preferred sites are off shore, near deep water, sunny, with a good view of surrounding area, and a southern or easterly orientation. Basking is important for gravid females in spring for the successful development of their eggs. In fall, basking aids adults in completing food digestion prior to hibernating. People should stay 70-80 m away to avoid disturbing basking turtles. Aquatic corridors are required for movement.