Adults are brown-grey sometimes showing traces of the juvenile markings. The plastron of the juveniles is a beautiful slate-grey. The spiny soft- shell gets its name from the cone like projections on the leading edge of its carapace. The smooth soft-shell gets its name because to a large degree it lacks the spiny protuberances of its relative. Smooth soft-shells have faint markings as juveniles on a tan carapace with light colored markings on the side of the head.
Adults often develop a darker mottled brown color on the carapace.
Plastrons of smooth soft-shells are very light or white in color with visible callosities. This means that there is direct oxygen transfer through highly vascular papillae in the turtles throat and anus. This appears externally in the continual swallowing movements observed in soft shells while submerged. In the wild soft-shell turtles inhabit all types of waters and waterways, from streams and rivers to lakes ponds and sloughs. They spend most of their time in the water or buried in the substrate at the bottom.