Box turtles can swim. They are not the best swimmers of the various turtle species, but they do enjoy the water.
Box turtles really enjoy wading and soaking in water, and owners should provide them with an area to soak in the water daily. They require warm water, and cold water can actually disable them. Awkward box turtles also require an easy way to enter and exit the water so they do not tire themselves out and drown while trying to get out of the water. In a natural habitat, most box turtles stay in shallow water because they are clumsy swimmers.