Do turtles always stay in the water?

Turtles breath air so they would have to be able to come up for air. Also, turtles can develop fungus infection and shell rot if they don't come up and dry off and bask in the sun everyday. The over exposion to water would eventually kill the turtles. There are very few turtles that could live their whole lives in water, sea turtles might be the only species that could survive their whole lives in water.