Turtles are aquatic reptiles and they breathe air through their lungs like other reptiles, mammals, and birds. However, unlike humans and other animals, turtles do not have a diaphragm to help them breathe. Instead, they rely on the muscles in their shells to expand and contract their lungs to take in and expel air.

When turtles are underwater, they hold their breath for a long time and rely on stored oxygen in their body. Some species of turtles can hold their breath for up to several hours. To breathe while underwater, turtles can extract oxygen from the water through specialized membranes in their mouth and cloaca. These membranes allow turtles to extract oxygen from the water while they are submerged, but this is not a substitute for breathing air through their lungs.