Saturn's average density is lower than that of water. In fact, Saturn is the only planet in our solar system with a density less than water. If you could find a body of water large enough, Saturn would theoretically float in it. The planet's low density is a result of its composition, which is primarily hydrogen and helium, similar to Jupiter. These light gases contribute to Saturn's overall low density, despite its massive size. This characteristic is unique among the solar system's planets and highlights the distinct nature of gas giants.