Yes, if you could find a big enough body of water for it to float on. Saturn is very large and is the second largest planet in the Solar System. However, it is made up mostly of gas and is less dense than water. Since it is lighter than water, it can float on water. None of the other planets in our Solar System can do this because they have a higher density than water. Saturn has the lowest density of all the planets, which means that it does not weigh as much for its size as the other planets do.