These swim trunks are tight. This is exactly what I was looking for! My son has a very tiny waste and no butt. Every pair of swim trunks fit him initially but as soon as they are wet they are falling off and he is forever sporting a plumber butt. These are perfect. European style speedo like trunks. They fit him dry and wet! We have used them in the pool and on the beach. They have been washed and have not shrunk or faded. The only reason I deducted a star was because my son pick the t-Rex pair and the image was not shrunk to fit his size. He did not seem to mind but I found it cheap appearing. Besides the image they work as I need them to.
For reference my son is 4 years old and weighs 31lbs. We bought the size 2-3 years old.