They are swimming shorts, they style surfers wear so they call them board shorts. Made out of 100% polyester, very soft and comfortable, my husband has several pair and just didn't wear these after I bought them. The company Billabong is very popular with beachwear. Does that answer your question okay?
I don't know what the rules are at your schools, but my husband just wears board shorts like regular shorts all the time. In Nevada, the kids could wear these if the school doesn't have a dress code.