I bought them to wear in the sea. They are NOT suitable for this, as sand does not penetrate well, especially through holes in the ground. However, they have proven to be great for hiking in Hawaii and wearing them in rivers/rock swimming - great grip, very comfortable even without socks. Dirt *seeps* through holes in the floor, but those holes prevent you from slipping. Small pebbles did not hit the sides or the bottom. They have held up very well. Washes easily and dries quickly. I would wear them everyday!