Yes, and everyone else

The girls decided to relax on the edge of the pool. Because of this, Kal decuded he would relax too.

While the girls hung on the edge of the pool with their backs to Kal, he decided to relax as well. They would be here a while anyway, so he would have plenty of time to talk and hang out with the girls. This decision would come back to bite him.

Kal decided to relax by floating on his back. Without realizing his trunks were no longer on his body, he slowly raised himself up to horizontal on top of the water. With his eyes closed, his whole body presented itself for all to see. Most revealing, his small package was resting on top of his body.

Neither Kal nor the girls had noticed yet, but it was only a matter of time before someone saw Kal on his most natural state.