If you want to swim in Trogir, Medena beach is one of the best alternatives since its easy to reach and sea is very clean.
Use to boat for 20 Kn per person. By using the boat you will also find chance to see old town from the sea. It takes 20 min to go Medena beach.
If the beach is crowded, pass the crowd, you’ll see the trees. Walk through the trees, the tiny path will take you to an empty bay.