If you don't know how to swim, STAY AWAY from swimming pools, ponds, lakes, rivers, and other bodies of water.
If you do know how to swim, then ALWAYS make sure that a responsible adult is present while you are swimming.
Whenever you are on a pier, riding in a boat, riding on a jet ski, or any other similar device, ALWAYS wear a properly-fitted life vest, and ALWAYS make sure that a responsible adult is present while you are in or near the water.