Knowing more about the parasite will help you avoid getting Swimmers Itch:

• Don’t feed the ducks, geese or swans. Attracting these birds increases their fecal droppings and you know what that means. The cercariae swim on the surface of the water; after all, that’s where the birds are. They can float a long way on the surface, so you probably want to avoid swimming in areas where swimmer's itch is a known problem and when there is an onshore wind. Definitely avoid floating for prolonged periods of time in an inner tube with your body partially submerged.
• Swim in the afternoon.
• Children are particularly sensitive to Swimmer’s Itch. They usually spend more time in the water, have more sensitive skin, and have a greater tendency to play in shallower water where cercariae most often concentrate.
• Towel off with vigor when you come out of the water. It takes time for cercariae to penetrate the skin and you can crush their tiny bodies. Showering shortly after leaving the water also might help.
• People have also noted that waterproof sunscreens and lotions reduce the infections by discouraging the cercariae from penetrating the skin.
• You may want to consider full body UV swimsuits if you are particular sensitive to the parasite.