Hi, J., I like the other advice you have received so far and have another couple of suggestions. You need to make a total sunblock application at least 15 minutes before the kids go outside. If you are serious about sun protection, I recommend a titanium/zinc oxide physical sunblock. There are several on the market, and while not easy to find at Long's, you can buy them from the website Sun Precautions (www.sunprecautions.com). I use the Solbar SPF 38 when I am in Hawaii, and it is the only thing that has helped me. I am very sun-sensitive and break out with a lot of chemical sunscreens. Another sunblock that is more widely available is Neutrogena Sensitive Skin sunblock SPF 30, which is also a physical block and won't dissipate quickly like chemical sunscreens. The new Neutrogena sunblocks with Helioplex were recommended to me by my dermatologist, but I don't know about their efficacy in the water. Have you thought about having your kids wear sun-protective garments? I can't say enough good things about the shirts, hats, pants, etc. from Sun Precautions. Both of my daughters have worn their sunshirts and I never go to the beach without one, either. The material has a built-in SPF 30. Good luck to you, and it's great that you are aware of this problem. It's a huge concern for all of us who live here in the sunny side of the country. I hope your kids wear hats - nothing is more upsetting to me than seeing little babies and kids out in strollers without hats on! As they say in Australia, "slip slap slop!" (Slip on a shirt, Slap on a hat, Slop on the sunblock!")