Stay warm in the water and protect your skin from the sun with these thermal swimwear options from Kiefer. We have thermal swim wear for men, women, and children, including water shirts, full body suits, and kid’s wetsuits. Thermal suits are excellent for water aerobics, swimming lessons, and even open water activities. Have fun in the water and stay warm! If you need help finding the right suit for you, start by reading our advice on choosing swimsuit fabrics.