Perhaps you are bored of your normal ab routine. Perhaps you are looking to start a new routine. The swimming pool can be a great way to work out your abs. Read this article for ways to work out your abs in the swimming pool.
Walk. Walk in the shallow end of the pool [about 3 feet deep]. While you walk back-and-forth across the pool, with each step, pull your knee up to your chest while keeping your back straight. Tighten your abs as your pull your knee up to your chest.
Leg Lifts. In slightly deeper water, [about 4 feet or higher, as long as your head is above the water] perform leg lifts. You will lift each leg one at a time towards your chest. This will be like the exercise you did in step 1 with walking, but in this exercise you will lift your legs to your chest at a much faster pace. In fact, lift each leg to your chest as fast as possible. Try to keep your back straight and tighten your abs as you perform this maneuver.
Tread Water. Go to the deep end. Tread water for one minute. Rest and repeat 5 or 10 times. Keep your abs tight as your tread water. Treading water provides a great work out for your entire body, but also works out your abs.
Get a Kickboard. Do the backstroke kick with the kickboard. Hold the kickboard to your chest and turn on your back. While holding the kickboard, try to do the backstroke kick while keeping your thighs, knees and feet as close to the surface as possible.
The wall grab. Find an area of the pool deep enough so your feet do not touch the ground. Grab the side of the wall. Slowly lift your knees to your chest while tightening your abs. Repeat at least 20 times.