Perform the breaststroke in a deeper area of the pool. The circle motion created as your arms push you through the water, will condition your chest muscles while also strenghening your shoulders. Swim in laps, slowly increasing as you become stronger.
Hold your arms at your sides in the shallow area of the pool, about chest height . In sets of 10, raise your arms forward, until they are even with your shoulders, and then back to starting position. The resistance of the water will tone the muscles of the arms and chest.
Grip the side of the pool and gently raise yourself as if to lift yourself out of the pool. Starting with sets of 10, increasing as you get stronger will give a great arm and chest workout.
Hold both arms shoulder height on both sides of your body, forming an L shape on each. The L would be formed with your arms stretched straight out and elbows bent upwards. Slowly bring each arm inwards towards your body with your elbows still bent. Slowly bring your arms back to starting position and repeat in sets of ten for a great chest workout.