Cramps are often a deficiency in diet, or dehydration. Make sure you are getting plenty of potassium ( bananas are a good source ) and are drinking plenty of water. If you are already drinking quart or more try adding some sports drinks that provide potassium.

Cut down on salt, and stretch ALL muscles thouroughly before swim. Combine swimming with Pilates or Aerobics!

Water water water. Drink as much liquid as you can. You should be drinking 8 oz of gatorade/water per 30 minutes to an hour. toe cramps suck, but you can stop them :DD

drink water and really focus on your breathing