leg Cramps

When do you have cramps - from the moment you start or not until later in your swim? When you push of the wall or in the middle of a lap/open water? How much kicking do you do?

Muscle cramps can be caused by dehydration - are you drinking enough prior to/during swimming?

I have pretty inflexible ankles and I strain to keep my toes pointed - this semss to often lead to cramps on longer swims.

<Sigh> 

Since there is pretty much zero reliable evidence of dehydration being a cause for cramps it is more than likely something else such as taxing a muscle group that is ill prepared for the workload it is getting.

The most common accurate explanation for cramps is overuse or underconditioning of the muscle.