Is it permissible to swim whilst fasting?

Q. I am a habitual swimmer and I take part in swimming tournaments. In Ramadaan, will it be permissible for me to swim? Does swimming break the fast?

A. It is not advisable for a person to swim whilst fasting. However, if a person swims whilst fasting and water is swallowed by mistake or enters through the nose and reaches the brain, then the fast will break and Qadha will have to be made of the fast. (Tahtaawi)