The Polar FT1 is water resistant, but Polar recommends not pressing buttons on the unit while it is under water. Pressing buttons may compromise the unit's water resistance and allow water in. You can wear the heart rate strap while swimming, but you may not receive completely accurate readings due to interference from the chlorine in the pool water. Jumping into the water or muscle movement while swimming may shift the transmitter which can also cause inaccurate readings.
Answered on 8/12/2013 by Ryan from Holabird Sports