RockSTAR Aquapac Armband
The RockSTAR is IP67 rated, so waterproof to 1m for 30 minutes. However, if you are going to be spending extended time in the water then you may want to consider the special Aquapac armband pouch.
The Aquapac armband pouch is specially designed for the RockSTAR unit, and allows you to wear the RockSTAR on your upper arm.
It provides extra protection against water ingress, and peace of mind for you, as well as a neat way to carry the RockSTAR on your person