The Rottnest Channel Swim is an annual 19.7km open water swim from Cottesloe Beach to Rottnest Island.
The Rotto Swim app is for swimmers and support crew to track their position along their desired route and receive race updates during the event.
A swimmer or support crew member who sets up their phone to transmit will also allow friends and family to track their progress.
Rotto Swim makes use your devices GPS in foreground and background in order to track your location.
You can disable the apps use of the GPS by changing the Location Services setting to "Never" via Settings -> Rotto Swim -> Location.
Please Note: "Continued use of GPS running in the background can dramatically decrease battery life."