There are two main ways to use the goggles in open water. 

The first way is to use the built-in open water mode on the goggles, and the second is to pair the goggles with a compatible Apple Watch or Garmin smartwatch. Depending on which method you are using, different metrics will be recorded during the swim.

Goggles' open water swim mode

Swimming in open water swim mode, the goggles will track and be able to display your time, stroke rate, and if a Polar Verity Sense or OH1/OH1 + sensor is connected, your heart rate.

With an Apple Watch or Garmin smartwatch

If you use your smartwatch for open water swimming, your location, time, distance, pace, and heart rate (heart rate not available on Garmin fenix 5 Plus) will be tracked. The metrics will be tracked as normal by the watch and the goggles will serve as the real-time display so that you can see metrics while swimming. In this case, the goggles will not be tracking any metrics themselves.