The HRM-Pro™, HRM-Swim™, and HRM‍-‍Tri™ heart rate accessories record and store your heart rate data while you are swimming. To view your heart rate data, you can add heart rate data fields (Customizing the Data Screens).

You must start a timed activity on your paired watch to view stored heart rate data later. During rest intervals when out of the water, the heart rate accessory sends your heart rate data to your watch. Your watch automatically downloads stored heart rate data when you save your timed swim activity. Your heart rate accessory must be out of the water, active, and within range of the watch (3 m) while data downloads. Your heart rate data can be reviewed in the watch history and on your Garmin Connect™ account.

If both wrist-based heart rate and chest heart rate data are available, your watch uses the chest heart rate data.