How Do Distance Alerts for Pool Swimming Work on Garmin Watches?

For pool swimming, distance alerts are intended to notify the user when they are on the last length of the target distance. This "bell lap" type of design enables swimmers to modulate their effort and to plan to stop at the wall, rather than starting a turn. The exact timing of the alert depends on the swimmer's pace, stroke rate, and the size of the pool. Typically the alert will activate when the swimmer is approximately one-third or halfway into the last length. 

Since swimmers are not looking at the watch when they are swimming, the alert includes an audible tone and a vibration. The tone is best heard when both the watch and the ear closest to the watch are underwater. Sometimes putting the watch on the other arm can make it easier to hear.

NOTE: Audible tone not available on all models. See your owner's manual for details.