Swim distances are as much as 50% overstated
You can’t calibrate but you can edit the distance in Garmin Connect.
You can't, but there are things you should check that you are using.Like use GPS+GLONASS or GPS+GALILEO, not just the GPS and ensure that every second recording is on, not the smart recording.
Which watch do you have?
Hi - I should have said: it’s a forerunner 945
Thanks. Moved thread to the Forerunner 945 forum.