I've complained about this before, and so have other users, but all prior threads are locked.
I love my Garmin Swim 2. It's almost flawless in the pool.
But with open water, it consistently underreports the distance swum. I've contacted tech support in the past on this issue to no avail. They can't help me; the only advice they offer is to futz with the GPS settings and suggest that the GPS signal is blocked by the water when my hand goes under.
To be clear, THIS IS NOT AN ISSUE WITH GPS SIGNAL. When I download the actual GPS data and plug it in to a calculator, it shows that I swam about 25-35% more than the watch is reporting. When I report this to the support people, they have no answer other than "Well, we can't see your data..."
This is a math problem. Fixable in software. Garmin doesn't care though. Lots of others have reported this issue. It's reproduceable but on a product as old as the Swim 2 they have no interest in addressing it.
Just wanted to vent and document another instance that it's happening.