This reminds me of the GPS which is switched off during the standard swimming app. For open water swimming, you have to use a free app of the Connect IQ-Shop - and it works quite well for me.
This is also something where some users will think it's fine, while it's bad for other users. And some that think it's fine really don't have anything to compare it to, so it might not be fine.
Did you read anything about the device before you bought it? The fact that there is no open water swim activity and that there is no HR reading from the wrist sensor for pool swimming are in the spec sheets.
Reliable enough for who? Some people may find it reliable enough and others not. It would be good to have the choice.... but it would certainly reduce Garmin support to not have to deal with it.
Not reliable enough? No, that's not it. Like runners doing speed work at the track, swim workouts tend to be targeted to reach a specifically set distance within a certain time interval, with rest intervals in between. In most cases, heart rates drastically rise and fall at such disprotionate levels between swim and rest intervals, it's hard to get an accurate picture of your overall workout zone intensities. There's nothing wrong with the watch's reliability to accurately track your heart rate. To be perfectly honest, I currently use the Vívoactive HR for swimming, which does track heart rate data during swimming, and I use the Vívoactive 3 for running. I'm currently experimenting with paying for a swimming app in the Garmin Connect IQ Store that'll reprogram the default programming for swimming. So far, none of the FREE swimming apps in the Garmin Connect IQ Store enable it. In all fairness, ALL free swimming apps in the Garmin Connect IQ Store are pretty crappy. If you want a good one, you gotta pay for it.
