Garmin strap pro plus compatibility for swimming

It is not.

Garmin confirmed that it is

www.garmin.com/.../770963

zevedeos said:

Garmin confirmed that it is

Then why are you asking?

asking if in real world someone measure hr metrics with this device and pro plus because in another Garmin’s page i found out that it’s not compatible and get confused 

support.garmin.com/.../

It might work because Venu 3 supports Pool swimming and Open Water Swimming now. It was not initially supported, but an update brought many workouts.

Anyway if i can't have strap with venu 3 i am wondering if anyone use the hr wrist measures for swimming and if it's more or less accurate

You can chat with Garmin support regarding this and you will get a clear answer in a few minutes. Regarding accuracy, chest straps will provide you with the best accuracy. I just tried to start a Pool Swim workout on my Venu 3 and it said HR can be inaccurate for swimming. So your best bet would be to tie it tighter and then go for a swim 

I have never done swimming with my watch. Sorry cant comment about it.

have you done this? Did you get better results?

This page is probably not updated. Venu 3 supports Running Dynamics, but it is not mentioned in that list. I guess it is best you contact Garmin Support for clear details.