Swimming with Garmin HR Strap

You mean under a wetsuit?  Yes, it's fine (you can wear it without a wetsuit too, it probably just would not stay in place)  

I used it at 2 HIMs, just turned it on prior to the swim, it was ready to go by the time I got to my bike.  I was told that it stops looking for heartrate after a while, and you wouold have to press "start"  (I think) again to get it to look, but both times I've used it it's read my HR just fine right when I get to the bike.

Hey Ken! Was it comfortable having the 305 under your swimcap?  How difficult was it to remove your wetsuit with the quick-release wrist strap already on?  Ive been thinking about that and the plastic mount looks like it is just begging to gouge some neoprene.

Back to the OP. I wear the HR strap during the swim all the time, no problem.  I highly recommend a quick release kit if you dont already have one. The best deal I ve found is here : http://www.futurepowerpc.com/scripts/product.asp?PRDCODE=ELGA-0101088900&REFID=FR

I had trouble getting sattelite reception in time when I turned the unit on arrival to T1, so I will turn it on prior to the swim in the future and may try Ken's idea of taking it on the swim in a ziplock.