It is waterproof.

I've swam with it on in 2 HIMs and one IM, in addition to other races, for the
same reason you mention.

-Jot

As big a deal as Garmin is making of their new Waterproof strap, I am not sure the old one is. I can not find anything in Garmin's site or by googling the HRM1B product number. The strap itself makes no claims nor has any warnings. Unless someone has a manual, I would say the best you can do is anecdotal evidence. I swim in it at about 5 events per year for the last couple of years. No issues so far.

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Brian
Splash - Hammer - Plod

I almost always swim with it. no issues whatsoever. I'm also a sweaty mess when I run, so it's essential underwater when I run as well with no problems. The only "exposed" parts are around the battery and that is watertight.

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MyGearGarage - Track all your gear!

Just a warning, I changed the battery on mine and broke a little plastic piece that formed part of the seal. First post change sweaty bike ride I did I fried it.

So yeah, it's waterproof, as long as you don't ruin the seal like I did :)

They're not making a big deal about their new waterproof strap, it's the waterproof
unit! The 305 is NOT even close to waterproof. The 310xt is.

The strap has a battery compartment that screws in with an o-ring (as I recall). It's
waterproof.

-Jot

I wrap the battery compartment cover with a couple of wraps of electrical tape to ensure the watertight seal. I don't notice the tape vs. the rest of the plastic. This has worked for five tris with swims and lots of road races where I'll dump water on my shirt/jersey to cool off.

The tape isn't keeping it waterproof, the o rings in the battery compartment are

I left mine on during a HIM and if it can stay wet for that long (that is a long time), it must be waterproof.

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"Well, I guess if a person never quit when the going got tough, they wouldn't have anything to regret for the rest of their life." Lance Armstrong to Peter LeFleur

Agreed that the o-rings are the primary seal, I just use the tape as a belt-and-suspenders measure.

X 2

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