ANT+ heart rate broadcasting

Yes. If ANT+ heart-rate broadcasting is a hard requirement, there are several good options. I checked current manufacturer documentation rather than assuming “ANT+ compatible” means the watch can transmit HR.

Best choices

Garmin Forerunner 165

$249.99

COROS PACE 4

$249.00

COROS APEX 2 Pro

$279.00

Garmin vívoactive 5

$269.99

Garmin explicitly says that its watches capable of HR broadcasting over Bluetooth also broadcast over ANT+ when broadcasting is enabled, and its current compatibility list includes the Forerunner 165/170/265/570/965/970, Instinct 2/3, vívoactive 5/6, fēnix 7/8, etc.support.garmin.com

COROS also supports HR broadcasting, including ANT+, although there is an important caveat: COROS's newer documentation is inconsistent about which connection modes are available on particular models, so I'd favor Garmin if ANT+ is the primary reason you're buying the watch.support.coros.com

What I'd buy

Under ~$250: Garmin Forerunner 165 — currently showing around $235–250 in the search results, and Garmin explicitly confirms ANT+ HR broadcasting.

Around ~$400–450: Garmin Forerunner 265 — a much more capable training watch while retaining ANT+ HR broadcast.

If you want maximum battery/ruggedness: Garmin Instinct 3.

One important question: what are you trying to broadcast the HR to? For example, a Peloton, Zwift, Garmin Edge, ANT+ treadmill, bike computer, or gym equipment. If you tell me the receiving device, I can narrow this down to the cheapest watch that is guaranteed to work with it.

Yes. If the gym equipment accepts ANT+ heart-rate sensors, I’d prioritize these:

Polar H10

$104.99

Polar Verity Sense

$104.99

Garmin HRM 600

$169.99

Garmin HRM 200

$79.99

• Polar H10 — best overall; ANT+ + Bluetooth, very accurate ECG measurement, and explicitly designed to connect to gym equipment.www.polar.com
• Polar Verity Sense — if you don't want a chest strap; optical armband with ANT+.
• Garmin HRM 600/200 — excellent ANT+ options for gym equipment. Garmin specifically documents ANT+ fitness-equipment connectivity.www8.garmin.com
• COROS watches can broadcast wrist HR over ANT+, but compatibility varies by model; many newer COROS watches no longer support ANT+ accessories.www.polar.com+1

My pick: Polar H10. If you specifically want a wrist/watch-style tracker rather than a chest strap, tell me your budget and I’ll narrow it to watches that actually broadcast ANT+ HR.