What is the most water-resistant smartwatch with heart rate monitor available?

Product ⇅ Price ⇅ Heart Rate Accuracy (%) ⇅ Battery Life (hours) ⇅ Water Resistance (meter) ⇅ Screen Size (inches) ⇅ GPS Accuracy (meters) ⇅ Compatibility ⇅
Amazfit Active 2 Square (Premium)
US 		£98.15 ≈ — up to 10 days 5 ATM 1.75 — Zepp OS; Android; iOS

The Amazfit Active 2 Square (Premium) is a GPS smartwatch with a 1.75 in sapphire protected AMOLED display and BioTracker 6.0 heart rate monitoring. It supports offline maps with turn-by-turn directions and includes up to 160 workout modes, with up to 10 days of battery life under typical use. It's aimed at fitness and multi-sport users who want long battery life and navigation without daily charging.

★ Ideal for

For the most water-resistant smartwatch with a heart rate monitor, the Active 2 Square (Premium) is rated 5 ATM and uses BioTracker 6.0 for heart rate monitoring.

Sources:
Amazfit (Official Store) Best Buy Amazfit (Official Store) Best Buy
Search on:
Amazon Walmart eBay AliExpress JD.com Taobao
Garmin Venu 3 (010-02784-01)
US 		£264.27 ≈ — 14 days in smartwatch mode 5 ATM swim 1.4 in — Bluetooth compatible phone

Garmin Venu 3 is a health and fitness smartwatch with a 1.4 in AMOLED touchscreen display, built-in sports and wellness features, and a battery rated up to 14 days in smartwatch mode. It supports swim-rated water resistance (5 ATM) and includes navigation with All Systems GNSS.

★ Ideal for

For maximum water resistance with a heart rate monitor, the Venu 3 is rated swim 5 ATM and includes wrist-based heart rate monitoring plus All Systems GNSS for outdoor tracking.

Sources:
Best Buy The Home Depot Best Buy The Home Depot
Search on:
Amazon Walmart eBay AliExpress JD.com Taobao
Huawei Watch Fit 3
US 		£52.09 ≈ — 10-day maximum battery life 5 ATM 1.82 in — Android 8.0 or later and iOS 13.0 or later

The Huawei Watch Fit 3 is a slim fitness-focused smartwatch with an AMOLED 1.82 in display, built-in GPS, and heart-rate monitoring. It's rated 5 ATM for water resistance and is designed for long battery life, with up to a 10-day maximum battery life in Huawei's test conditions. It works with both Android and iOS.

★ Ideal for

For the most water-resistant smartwatch with a heart rate monitor available, the Watch Fit 3 is rated 5 ATM and includes an optical heart rate sensor.

Sources:
Argos TechRadar deal page (Amazon listing) Currys (Ireland) Argos TechRadar deal page (Amazon listing) Currys (Ireland)
Search on:
Amazon Walmart eBay AliExpress JD.com Taobao