Garmin Forerunner 170
It gets 20 h on GPS only and logs open-water swims at 41 g. That GPS figure is 3 h short of the Forerunner 70, and there is no triathlon profile.
7.8/10
This score is my reading of published evidence, since I haven't worn the watch. It suits a first race plan well, but testers found heart rate less tight in intervals, and I'd want a chest strap for hard sessions.
Pavel Ryzhikh, 3 November 2026. Scored from published tests and maker data, not from wearing it.
What the maker states
| GPS battery | 20 h, GPS only |
|---|---|
| Smartwatch battery | 10 days, 4 days with always-on display |
| Weight | 41 g |
| Case size | 42.6 mm |
| Water rating | 5 ATM |
| Display | AMOLED, 1.2 in, 390 x 390 |
| Satellite systems | GPS, GLONASS, Galileo |
| Heart rate sensor | Garmin wrist optical heart rate sensor |
| External sensors | ANT+, Bluetooth |
| Training metrics | Training Readiness, Training Status, HRV Status, VO2 Max, running power, race predictor |
| App | Garmin Connect |