Every gram matters on a long hike — and a 100g steel watch on your wrist for 10 hours adds up. The best lightweight hiking watches weigh under 50 grams, providing trail-ready features without the wrist fatigue that heavier watches create during all-day excursions.
At 30 grams, the Pace 3 is the lightest GPS watch available — you genuinely forget you're wearing it during long hikes. Dual-frequency GPS for accurate tracking under tree cover, 38 hours of GPS battery for multi-day trips, and a nylon band that breathes and dries quickly. For weight-conscious hikers and ultralight backpackers, the Pace 3 is the obvious choice.
Best for: Ultralight backpackers who count every gram.
The lightest watch on earth that's actually useful. At 21 grams, you can't feel it. The alarm wakes you at camp. The stopwatch times rest breaks. The backlight works in the tent. At $12, losing it on the trail is a footnote, not a tragedy. Many thru-hikers choose the F-91W specifically because it weighs nothing and costs nothing.
Best for: The absolute lightest option for gram-counting hikers.
The "S" (small) version of the Instinct at 40mm and 40g provides full GPS, ABC sensors, and solar charging in a smaller, lighter package than the standard Instinct. Solar charging means indefinite battery life in sunny conditions. For hikers who want full Garmin functionality at minimal weight, the 2S Solar is the sweet spot.
Best for: Full GPS functionality at 40 grams.
The Lightweight Hiking Truth
If GPS matters: Coros Pace 3 at 30g. If budget matters: Casio F-91W at 21g. If solar matters: Garmin Instinct 2S at 40g. Every watch above 50g is carrying unnecessary weight for hiking purposes.