Ultra 100K Sierra de Gata 2027
Which GPS watch for Ultra 100K Sierra de Gata
For Ultra 100K Sierra de Gata, what really matters in a watch is that the battery lasts to the finish. We estimate a mid-pack runner's time and recommend the watch whose battery covers it with margin.
Our recommendation
Garmin
Garmin Instinct 3 AMOLED 45 mm
Rugged mountain watch (MIL-STD-810) with AMOLED display, multi-band GPS and onboard topo maps. 13 h in GPS mode with maps on (up to 30 h in standard GPS) and 8 days in smartwatch mode, at 53 g. The AMOLED version fills the gap left by the Instinct 3 Solar, which has no maps.
Why this watch
Ultra 100K Sierra de Gata is run over more than a day (estimate ~23h 45min). You need extreme battery life: a watch that can record 30 h or more in GPS, or one with a power-saving mode and on-the-go charging.
Other options to consider
Garmin
Garmin Forerunner 965
Premium running watch with a 1.4" AMOLED display, onboard topo maps, multi-band GPS and music. Up to 31 h in GPS mode (19 h multi-band) and 23 days in smartwatch mode, at just 53 g. Garmin's top running watch without the bulk of a Fenix: ideal for marathons and single-day ultras with accurate navigation.
Polar
Polar Pacer Pro
Ultra-light running watch (41 g) focused on power-based training and Polar's running metrics. 35 h of battery in GPS mode and breadcrumb navigation. Simple, thin and comfortable, with one of the best training-analysis platforms for road and light-trail runners.
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