How We Compared the Watches
This is a desk-research comparison: we compared manufacturer product pages and manuals, rechecked October 22, 2026, not battery tests we ran ourselves. We compared mode-specific GPS runtime and its accuracy tradeoffs, then maps, lighting, case size, weight and price. Extended or maximum-battery modes must not be assumed to retain the most accurate tracking settings. Manufacturer runtimes are best-case figures, so the picks below build in a margin.
Recommendation correction, October 23, 2026. We have applied the same 1.5-times battery margin throughout. Earlier wording overstated which races the watches could cover without charging. This is our planning rule, not a guarantee of real-world battery life; the specifications below were last checked on October 22.
Model check, October 22, 2026. Garmin has replaced two of the watches this guide compared in September. The Enduro 4, announced October 6, 2026, replaces the Enduro 3, and the fēnix 9 Pro, announced August 25, 2026, replaces the fēnix 8. Our September 14 check said Garmin had not replaced any model; the fēnix 9 had in fact been announced three weeks earlier, and this update corrects that. Apple released the Apple Watch Ultra 4 on September 9, 2026, replacing the Ultra 3. The COROS VERTIX 2S and Suunto Vertical 2 are still current, with unchanged battery figures and weights.
For multiday events, pair your watch plan with the headlamp and battery strategy guide.
#1 - Garmin Enduro 4
Garmin announced the Enduro 4 on October 6, 2026 at $899.99. It keeps the 51 mm case, titanium bezel, sapphire lens and physical buttons, lists 66 g with its fabric band (57 g for the case alone), and has routable TopoActive maps and a white and red LED flashlight. Solar figures assume 50,000-lux exposure, while navigation, music, connected sensors, backlight, temperature and battery age can reduce runtime. Applying our 1.5-times margin gives an expected-duration limit of 80 hours for the 120-hour Extended Battery rating and 40 hours for the 60-hour Max Accuracy rating. A 48-hour race therefore calls for a mode rated to at least 72 hours or a rehearsed charging plan. Test your selected mode with navigation and the other features you will use.
Garmin's 2026 watches name their battery modes by outcome rather than satellite setting: Max Accuracy (60 hours), Normal (80 hours), Extended Battery (120 hours) and Max Battery (210 hours). Garmin does not say which satellite systems each mode uses, but the hours match the Enduro 3's multi-band, all-systems and GPS-only ratings exactly. The Enduro 4 also adds Garmin Epic, which combines several days of activities into one view in Garmin Connect.
The Enduro 3 now sits in Garmin's previous-models range at $799.99, listing the same battery hours under the old mode names and 63 g. If you do not need the new features, it is the cheaper route to the same rated runtime.
#2 - COROS VERTIX 2S
COROS lists the VERTIX 2S at $699, with up to 118 hours in standard GPS, 73 hours with all satellite systems, and 43 hours with dual-frequency enabled. It also lists offline maps, a sapphire display, a digital dial plus buttons, and 70 g with the nylon band or 87 g with silicone. Mode, navigation, music, backlight, and other features shorten real runtime. It has no flashlight, which is the main reason it sits below the Enduro 4.
#3 - Suunto Vertical 2
The stainless-steel Vertical 2 is currently listed at $599 and 87 g. Suunto rates its best-accuracy multi-band training mode to 65 hours and Tour mode to 250 hours, but Tour mode uses lower GPS accuracy and turns wrist heart rate off. The watch includes offline maps, dual-band GNSS, an AMOLED display, buttons, and an LED flashlight. The 65-hour best-accuracy rating allows for about 43 hours with our 1.5-times margin, so it falls short of the 72-hour rating we seek for a 48-hour race. For longer events, rehearse charging or test a lower-power mode and decide whether its tracking compromises are acceptable.
#4 - Garmin fēnix 9 Pro – Solar, 51 mm
Garmin announced the fēnix 9 and fēnix 9 Pro on August 25, 2026, and only Pro models offer solar charging. This guide links the $1,199.99, 102 g fēnix 9 Pro – Solar, 51 mm, which Garmin rates to 100 hours in Extended Battery mode or 211 hours with qualifying 50,000-lux solar exposure; Max Accuracy is rated to 54 and 75 hours respectively, and Max Battery to 186 hours. The standard 51 mm fēnix 9 has no solar lens and is rated to 65 hours in Extended Battery and 45 in Max Accuracy. Every 51 mm fēnix 9 lists maps and a flashlight, but price, weight, display and battery differ across configurations, so check the exact part number before buying.
The fēnix 8 – 51 mm Solar it replaces is still on sale at Garmin for $1,099.99, down from $1,199.99, rated to 95 hours GPS-only.
#5 - Apple Watch Ultra 4
Apple announced the Ultra 4 on September 9, 2026 at $799, in the same 49 mm Grade 5 titanium case, with a 3,000-nit peak-brightness display, dual-frequency GPS, and 100 m water resistance. Its battery ratings moved up across the board.
Read the five figures separately, because they are not interchangeable. Apple lists up to 50 hours of normal use and 84 hours in Low Power Mode, and neither is a workout rating—both are tested against a mixed day of time checks, notifications, two one-hour workouts, and sleep tracking. Standard workout tracking is rated to 18 hours. The number that matters for a race is Extended Workout, rated to 25 hours: tested on an outdoor run without an iPhone, with the heart-rate sensor on, with Low Power Mode active for the duration, and with running form metrics unavailable. Max Extended Workout is rated to 45 hours but additionally disables alerts and splits and withholds further metrics.
For a 24-hour race, our 1.5-times rule calls for at least 36 rated workout hours. Extended Workout's 25-hour rating falls short; it allows for an expected duration of at most 16 hours 40 minutes under that rule. Plan charging for a full day, or test the 45-hour Max Extended Workout mode, which allows for up to 30 hours with the same margin. Confirm that its missing alerts, splits and metrics suit your race. None of these ratings guarantees your actual runtime. Cellular, satellite, and emergency features depend on region, account setup, and coverage and should not replace required race safety equipment.
How to Choose
| Race Type | Best Watch Priority | Models to Compare |
|---|---|---|
| 24-hour loop | A marked loop needs no navigation, so the priority is a single accurate GPS mode rated to at least 36 hours, or a rehearsed charging plan | Enduro 4 and VERTIX 2S: both are rated past 100 hours in their long-battery GPS modes and past 40 in their most accurate modes (60 hours Max Accuracy, 43 hours dual-frequency), so the accurate mode meets our margin for the day. Ultra 4 needs a rehearsed charge or its reduced-function 45-hour mode; the 25-hour mode falls short. |
| 100-mile trail | Route following on the watch and a light source matter as much as runtime, because a wrong turn at night costs more than a dead battery at the finish | Enduro 4, fēnix 9 Pro Solar and Vertical 2: all three list on-watch maps plus a built-in LED flashlight. VERTIX 2S carries global offline maps without a flashlight. Check that your selected mode is rated to at least 1.5 times your expected finish time; for a 30-hour finish, that means 45 hours. A watch flashlight does not replace a race headlamp. |
| 200-mile race | A mode rated to at least 1.5 times your expected finish time, or a rehearsed charging plan | For a 100-hour finish, seek at least 150 rated hours. Enduro 4 (120 h Extended Battery) and VERTIX 2S (118 h standard GPS) both fall short of that margin; plan charging or test another mode with acceptable navigation and recording. |
| Daily smartwatch first | Phone integration and safety features | Apple Watch Ultra 4 for iPhone integration, with mode and charging chosen for your expected duration; compare the fēnix 9 Pro family for longer rated runtime |
Sources
- Garmin - Enduro 4 and Enduro 3 side-by-side specifications, the Enduro 4 product page ($899.99), the Enduro 3 previous-models listing ($799.99), and the Enduro 4 announcement. The announcement's body text gives 320 hours with solar to Max Battery mode, while its footnote and Garmin's specification table give it to Extended Battery; we follow the specification table.
- COROS - VERTIX 2S product specifications and current price
- Suunto - Vertical 2 official specifications
- Garmin - fēnix 9 51 mm versions compared, the fēnix 9 Pro – Solar, 51 mm product page and the fēnix 9 announcement; for the previous model, the fēnix 8 – 51 mm Solar product page and battery information
- Apple - Apple Watch Ultra 4 technical specifications and battery footnotes and current US price
- Models, battery-mode claims, weights and manufacturer-listed prices re-verified October 22, 2026 on the Garmin, COROS, Suunto and Apple pages above. Garmin replaced the Enduro 3 with the Enduro 4 (October 6, 2026) and the fēnix 8 with the fēnix 9 (August 25, 2026); our September 14 check had wrongly said no listed model had been replaced. Apple Watch Ultra 4 figures come from Apple's own specification page and its battery footnotes. Prices, software, and specifications can change.
- Multiday Running - gear review methodology