Running Watch Battery: Pick by Hoursprice per 1 hour of 12 models and picks by budget

The pick when comparing running watches by battery is the COROS PACE 4. Up to 41 hours on GPS at JPY 36,300, and JPY 885 per 1 hour of battery, the lowest of the 12 models. For a 6-hour full marathon, every one of the 12 models in the table has enough battery. The difference comes in the mountains. For the 100 miles with a 45h30m time limit, the only 2 models with an official number to record the whole way without charging were the COROS APEX 4 (46mm, 65 hours) and the Garmin Enduro 4 (about 80 hours).

A watch of JPY 30,000 range (3 × 10,000) lasts longer than a JPY 120,000 (12 × 10,000) one

The higher the price of a running watch, the longer the battery. Line up each company's official spec tables with that in mind, and it collapses at once.

Garmin's Forerunner 970 is JPY 121,800 and about 26 hours with GPS. COROS's PACE 4 is JPY 36,300 and up to 41 hours. The price is 3.4 times (121,800 ÷ 36,300), yet the battery is 15 hours shorter, the other way (41 − 26).

What the expensive watches sell is maps, bright screens, music and calls. Battery time is on a different axis. So in this article I decide the battery I need first from "the time limit of the race I enter," and look at price after that.

How to choose a running watch: the conditions I used

I lined up 12 models compared on 3 things from the Japan official pages: weight, battery time with GPS on, and price. It is not in order of sales. The conditions are these 3.

Among the models that satisfy ①, I place those with a small ② higher. I did not compare by how accurate the heart rate numbers are. The official spec tables have no numbers that let me compare models on that.

Comparison table of battery and price for 12 running watches

Scroll the table sideways →

Price per 1 hour ranges from JPY 885 for the cheapest, the PACE 4, to JPY 7,933 for the Apple Watch Ultra 4. That is about 9 times (7,933 ÷ 885).

The catalog battery hours are for the lightest setting

This is the pitfall when reading a spec table. A watch can switch how it receives the satellites that measure position in several steps. The more signals it receives, the faster the battery drains.

Garmin's official page writes the hours for each of these steps. On the Forerunner 970, GPS mode is about 26 hours, and multiband mode, which receives 2 frequencies, is about 21 hours. That is 5 hours shorter, about 19% (5 ÷ 26).

The Instinct 3 Dual Power has an even larger gap, about 40 hours becoming about 24 hours. That is 16 hours, a cut of 4 tenths (16 ÷ 40). Playing music shrinks it further, and the Forerunner 970 is about 14 hours.

So the table's "GPS battery" is an upper limit. If you plan to use a higher setting, read the per-mode lines on the official page. The conditions of the numbers in the table are as follows.

• Garmin: the "GPS mode" line. For the Enduro 4, the standard setting of the activity mode (the battery-extending setting is about 120 hours). The solar addition is not included.
• COROS: for the PACE 4, with all-system GPS used continuously. For the APEX 4, the number at the satellite setting the official site calls "long duration."
• Polar: training mode with high-accuracy GPS and heart rate measurement enabled.
• Amazfit: the Balance 2 is "accuracy GPS mode," and the Active 3 Premium is the single-frequency GPS mode.
• SUUNTO: the highest-accuracy GPS mode. Apple: the official "outdoor workout."

SUUNTO and Apple give numbers for a heavy setting from the start. Even the same "24 hours" or "18 hours" is on a different footing from Garmin's GPS-mode number. Being low in the table does not mean losing under the same conditions.

Work backward from the time limit to the battery you need

What I ask of a watch is that the record does not cut from start to finish. So that it is enough even for the slowest finish, I take the race's time limit as is for "battery hours needed." The race numbers are the same as the official entry guides I read in the article on trail running mandatory gear.

For a full marathon, any of them lasts. Even the model with the shortest time, 18 hours, covers a 6-hour race 3 times (18 ÷ 6). If it is only the full, you need not worry about battery. The half is the same (article on half marathon time limits).

At the line of 21 to 24 hours, 3 models drop out: the Forerunner 170 (about 20 hours), the Forerunner 570 (about 18 hours) and the Apple Watch Ultra 4 (18 hours). If you enter a 70km-class trail, this is the dividing point.

At 33 hours, the PACE 4, APEX 4, Balance 2, Instinct 3 Dual Power and Enduro 4 remain. Only the 46mm APEX 4 and the Enduro 4 reach 45h30m.

Up to JPY 30,000 (3 × 10,000): Polar Pacer

Why this one: Of the 2 models up to JPY 30,000 (3 × 10,000), it has the longer battery and is lighter. 32 hours with high-accuracy GPS and heart rate enabled. For a 6-hour full marathon, that is 5 runs (32 ÷ 6 = 5.3). The official site gives the weight as 40g with the band and 23g without it.

It reaches the 24-hour Hasetsune too, with 8 hours to spare. In the lowest budget bracket, it can see up to a 70km-class mountain. A wide range of coverage for an entry model.

What to watch: It is an older-generation model in Polar's current lineup. It has no function to show maps on the watch. If you want a showy screen, or to handle payments on the watch, a model in a higher budget suits better.

Another candidate is Amazfit's Active 3 Premium. Up to 24 hours with GPS and about 54.6g with the band. It is 8 hours shorter than the Pacer and about 15g heavier. It is a model listed on the Japan official HYROX page, so if you want to track gym stations on 1 watch too, this is it (article on Amazfit's HYROX mode).

JPY 30,000 to 60,000 (3 to 6 × 10,000): COROS PACE 4

Why this one: It has the lowest price per 1 hour of battery of the 12. Up to 41 hours with all-system GPS used continuously. 40g with the silicone band, 32g with the nylon band.

With 41 hours, it covers even Shinetsu Five Mountains' 100 miles (33 hours). From the full marathon to just short of 100 miles, 1 watch carries you through. In this price range, no other model reaches this far.

What to watch: For the 45h30m of FUJI100mi, it is 4h30m short (45.5 − 41). The table price is for the white silicone band model; the aluminum-rim model and the athlete-named model cost more. The differences in the official list were color and material.

The Amazfit Balance 2 in the same price range is up to 33 hours on GPS and about 60g with the band. It is 8 hours shorter than the PACE 4 and about 20g heavier. The reason to choose it is that it has 2 HYROX modes built in.

Garmin's Forerunner 170 is an entry model released in May 2026. 41g, with a GPS mode of about 20 hours. Plenty for a full marathon, not enough for a 70km-class mountain. It is the 1 watch for people who want to keep records in the Garmin app, bought for road races.

JPY 60,000 and up (6 × 10,000): COROS APEX 4 (46mm)

Why this one: Of the 2 models beyond 45h30m, it costs less than half. The gap from the Enduro 4 is JPY 74,200 (138,000 − 63,800). The 46mm model lasts up to 65 hours and is 51g with the nylon band. It is 15g lighter than the Enduro 4.

Even after subtracting the FUJI100mi time limit, 19h30m remains (65 − 45.5).

What to watch: Battery changes a lot with size. The 42mm model is up to 41 hours, the same as the PACE 4. If you buy it for 100 miles, it is the 46mm. The 65 hours is a number at the satellite setting called "long duration," so check the official spec table before buying for the hours at a higher setting. The official price is shown with "from," and goes up with color and model.

If you run 100 miles with a Garmin

On Garmin, the one beyond 45h30m is the Enduro 4. About 80 hours at the standard setting, about 120 hours at the battery-extending setting. In the announcement dated Oct 9, reservations open Oct 15 and it goes on sale Oct 22. From the previous model, built-in storage rose from 32GB to 64GB.

The previous model, the Enduro 3, is 63g, with a GPS mode of about 120 hours on the official page. The official price is JPY 148,000, which is JPY 10,000 higher than the Enduro 4 (JPY 138,000) going on sale Oct 22.

If you choose at about half the price of the Enduro 4, the Instinct 3 Dual Power 45mm. About 40 hours, covering up to the 33-hour Shinetsu Five Mountains 100mile. Solar adds up to 90 hours (maker's figure), but the condition is receiving 50,000 lux of light continuously. In a race that crosses 2 nights, it is not a number to count on.

Telling the siblings apart

Here are the differences you notice only after buying, among similarly named models.

• Forerunner 165 and 170: The 165 shows "discontinued" on the Japan official site. It was about 19 hours and 39g. Its successor, the 170, is about 20 hours and 41g. Buying a 165 left in stores still covers a full marathon, but if buying new, the 170.
• Forerunner 265 and 570: The 265 is the model before the 570, from JPY 60,800, 47g, GPS mode about 20 hours. It is 2 hours longer than the new 570 (about 18 hours). On battery alone, the newer generation is shorter.
• Forerunner 570 and 970: The price gap is JPY 47,000 (121,800 − 74,800), and the battery gap is 8 hours (26 − 18). Only the 970 reaches a 24-hour race. For people who race only on the road, the 570 is enough.
• Instinct 3 Dual Power and AMOLED: At the same 45mm, the AMOLED model with the bright screen is about 32 hours, and the Dual Power with solar is about 40 hours. For long use in the mountains, choose the Dual Power.
• COROS PACE 4 and PACE 4 Pro: The Pro is JPY 69,960 and 60 hours on regular GPS. The gap from the PACE 4 is JPY 33,660 and 19 hours. If you pay that much, I choose the 46mm APEX 4, which is 65 hours and JPY 6,160 cheaper.
• SUUNTO Run and Run 2: The Run 2 went on sale Sep 29, 2026; body 35g, up to 24 hours with the highest-accuracy GPS, and you can load maps on the watch. The previous Run is 36g, up to 20 hours, and JPY 34,650 on the Japan official site. The gap is JPY 25,300 (59,950 − 34,650). The numbers 1 by 1 are written in the SUUNTO Run 2 review.

Models I left out of the table

Models that lacked one of the 3 numbers were removed from the table. I write about them briefly here.

• COROS VERTIX 2S: JPY 93,500, up to 118 hours with GPS. At JPY 792 per 1 hour (93,500 ÷ 118), it works out cheaper than the PACE 4.
• Garmin fēnix 8 (AMOLED 47mm): 73g with the silicone band, GPS mode about 47 hours.
• Polar Grit X2 Pro: JPY 121,000, 79g with the band, training mode 43 hours.
• Amazfit Cheetah 2 Pro: JPY 74,800, about 61.5g with the band, up to 31 hours in the high-accuracy mode that receives 2 frequencies. 31 hours at a heavy setting is 10 hours longer than the Forerunner 970's multiband of about 21 hours.
• SUUNTO Race S: JPY 55,000 and 60g on the Japan official site, up to 30 hours with the highest-accuracy GPS. JPY 1,833 per 1 hour (55,000 ÷ 30).

Who is it for?

• Who it suits: People who want to run long mountain races without worrying about battery.

If you do only fulls and halves and your current watch lasts 6 hours, it is soon enough once you use it up. The Ultra 4's outdoor workout is up to 18 hours, enough for a full. It falls short from mountain races beyond 21 hours. If you will not enter 100 miles, the 41-hour PACE 4 reaches races up to 33 hours.

FAQ

How many hours of running watch battery do I need for a full marathon?

If you run it in 6 hours, 6 hours is enough. Even the model with the shortest time in the table, 18 hours, covers it 3 times over. Battery starts to separate models from mountain races beyond 21 hours.

Can the Apple Watch Ultra 4 record 100 miles?

It cannot record the whole way. The official outdoor workout time is up to 18 hours (Apple Watch Ultra 4 review). That is about 4 tenths of a 45h30m race (18 ÷ 45.5). There is also a figure of up to 84 hours in Low Power Mode, but that is time under normal use, not a figure for recording continuously with GPS.

Is a power bank enough for charging my watch during a race?

It is safer not to count on it. Mt.FUJI 100 lists a power bank as mandatory gear. Shinetsu Five Mountains also strongly recommends one. But the main use is for the phone and the light. Choosing a model whose battery exceeds the time limit reduces both baggage and hassle, compared with counting on it for the watch too.

How many hours of battery does multiband cost?

On the Forerunner 970, about 26 hours becomes about 21 hours. For a full marathon, any setting leaves plenty. In a 24-hour race, you must drop to GPS mode (about 26 hours) or it falls short.

Gear in this article

Ads and images: Rakuten Ichiba

Polar PacerAmazfit smartwatchCOROS PACE 4Amazfit BalanceGarmin Forerunner 170COROS APEX 4Garmin EnduroGarmin Instinct 3 Dual Power

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