Best Running Watch, including Garmin, Polar, & Suunto

As of Jan 2018, I'm no longer actively reviewing watches, but this page will remain accessible as a point in time reference. The "what to look for in a running watch" remains valid and I'd recommend understanding the limitations of GPS for running. I'd recommend checking out [1] for a fairly unbiased opinion, but you should read my review of Stryd footpod as that remains one of the most useful devices for measuring pace and distance. I would suggest avoiding "pseudo-marketing" sites that proport to being detailed reviews without providing any critical thinking. A good litmus test is to check what they say about GPS Accuracy – if they say "it's all good" then you'll know it's just marketing.

This flowchart is a simple guide to finding the right watch for you. Use it as a starting point, and read the detailed reviews to understand if a watch is really right for you. (Click for a larger version.)

1 What to Look for in a Running Watch

A modern running watch often has a huge number of features, but I think it's best to focus on its ability to answer these basic questions.

• How far did I run? This is probably the key feature that most runners are looking for, and it requires good GPS Accuracy. How much the accuracy of a watch will impact your running will depend on the course. Overall, most watches do pretty well in straight lines, but suffer when things get twisty. My testing is a tough challenge for GPS, so it highlights the differences between the great and the appalling. With the advent of the Stryd footpod that's far more accurate than GPS and doesn't require any calibration, Stryd support is now more important than GPS accuracy.
• How fast am I running? While you can work out your average pace from your distance and time, you'll often want to know how fast you're currently running. Unfortunately, GPS is rather poor at answering this question, so you need a Stryd footpod, or use Pace From A Footpod and a first-generation Footpod. An accurate indication of your current pace is important for any training program that requires running at a specific pace, and for success in racing at many distances.
• Where am I? It's not unreasonable to expect a GPS enabled watch to tell you where you are or how to get back to the start. Navigation varies from a simple compass needle showing the direction to return to the start to a display of the route you've just run or a preloaded course.
• What's my cadence? A display of Cadence is a critical training tool and newer watches are able to use an internal accelerometer to provide Cadence without any accessories. Other watches may need a Footpod or the newer Garmin watches can use the running dynamics heart rate strap. A Cadence alert will help you stay in the right cadence range, and is a useful feature.

There are several additional features to you could consider, though I'd argue none are as important as the above questions.

• Weight. None of these devices weigh enough to have a noticeable impact on running performance, but the weight can be noticeable.
• Size. The size of these devices varies widely, and the larger devices can feel a little bulky, especially if you have a smaller wrist. I've provided the size as the volume in cubic centimeters to give a single number to compare.
• Waterproofing. Even if you don't swim, having good waterproofing is important to prevent your watch being destroyed by the rain or sweat.
• Heart Rate Monitor. Heart Rate is important information when training, though it is important to understand the limitations of heart rate based training. Having a Heart Rate Monitor that will record your heart rate is particularly valuable for evaluating your training.
  • Optical Heart Rate Monitoring is more convenient, but does not work very well.
  • While the chest strap based monitoring is remarkably reliable, you can have problems with chaffing and poor reception in some situations, but there are Fixes for Heart Rate Monitor Problems.
• Data Upload. The ability to record your workout and store it in a training log such as Dailymile or SportTracks is vital. All of the recommended watches here have that ability. I'd strongly advise even a new runner to store their data so that they can look back over the months and years to understand their progress. A watch that can upload to a PC makes recording your workouts much easier.
• Battery Life. How much battery life you need depends on how long you run for. It's best to have a watch that will last quite a bit longer than your longest run. I list the claimed battery life in my table, along with the results of my testing. For my tests, I do everything to maximize battery life without compromising GPS accuracy. That means normal GPS sampling frequency, but no backlight, no map display, and no button presses. I also ensure Bluetooth, WAAS and GLONAS are disabled. I don't test devices that I've had for a while, as the battery tends to degrade over time.
• Charges On The Run. For ultrarunners, one option to use a watch for longer than the built in battery lasts is to charge the watch while running. This involves connecting the cable and carrying a USB battery pack. It's cumbersome, but it can work. A value of "Yes" means that the watch will accept charge while recording and displaying as usual. Some watches have a "yes" with a caveat, such as the display not functioning or difficulty in connecting the cable while wearing the watch. An asterisk after the yes indicates a Garmin device that needs to be set with the USB mode to "Garmin" not "Mass Storage". A value of "no" means that charging is impossible.
• Altimeter. An altimeter will measure the atmospheric pressure and give you altitude. This is more accurate than GPS, but will require calibration to adjust for weather related pressure changes.
• Training Effect. This is a measure of how hard a training run is as a numeric value of 1.0 to 5.0, based on an analysis of Heart Rate Variability.
• Heart Rate Variability. There is a growing interest in the possibility of using Heart Rate Variability (HRV) to evaluate training stress. While only one device will display HRV, there are several that will record HRV for later analysis.
• GPS Pre-cache. Some newer watches will download the predicted positions of the GPS satellites for faster initial acquisition. This pre-cache works remarkably well, and the data is usually downloaded automatically when the watch is connected to the internet. However, the data is only valid for a few days, so after that time the device will fall back to the usual approach of scanning for satellites.

2 Comparison

Here's a table of these features for each of the watches I recommend (all have GPS). I evaluate running watches in three distinct ways. Firstly, you can use a watch on its own, without any kind of Footpod. This is probably the most common way runners use their watch, but you miss out on a lot. The second rating is with a standard Footpod that is available quite cheaply. These Footpod's can be reasonably accurate once the calibrated, but calibration is a little tedious. The final evaluation is with the Stryd Footpod, which is vastly more accurate than any other type of Footpod, or and more accurate than GPS. The table below looks at the score, and the value for money of each watch for each of the three conditions. (I’ve also tested the Apple Watch 3, but I’ve not included it in these tables as it’s not really a running watch.)

Review	With Stryd Score	With Stryd Value for money	With Footpod Score	With Footpod Value for money	Without Footpod Score	Without Footpod Value for money	Price at Amazon.com
Garmin Epix Review	47	4.5	31	3.9	23	3.4
Garmin Fenix 5X Review	47	2.9	32	2.3	24	1.9
Garmin Fenix 3 Review	45	3.8	28	3.1	24	3
Garmin 935 Review	45	3.6	30	3	22	2.4
Garmin Vivoactive HR Review	40	4.9	21	3.8	17	3.8
Garmin 920XT Review	39	4.4	30	4.7	24	4.5
Suunto Spartan Ultra Review	37	2.6	27	2.3	23	2.1
Garmin Vivoactive 3 Review	36	4	19	2.9	15	2.8
Garmin Vivoactive Review	34	5.1	14	3.4	10	3.3
Suunto Spartan Trainer Review	34	3.9	23	3.7	18	3.4
Polar V800 Review	33	2.8	26	2.8	22	2.7
Suunto Ambit2 Review	32	3.9	25	4.3	21	4.5
Suunto Ambit3 Peak Review	32	3.4	29	4.1	25	4.2
Garmin Fenix 2 Review	31	2.9	22	2.7	18	2.5
Suunto Ambit3 Run Review	30	4	27	5.5	23	5.9
Suunto Ambit2 R Review	30	3.5	23	3.8	19	3.8
Garmin 235 Review	28	2.9	20	2.8	12	2
Garmin 620 Review	27	3.8	24	5.1	20	5.6
Garmin 910XT Review	26	3.9	26	6.1	21	6.7
Garmin 310XT Review	25	4.6	24	8.3	18	10
Polar M400 Review	25	4.3	15	4.5	11	4.9
Garmin 225 Review	25	3.8	13	3.1	9	2.9
TomTom Cardio Runner Review	25	3.3	10	2	10	2.5
Polar M430 Review	25	3.2	15	2.9	11	2.7
Garmin 610 Review	24	3.3	20	4.3	14	3.9
Leikr Review	10	1	20	2.5	14	2	Leikr ($380)
Epson SF-510 Review	4	0.7	6	2	6	3
Epson SF-810 Review	4	0.6	6	1.6	6	2.3
Garmin 10 Review	2	0.3	2	0.6	2	0.9

The score is the sum of how well each watch can answer the four basic questions (how far, how fast, where are you, what's your cadence), plus some bonus points.

1. The "How far you've run" will be based on GPS only for "without Footpod" and "with Standard Footpod", but based on Stryd if supported in the "with Stryd Footpod" table..
2. How fast you're running assumes you're using a Footpod if it's supported, otherwise the rating is 0-2 based on GPS accuracy.
3. The "Where are you?" is based on various navigation features such as back to start, breadcrumbs, and preloaded maps. For some watches, you have to turn GPS off to get the benefit of Stryd, so those watches have worse "where are you scores" with Stryd than without.
4. The cadence score uses 1 point for an internal cadence sensor, 2 points for footpod support, 1 point for support from chest strap cadence, and 1 point for cadence alerts.
5. I give 1-2 bonus points for application support, 1-2 bonus points for data upload, 1-2 bonus points for Optical Heart Rate Monitoring, and 0-1 bonus points for battery life.
6. Value for money is the score divided by the price (at the time I last updated the table.) Your needs may be different, so you might weight the different aspects of the watches differently, or be basing your decision on different criteria totally. Hopefully this table will give you a good starting point for your decision.

2.1 Score Breakdown without a Footpod

Review	Score	Value for money6	How far did you run?1	How fast are you running?2	Where are you?3	What's your cadence?4	Bonus Points5	class="unsortable" | Price at Amazon.com
Suunto Ambit3 Peak Review	25	4.2	8	3	6	2	6
Garmin 920XT Review	24	4.5	1	2	7	6	8
Garmin Fenix 3 Review	24	3	2	1	7	6	8
Garmin Fenix 5X Review	24	1.9	1	0	9	6	8
Suunto Ambit3 Run Review	23	5.9	8	3	5	2	5
Garmin Epix Review	23	3.4	0	0	9	6	8
Suunto Spartan Ultra Review	23	2.1	8	2	6	2	5
Polar V800 Review	22	2.7	9	4	3	2	4
Garmin 935 Review	22	2.4	1	0	7	6	8
Garmin 910XT Review	21	6.7	5	3	6	2	5
Suunto Ambit2 Review	21	4.5	4	3	6	2	6
Garmin 620 Review	20	5.6	3	2	2	6	7
Suunto Ambit2 R Review	19	3.8	4	3	5	2	5
Garmin 310XT Review	18	10	7	2	4	0	5
Suunto Spartan Trainer Review	18	3.4	5	3	4	2	4
Garmin Fenix 2 Review	18	2.5	1	0	6	6	5
Garmin Vivoactive HR Review	17	3.8	0	0	2	6	9
Garmin Vivoactive 3 Review	15	2.8	0	0	4	4	7
Garmin 610 Review	14	3.9	3	2	3	2	4
Leikr Review	14	2	5	2	4	0	3	Leikr ($380)
Garmin 235 Review	12	2	0	0	2	2	8
Polar M400 Review	11	4.9	3	1	1	2	4
Polar M430 Review	11	2.7	3	1	1	2	4
Garmin Vivoactive Review	10	3.3	0	0	0	6	4
TomTom Cardio Runner Review	10	2.5	2	1	0	2	5
Garmin 225 Review	9	2.9	1	1	0	2	5
Epson SF-510 Review	6	3	0	0	0	2	4
Epson SF-810 Review	6	2.3	1	0	0	2	3
Garmin 10 Review	2	0.9	0	0	0	0	2

2.2 Score Breakdown with a Standard Footpod

Review	Score	Value for money6	How far did you run?1	How fast are you running?2	Where are you?3	What's your cadence?4	Bonus Points5	class="unsortable" | Price at Amazon.com
Garmin Fenix 5X Review	32	2.3	1	4	9	10	8
Garmin Epix Review	31	3.9	0	4	9	10	8
Garmin 920XT Review	30	4.7	1	4	7	10	8
Garmin 935 Review	30	3	1	4	7	10	8
Suunto Ambit3 Peak Review	29	4.1	8	3	6	6	6
Garmin Fenix 3 Review	28	3.1	2	1	7	10	8
Suunto Ambit3 Run Review	27	5.5	8	3	5	6	5
Suunto Spartan Ultra Review	27	2.3	8	2	6	6	5
Garmin 910XT Review	26	6.1	5	4	6	6	5
Polar V800 Review	26	2.8	9	4	3	6	4
Suunto Ambit2 Review	25	4.3	4	3	6	6	6
Garmin 310XT Review	24	8.3	7	4	4	4	5
Garmin 620 Review	24	5.1	3	2	2	10	7
Suunto Ambit2 R Review	23	3.8	4	3	5	6	5
Suunto Spartan Trainer Review	23	3.7	5	4	4	6	4
Garmin Fenix 2 Review	22	2.7	1	0	6	10	5
Garmin Vivoactive HR Review	21	3.8	0	0	2	10	9
Garmin 610 Review	20	4.3	3	4	3	6	4
Garmin 235 Review	20	2.8	0	4	2	6	8
Leikr Review	20	2.5	5	4	4	4	3	Leikr ($380)
Garmin Vivoactive 3 Review	19	2.9	0	0	4	8	7
Polar M400 Review	15	4.5	3	1	1	6	4
Polar M430 Review	15	2.9	3	1	1	6	4
Garmin Vivoactive Review	14	3.4	0	0	0	10	4
Garmin 225 Review	13	3.1	1	1	0	6	5
TomTom Cardio Runner Review	10	2	2	1	0	2	5
Epson SF-510 Review	6	2	0	0	0	2	4
Epson SF-810 Review	6	1.6	1	0	0	2	3
Garmin 10 Review	2	0.6	0	0	0	0	2

2.3 Score Breakdown with a Stryd Footpod

Review	Score	Value for money6	How far did you run?1	How fast are you running?2	Where are you?3	What's your cadence?4	Bonus Points5	class="unsortable" | Price at Amazon.com
Garmin Epix Review	47	4.5	10	10	9	10	8
Garmin Fenix 5X Review	47	2.9	10	10	9	10	8
Garmin Fenix 3 Review	45	3.8	10	10	7	10	8
Garmin 935 Review	45	3.6	10	10	7	10	8
Garmin Vivoactive HR Review	40	4.9	10	10	1	10	9
Garmin 920XT Review	39	4.4	10	10	1	10	8
Suunto Spartan Ultra Review	37	2.6	10	10	6	6	5
Garmin Vivoactive 3 Review	36	4	10	10	1	8	7
Garmin Vivoactive Review	34	5.1	10	10	0	10	4
Suunto Spartan Trainer Review	34	3.9	10	10	4	6	4
Polar V800 Review	33	2.8	10	10	3	6	4
Suunto Ambit2 Review	32	3.9	10	10	6	0	6
Suunto Ambit3 Peak Review	32	3.4	10	10	6	0	6
Garmin Fenix 2 Review	31	2.9	10	10	6	0	5
Suunto Ambit3 Run Review	30	4	10	10	5	0	5
Suunto Ambit2 R Review	30	3.5	10	10	5	0	5
Garmin 235 Review	28	2.9	10	10	0	0	8
Garmin 620 Review	27	3.8	10	10	0	0	7
Garmin 910XT Review	26	3.9	10	10	1	0	5
Garmin 310XT Review	25	4.6	10	10	0	0	5
Polar M400 Review	25	4.3	10	10	1	0	4
Garmin 225 Review	25	3.8	10	10	0	0	5
TomTom Cardio Runner Review	25	3.3	10	10	0	0	5
Polar M430 Review	25	3.2	10	10	1	0	4
Garmin 610 Review	24	3.3	10	10	0	0	4
Leikr Review	10	1	5	2	0	0	3	Leikr ($380)
Epson SF-510 Review	4	0.7	0	0	0	0	4
Epson SF-810 Review	4	0.6	1	0	0	0	3
Garmin 10 Review	2	0.3	0	0	0	0	2

2.4 Basic Features

Review	Released	GPS Accuracy	Weight (oz)	Size (CM3)	Display (mm)	Resolution (Pixels)	Waterproofing	Heart Rate Monitor	Cadence	Data Upload
Garmin Epix Review	2015	6.2	3.0	48	29 x 21 (609mm2)	205 x 148 (30.3K total)	Good (50m)	Yes	Internal/Footpod/Heart Rate Monitor/Alert	Yes
Garmin Fenix 5X Review	2017	5.6	3.5	36	30.5 (round) (731mm2)	240 diameter (45.2K total)	Good (100m)	Yes	Internal/Footpod/Heart Rate Monitor/Alert	Yes
Garmin Fenix 3 Review	2015	6.2	2.9	33	30 (round) (726mm2)	218 diameter (37.3K total)	Good (100m)	Yes	Internal/Footpod/Heart Rate Monitor/Alert	Yes
Garmin 935 Review	2017	5.6	1.7	24	30.5 (round) (731mm2)	240 diameter (45.2K total)	Good (100m)	Yes	Internal/Footpod/Heart Rate Monitor/Alert	Yes
Garmin Vivoactive HR Review	2016	4.9	1.7	19	21 x 29 (609mm2)	148 x 205 (30.3K total)	Good (50m)	Yes (+OHRM)	Internal/Footpod/Heart Rate Monitor/Alert	Yes
Garmin 920XT Review	2014	6.6	2.2	35	29 x 21 (609mm2)	205 x 148 (30.3K total)	Good (50m)	Yes	Internal/Footpod/Heart Rate Monitor/Alert	Yes
Garmin Vivoactive 3 Review	2017		1.5	17	30.5 (round) (731mm2)	240 diameter (45.2K total)	Good (50m)	Yes (+OHRM)	Internal/Footpod	Yes
Garmin Vivoactive Review	2015	5.4	1.3	13	29 x 21 (592mm2)	205 x 148 (30.3K total)	Good (50m)	Yes	Internal/Footpod/Heart Rate Monitor/Alert	Yes
Suunto Spartan Trainer Review	2017	7.8	2.0	25	24 x 23 (529mm2)	128 diameter (12.9K total)	Good (50m)	Yes (+OHRM)	Internal/Footpod	Yes
Suunto Ambit2 Review	2013	7.6	3.1	30	29 (round) (661mm2)	128 diameter (12.9K total)	Good (100m)	Yes	Internal/Footpod	Yes
Suunto Ambit3 Peak Review	2014	7.9	2.9	30	29 (round) (661mm2)	128 diameter (12.9K total)	Good (100m)	Yes	Internal/Footpod	Yes
Suunto Spartan Ultra Review	2016	7.1	2.7	38	32 (round) (804mm2)	320 diameter (80.4K total)	Good (100m)	Yes	Internal (Limited Footpod)	Yes
Garmin Fenix 2 Review	2014	5.7	3.2	32	31 (round) (755mm2)	70 diameter (3.8K total)	Good (50m)	Yes	Internal/Footpod/Heart Rate Monitor/Alert	Yes
Suunto Ambit3 Run Review	2014	7.9	2.5	30	29 (round) (661mm2)	128 x 128 (16.4K total)	Good (50m)	Yes	Internal/Footpod	Yes
Suunto Ambit2 R Review	2013	7.6	2.5	30	29 (round) (661mm2)	128 diameter (12.9K total)	Good (50m)	Yes	Internal/Footpod	Yes
Garmin 235 Review	2015	4.9	1.5	19	31 (round) (755mm2)	215 diameter (36.3K total)	Good (50m)	Yes (+OHRM)	Internal/Footpod	Yes
Garmin 620 Review	2013	7.1	1.5	20	25.4 (round) (507mm2)	180 diameter (25.4K total)	Good (50m)	Yes	Internal/Footpod/Heart Rate Monitor/Alert	Yes
Garmin 910XT Review	2011	7.5	2.5	49	33 x 20 (660mm2)	160 x 100 (16K total)	Good (50m)	Yes	Footpod/Alert	Yes
Garmin 310XT Review	2009	7.5	2.5	63	33 x 20 (660mm2)	160 x 100 (16K total)	Good (50m)	Yes	Footpod	Yes
Garmin 225 Review	2015	6.2	1.5	24	25.4 (round) (507mm2)	180 diameter (25.4K total)	Good (50m)	Yes (+OHRM)	Internal/Footpod	Yes
TomTom Cardio Runner Review	2015	6.0	2.2	30	22 x 25 (550mm2)	144 x 168 (24.2K total)	Good (50m)	Yes (+OHRM)	Internal/Footpod	Yes
Polar V800 Review	2014	8.0	2.8	31	23 x 23 (529mm2)	128 x 128 (16.4K total)	Good (30m)	Yes	Internal/Footpod	Yes
Polar M430 Review	2017	7.2	2.0	24	23 x 23 (529mm2)	128 x 128 (16.4K total)	Good (50m)	Yes (+OHRM)	Internal/Footpod	Yes
Polar M400 Review	2014	6.6	2.0	24	23 x 23 (529mm2)	128 x 128 (16.4K total)	Good (30m)	Yes	Internal/Footpod	Yes
Garmin 610 Review	2011	7.3	2.5	41	25.4 (round) (507mm2)	128 diameter (12.9K total)	Fair (IPX7)	Yes	Footpod/Alert	Yes
Leikr Review	2013	7.3	2.4	25	41 x 31 (1271mm2)	206 x 148 (76.8K total)	Fair (IPX6)	Yes	Footpod	Limited
Epson SF-510 Review	2015	4.4	1.7	24	28 x 22 (616mm2)	128 x 96 (12.3K total)	Good (50m)	Yes	Limited Internal	Limited
Epson SF-810 Review	2015	5.5	1.8	28	28 (round) (616mm2)	128 diameter (12.9K total)	Good (50m)	OHRM Only)	Limited Internal	Limited
Garmin 10 Review	2012	3.8	1.3	33	25 x 24 (600mm2)	55 x 32 (1.8K total)	Good (50m)	No	No	Yes

Review	Battery Life (hr)	Tested Battery Life (hr)	Extended Battery Life (hr)	Charge On The Run?	Training Effect	HRV	GPS cache	Sensors
Garmin Epix Review	24	17.6	50	Yes (with USB=Garmin)	Yes	Record	Yes	Ant+
Garmin Fenix 5X Review	20	23	35	Yes, but can't be worn	Yes	Record	Yes	Bluetooth/Ant+
Garmin Fenix 3 Review	20	22	50	Yes (with USB=Garmin)	Yes	No	Yes	Ant+
Garmin 935 Review	24	24.5	60	Yes, but can't be worn	Yes	Record	Yes	Bluetooth/Ant+
Garmin Vivoactive HR Review	13		13	Yes (with USB=Garmin)	No	No	Yes	Ant+
Garmin 920XT Review	24	19	40	No (terminates)	Yes	Record	Yes	Ant+
Garmin Vivoactive 3 Review	13		13		No		Yes	Bluetooth/Ant+
Garmin Vivoactive Review	10	10	10	Yes (with USB=Garmin)	No	No	Yes	Ant+
Suunto Spartan Trainer Review	10	11	30	Yes	Yes	No	Yes	Bluetooth
Suunto Ambit2 Review	15		50	Yes	Yes	Record	Yes	Ant+
Suunto Ambit3 Peak Review	20		100	Yes	Yes	Record	Yes	Bluetooth
Suunto Spartan Ultra Review	18	17	26	Yes, but can't be worn	Yes	Record	Yes	Bluetooth
Garmin Fenix 2 Review	15		50	Yes (with USB=Garmin)	Yes	No	Yes	Ant+
Suunto Ambit3 Run Review	10	10.5	100	Yes	Yes	Record	Yes	Bluetooth
Suunto Ambit2 R Review	8	7.3	25	Yes	Yes	Record	Yes	Ant+
Garmin 235 Review	11		11	Yes, but no optical HR	Yes	No	Yes	Ant+
Garmin 620 Review	10		10	No (resets)	Yes	Record	Yes	Ant+
Garmin 910XT Review	20		20	Yes, but no display	Yes	Record	No	Ant+
Garmin 310XT Review	20		20	Yes, but no display	No	No	No	Ant+
Garmin 225 Review	10	11	10	No (resets)	No	No	Yes	Ant+
TomTom Cardio Runner Review	8	6.3	8	No (resets)	No	No	Yes	Bluetooth HR
Polar V800 Review	13	24	50	No (terminates)	Yes	Display	Predictive	Bluetooth
Polar M430 Review	8	8	8	No	No	No	Yes	Bluetooth
Polar M400 Review	8		8	Yes, but can't be worn	No	No	No	Bluetooth
Garmin 610 Review	8		8	Yes, but no display	Yes	Record	No	Ant+
Leikr Review	5	6.5	5	Yes, but can't be worn	No	No	Yes (few hours)	Ant+
Epson SF-510 Review	30	30	30	No	No	No	Yes (few hours)	Bluetooth HR
Epson SF-810 Review	20	26	20	No	No	No	Yes (few hours)	None
Garmin 10 Review	5		5	No	No	No	No	None

3 Navigation Features

Review	Color Maps	Breadcrumbs	Courses	To Waypoint	Compass	Reverse course	Beeline to start	Connect IQ	Altimeter
Garmin Epix Review	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes
Garmin Fenix 5X Review	Yes	Yes	Yes	Yes	Yes	Yes	No	No	Yes
Garmin Fenix 3 Review	No	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes
Garmin 935 Review	No	Yes	Yes	Yes	Yes	Yes	No	No	Yes
Garmin Vivoactive HR Review	No	No	No	No	No	No	No	Yes	Yes
Garmin 920XT Review	No	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes
Garmin Vivoactive 3 Review	No	No	No	No	No	No	No	No	No
Garmin Vivoactive Review	No	No	No	No	No	No	Yes	Yes	No
Suunto Spartan Trainer Review	No	No	No	No	No	No	Yes	No	No
Suunto Ambit2 Review	No	No	Yes	Yes	Yes	Yes	Yes	No	Yes
Suunto Ambit3 Peak Review	No	No	Yes	Yes	Yes	Yes	Yes	No	Yes
Suunto Spartan Ultra Review	No	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes
Garmin Fenix 2 Review	No	Yes	Yes	Yes	Yes	Yes	No	No	Yes
Suunto Ambit3 Run Review	No	No	Yes	Yes	Yes	Yes	Yes	No	No
Suunto Ambit2 R Review	No	No	Yes	Yes	Yes	Yes	Yes	No	No
Garmin 235 Review	No	No	No	No	No	No	Yes	Yes	No
Garmin 620 Review	No	No	No	No	No	No	No	No	No
Garmin 910XT Review	No	Yes	Yes	Yes	No	Yes	Yes	No	Yes
Garmin 310XT Review	No	Yes	Yes	Yes	No	Yes	No	No	No
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For "navigation":

• Color Maps gives you full color maps, rather like a smart phone, with roads and paths marked out.
• Track Outline is a display of where you've run, rather like a breadcrumb trail. If there are maps, the outline is superimposed otherwise this is just the outline on its own without any context.
• Course Outline is an outline of a route that can be downloaded. I've found this useful during ultras or in unfamiliar cities where I've needed to know where to go.
• Back To Start is a simple arrow point to your starting point, so it won't help you backtrack.
• Back To Waypoint returns you to a previously marked location using a simple arrow to point.
• Compass. A magnetic compass can help you orient yourself or the map. Without a magnetic compass you have to be moving for the GPS to give you a sense of direction.

(Older Reviews: Polar RC3 GPS, Soleus 1.0, Motorola Motoactv.)

4 GPS Accuracy

An infographic of GPS Accuracy of running watches. The top right corner represents the most accurate watches. (This graphic uses ISO 5725 terminology.)

5 Using a Smartphone

Main article: Running With A Smartphone

Most smartphones have a GPS built in and support various applications that allow them to function as sports watches. These phones can have remarkable levels of GPS Accuracy as well as many other advantages.

6 Watches for Ultrarunning

Choosing a watch for an ultramarathon requires some tradeoffs and there's no simple answer. The main factor is battery life, as few watches can be relied on to lost more than 20 hours with GPS active. I think there are three main approaches to this problem:

1. Charge On The Run. This is a little cumbersome as you typically have to carry a battery pack and an adapter, or at least have them in your drop bag. Not all watches support Charge On The Run, and only a subset of them do so with reasonable convenience.
2. Use two watches. This is also rather inconvenient and expensive, though you may be able to use to cheaper watches rather than one more expensive watch. For the second part of your run, the second watch won't have your full time and distance, so you'll need to make a note from the first watch and do some math. (Doing math late in an ultra is as difficult as it sounds.)
3. Extended battery life. A number of watches allow you to reduce the GPS accuracy to gain greater battery life. This lack of accuracy can be offset by using the Stryd Footpod for the first part of the race (they claim that Stryd lasts 20 hours.) Another approach is to turn the GPS off entirely and rely on a first generation Footpod, in which case many watches will last several days. While the accuracy of a first gen Footpod can be better than GPS, the Footpod does not do so well if you're taking Walking Breaks or running on twisty single track.

And some runners will want navigation. I see three main approaches to I wish I could provide, simple, clear cut advice, but unfortunately things are not so easy. You'll need to think about how long you'll be running for, the features that are important to you, and how much compromise you can live with.

Charge On The Run is an option for ultras.

6.1 Battery Life

• The claimed battery lives don't hold up in the real world, with some watches going longer, others much shorter.
• If you want the maximum battery life, you have to avoid the backlight, the use of map/course displays, and don't press the buttons unless you have to.
• In my testing, the longest battery life that's available with GPS on is 30 hours with the Epson SF-510, 24 hours with the Polar V800, 22 hours with the Garmin Fenix 3, 19 with the Garmin 920XT, and 17 with the Garmin Epix.
• For ultras lasting less than 20 hours, such as 50 miles or 100 Km, you have plenty of choice and battery life should not constrain you too much.
• For 24 hour races or 100 mile races where you expect a finish in the 24-30 hour range the Epson SF-510 is worth considering though the battery life is one of its few good points.

6.2 Navigation

For some ultras (and shorter trail runs), navigation is a problem. I've been lost on the occasional race and it's a horrible experience. Even when I've been on course, the doubts and stress of worrying can be an enormous drain. My first GPS watch was purchased so that I'd have an outline of the course I was running and there were many races where I was glad of its comforting conformation. Remember that using the navigation features of these watches will dramatically reduce their battery life.

• The Garmin Fenix 5X and the Garmin Epix have a display that shows full color maps, so for navigation, nothing else comes close. (Well, the Leikr is even better, but it has a short battery life.)
• The Garmin 310XT, Garmin 910XT, Garmin 920XT, Garmin Fenix 3, Suunto Spartan Ultra will show an outline of your run (breadcrumbs) and allow you to load a course outline to follow.