Garmin Forerunner 935 review: After 1,000 miles, our expert won't run with anything else

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Garmin's Forerunner fitness trackers have long been one of the brand's most popular among serious runners. Not only do they offer unique running data and tailored feedback but they're designed to fit, feel, and function exactly the way a runner needs it to.

One of Garmin's most advanced Forerunners is the Forerunner 935, a fitness watch designed with marathon runners and triathletes in mind.

To put this watch to the test, we asked competitive distance runner, Ted Westbrook, to sport it for at least 1,000 cumulative miles of running workouts. Westbrook has over a dozen years of experience using some of the best fitness trackers and is no stranger to utilizing fitness trackers in his training. 

After three months of using the watch — both in training and in races — Westbrook told Insider the Forerunner 935 is "far and away the best training tool I've ever used." Below is a closer look at Westbrook's experiences with the watch and why we ended up picking it as one of the best running watches you can buy. 

A mid-size watch with premium features

The Forerunner 935 is a mid-sized watch that may feel a bit big for folks with small wrists. It is, however, lightweight (49 grams) and comfortable to wear. The band, which is made of a slightly stretchy rubberized plastic, is an improvement in comfort over its predecessor, the 920XT.

The watch face is protected by tempered glass that's scratch-resistant (something Westbrook experienced often), which is another substantial improvement over the previous generation.

In addition to providing real-time feedback like pace and distance, the 935 also features an integrated optical heart rate monitor that proved to be both accurate and quick to sync. It also allows you to set target heart rates when you work out, too, which Westbrook found particularly useful for easy-effort runs where his goal was active recovery and not to over-stress his body.

The 935 is waterproof to 5 ATM and has a mode entirely devoted to swimming that keeps accurate stroke counts. Cyclists will appreciate being able to use it as a cycling computer as well, as it has devoted outdoor and indoor cycling modes. Westbrook also commented on how beneficial the dedicated triathlon mode is which tracks each leg of the event, providing custom information for each sport, along with transition times. 

It offers a wealth of fitness metrics at your fingertips

The Garmin Forerunner 935 collects and displays all your workout data and makes it easy to customize the watch face to show exactly what you want to see. While running, Westbrook wanted it to show three or four different parameters simultaneously, and each one was clearly readable. This included lap pace and distance, as well as his current heart rate and zone.

Westbrook loved this functionality: "I have one screen I use most of the time and a second that's available at the push of a button for data that's more specific to running interval workouts, like lap time and lap distance. Customization is easy and intuitive."

It's highly accurate both with and without GPS

Whether on an indoor track or treadmill, the watch maintains solid functionality via indoor running modes that use the watch's precise accelerometers to estimate pace and distance. While generally less accurate than using GPS outdoors, Westbrook confirmed that the non-GPS mode still provides accurate data to within a small difference of each other, which is remarkably good.

Many of the 935's advanced features are accessible post-run through the Garmin Connect app. This is where Westbrook found the 935 to be truly unique. He was able to geek out on his data analytics and use the information to adjust his training schedule or pacing. 

Westbrook found that the 935's VO2 max monitor was also a helpful tool for his training. With this active, the watch takes heart rate, pace, and distance data and combines it with information about height, weight, age, sex, and maximum heart rate to estimate a VO2 max reading and lactate threshold.

These are two of the most important metrics of running fitness and potential and provide valuable information for serious runners and can give indications of whether your overall training is productive or unproductive. 

It's not a perfect watch and does have a few drawbacks

Many, if not all, of the advanced training functions of the 935 and Garmin Connect rely on assumptions and formulae that aren't always going to produce accurate results. At one point, the Race Predictor feature of the 935, relying on calculations of VO2max from Westbrook's running and personal data, predicted that he could run a marathon in two hours and 28 minutes.

Westbrook told us, "This was flattering but about 7% faster than reality." VO2 max can only truly be measured in a lab environment and the readings done by the 935 aren't supposed to be used as absolute fact. They're designed mostly to provide an informal snapshot of your training progress. 

Additionally, the battery lasts roughly 24 hours on a single charge with GPS active. Westbrook often got more than this since he wasn't using GPS every hour of the day but did still have to charge the watch every other day. This is something to note as 24 hours is on the shorter side compared to other multisport watches like the Garmin Epix. 

Revisiting the 935, one year later

Garmin's line of Forerunner watches is extensive, with a model designed quite literally for every kind of active user. The Forerunner 745, for instance, is one of the brand's mid-range options offering unique insights into rest and recovery, while also providing similar access to a variety of trackable activities, wellness features, and advanced data tracking. 

Another option is the Forerunner 55, a more budget-friendly model that's smaller in size, offers battery life of up to two weeks, and is a more basic, entry-level pick. 

Then there's the Forerunner 935 here. This advanced running watch remains best used by those training for events like a marathon or triathlon. Westbrook may have run 1,000 total miles to initially review the watch for us, but it's logged countless more since and continues to hold up both in terms of durability and function — and you'll find that same quality and utility on any Forerunner watch Garmin sells. 

Should you buy it?

Depends. With all the advanced data available — which is often most useful for high-mileage competitive distance runners who are out on the pavement or track every day — it's fair to question whether a new or occasional runner should go for a lower-shelf model than the Forerunner 935.

It may also be worthwhile to consider a different fitness tracker like one of the best Fitbits or one of the best Apple Watches if running is only one of many activities you plan on doing.

While the answer could depend on one's budget and just how much of a runner they want to be, new runners are likely to appreciate how well the 935 does the basics of near-instant GPS acquisition, pace, distance, and heart rate. When they're ready, the more advanced data analytics would still be there when they want them.

A beginner isn't going to outgrow the 935, and the basics are intuitive enough in use that they won't intimidate anyone who is used to dealing with smartphones. The 935 is an investment that pays dividends in fitness motivation and hardcore data.

We asked Westbrook if he would continue to use the 935 once done testing it. He said, "Most certainly. And, I would buy another if this one got lost."