garmin fenix 3 hr vs forerunner 735xt

Garmin Forerunner 735XT vs Fenix 3HR – Best Triathlon Watches 2017

For runners and other sports enthusiasts, GPS watches have become a popular tool to track activities, improve performance, and show off some technological bling. Garmin, a leading producer of GPS watches for athletes, currently has several models available – but which one is best for your training?

Best Garmin Triathlon & Multisport Watches 2017

For triathletes, runners and other sports enthusiasts, GPS watches have become a popular tool to track activities, improve performance, and show off some technological bling. Garmin, a leading producer of GPS watches for runners and triathletes alike, currently has several models available – but which one is best for your next triathlon?

This article will explore the Garmin Forerunner 735XT, a popular running and multisport watch and the Garmin Fenix 3HR, an 'outdoor' GPS multisport watch. We'll also touch upon older models such as the Forerunner 920XT for a comparison.

Best Garmin Watches for Triathletes - Personal Recommendations

While the Forerunner 735XT and Fenix 3 HR are similar in many ways, there are some very noticeable differences between them. Here is a basic highlight of each watch and how they differ from each other.

best garmin triathlon watch - forerunner 735xt

Garmin Forerunner 735XT

Are you a triathlete or runner looking for a lightweight sports watch that you can use for training or during an event? Forerunner 735XT is ideal. It's extremely lightweight (40.2g) and will easily fit under a tri suit or long sleeve compression top. 735XT has wrist-based heart rate and detailed measurements for running and cycling and swim workouts. The most important feature for triathletes will be the auto multisport feature which will let you transition sports seamlessly with one button.


  • Lightweight with slim form factor (40.2g)
  • Advanced running and cycling dynamics for detailed feedback on form
  • Wrist-based heart rate for heart rate zones during activity
  • HRM-Tri and HRM-Swim compatible


  • Lacks activity memory and outdoor GPS features such as backtracking and ABC
  • Plastic design lacks elegance or style

Garmin Fenix 3 HR

There are several versions of the Fenix 3 HR now available with different interchangeable watch bands to match your style. The Garmin Fenix 3HR Sapphire Grey with Black Silicone Band (Amazon) would be best suited to triathletes and runners.

garmin fenix 3 hr best triathlon watches

These watches have so many features from 2nd generation running dynamics and physiological measurements to automatic calibrating altimeter, barometer and 3-axis compass. The Fenix 3 HR (Amazon) looks as good as it performs and can easily be worn as a stylish wrist watch when you're not running up a mountain (or skiing down one).


  • A true multi-sport watch that can track running, swimming, cycling, hiking, skiing and much more
  • Great battery life with up to 16 hours in GPS mode or 40 hours in UltraTrac mode
  • Wrist-based HR measurement provides accurate time in zones and calorie burn for activities
  • Stylish, rugged design, suitable for all-day wear with total daily stats such as step count and calorie burn


  • Falls on the higher end of the GPS watch price range
  • Heavy and chunky design (86.1g with silicone band)

Common Garmin Triathlon Watch Features

The Forerunner 735XT (Amazon) and Fenix 3HR (Amazon) have many basic features in common. First and foremost, these are both GPS tracking watches. That means these watches will track your activity route and provide an accurate summary of distance, pace, time and even a map via Garmin Connect app.

Both of these GPS watches are “multi-sport” in that they can be used to track running, cycling, and swimming activities. Both also include wrist-based heart rate monitoring, which allows the user to receive a very accurate calorie burn estimate for activities. Further, these watches can be worn all day like a regular watch and provide the user with daily stats such as total step count, calories burned, and more.​

Forerunner 735XT - transition seamlessly to your next sport

forerunner 735xt transition during triathlon

Tech Specs

garmin forerunner 735xt triathlon and running watch
Forerunner 735XT​
  • Physical dimensions: 1.75" x 1.75" x 0.47"
  • Weight: 1.4 ounces (40.2 g)
  • Water rating: 5 ATM
  • Display size: 1.23" diameter
  • Display resolution: 215 x 180 pixels
best watch for triathletes - garmin fenix 3 hr
Fenix 3 HR
  • Physical dimensions: 2.0" x 2.0" x 0.6"
  • Weight: 3 ounces (86.1 g)
  • Water rating: 10 ATM
  • Display size: 1.2" diameter
  • Display resolution: 218 x 218 pixels

Feature comparison

While these two GPS watches have some basic functions in common, there are several differences between the two models. Most notably, the Forerunner 735XT is primarily a running watch, while the Fenix 3HR is a true multi-sport watch. This means that the Forerunner’s features are focused around tracking runs, while the Fenix acts more broadly and is able to track a multitude of sports and activities.

The Fenix 3HR also has more features in general than the Forerunner 735XT. The Fenix has greater memory capabilities, with the ability to store routes, points of interest, and up to 100 hours of activity data. The Forerunner, on the other hand, can store only 80 hours of activity data and no other information.

The Fenix boasts additional features that make it feel "smarter" than the Forerunner: the Fenix's barometric altimeter allows the user to receive weather alerts, the compass allows navigation including backtracking, and the clock boasts additional features such as alarms and a sunrise/sunset reminder.​

Overall, when it comes to the Garmin Forerunner 735XT vs Fenix 3HR, the Fenix is a more advanced multi-sport tracking tool with more features and options. The Forerunner is better suited to runners and cyclists and not hikers who need ABC navigation.

Style comparison

The Forerunner 735XT is a smaller and lighter watch than the Fenix 3HR. In fact, it’s quite impressive that Garmin managed to fit a wrist-based heart rate device in such a small watch. The extra features of the Fenix 3HR cause it to weigh more than double the Forerunner 735XT.

Apart from size, there are differences in the style and color varieties of each watch. Starting with the Fenix 3HR: unfortunately, there isn’t much variety here at all. The Fenix is available in only one color scheme, which is a dark grey metallic watch face and a black wristband (other colors available separately). This neutral color palette would look good with most clothing, and is suitable for both men and women, it's a stylish design and may look sharp enough for a professional setting.

The Forerunner 735XT does offer two different color options. The first model is similar to the Fenix, with a black watch face and black-and-gray wristband. The other model available is much more colorful, with a “frost blue” wristband and blue accents on the watch face.

When it comes to style and design in the Garmin Forerunner 735XT vs Fenix 3HR, the Forerunner wins for it’s more discreet size and weight which will be better for many athletes.

garmin forerunner 735xt triathlete watch

Forerunner 735XT - lightweight and compact


GPS sport watches are not known for being cheap, but the upside is that they should last a very long time and provide many benefits to the user. With that in mind, know that both of these watches will cost customers several hundred dollars to purchase.

While these watches can both be purchased directly from Garmin, check out Amazon for a potentially lower price. Either way, customers can expect to pay about $100 more for the Fenix 3HR than the Forerunner 735XT. That’s a big difference!

Forerunner 735XT vs Fenix 3HR Bottom Line

When it comes to the Garmin Forerunner 735XT vs Fenix 3HR, it’s hard to choose a solid winner. These triathlon watches have many of the same features, but it really depends on your use and your training.

Are you looking for a lightweight, small, GPS running watch? Then the Forerunner 735XT is for you. On the other hand, if you want a multi-sport tracker with all the bells and whistles, go ahead and spring for the Fenix 3HR. You’re sure to be happy with either purchase!

Related Triathlon Watches:

Last update on 2021-10-26 / Affiliate links / Images from Amazon Product Advertising API

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