Garmin Forerunner 645 vs Garmin Forerunner 935 – Which One Is Better

Garmin Forerunner 645 vs Garmin Forerunner 935 – Which One Is Better

Key Update: The Garmin Forerunner 945 is about to be released (June 15 2019). You can find the Forerunner 645 vs Forerunner 945 product comparison here

Before we dive into the finer details, I want to outline a few of the most significant differences between the Forerunner 645 and the Forerunner 935.

Forerunner 645 – Built For Runners – This is primarily a running watch. While it does have indoor swimming and cycling modes, it is best suited for people who focus almost exclusively on running. If you are a 5k, half marathon, or even an ultra marathon specialist, this watch will give you everything you need and more.

Forerunner 935 – Built For Triathletes – The FR935 is perfect for triathletes. In fact, it is one of the best triathlon watches that has ever been made. It basically gives you all the functionality of the Garmin Fenix 5, in a slightly slimmer frame, for a much more affordable price. It also comes in a bundle which includes the Garmin HRM strap, which is essential if you want the best possible heart rate data when swimming, running and cycling.

Forerunner 645 – Music Playback – The Garmin Forerunner 645 Music was the first Garmin watch to introduce in-built music storage. It gives you 3.5 gigabytes to play with, which works out to about 500 songs. The Forerunner 935 doesn’t include music playback, but it makes up for it with better multisport functionality and triathlon specific features.

Now let’s see how these 2 watches stack up against each other technically. To do this, we are going to look at the key similarities, and the key differences between the two watches.

Forerunner 645 vs Forerunner 945 -Key Similarities

GPS + Glonass

Wrist-based HRM

Data Transfer



Control Music on Phone

Smartphone Notifications

V02 Max Estimator

Indoor Swimming Tracking

Barometric Altimeter

Cycling Tracking

Advanced Running Dynamics

With Accessory

With Accessory

Garmin Running Power

With Accessory

With Accessory

Forerunner 645 vs Forerunner 935 - Key Differences

Built-in Music Storage

Contactless Payments

Multisport (Triathlon) Mode

Open Water Swimming

Battery Life

Up to 14 Hours GPS/5 Hours GPS + Music

Up to 24 Hours GPS/Up to 50 Hours Ultratrac GPS




Golf Mode

Visual Summary of Features

Forerunner 645 Key Features

Forerunner 935 Key Features

Why you should consider the Forerunner 935:

To cut a long story short, triathletes across the world are opting for the Garmin Forerunner 935 as their first choice multisport training watch. It quite literally has everything you need to conquer Ironman triathlons with ease. The fact that it comes bundled with 2 HRM straps merely confirms that Garmin knows exactly which persona they are targeting, namely competitive triathletes.

For instance, it has a quick release mechanism which allows you to move the watch from your wrist to your bike mount (after your swim) and then back to your wrist for the run. During a competitive triathlon, this simple release mechanism makes it much easier to manage your watch during all phases of the race, without losing time or expending mental energy.

It is also the only Forerunner which includes a Golf mode. While this only applies to a small segment of the population, it’s worth keeping in mind if you do enjoy playing 18 holes regularly.

Why you should consider the Forerunner 645:

Again, Garmin knows who they are trying to serve with this watch. It’s designed for running specialists who don’t necessarily need open water swim tracking and triathlon features. The music functionality and contactless payments means that there really is no need to carry your phone when you hit the tarmac or the trails.

The only slight drawback to the FR645 is that there are cheaper Garmin alternatives that are especially attractive if you aren’t interested in the built-in music storage or the contactless payments. For instance, the Forerunner 235 offers many of the same features, and often sells for up to $200 less.

If money was no object, which one would I buy?

Personally, I would opt for the Forerunner 935. Here are the main reasons why:

  1. I think it’s better looking: This might sound vacuous, but in the world of wearable tech, looks matter. The FR 645 is also good looking, not it’s not quite as delicious as the 935, in my opinion.
  2. I happen to play golf: The 935 is the only Forerunner that has a golf mode. For a golfer, this is a massive bonus. For a non-golfer, it’s basically meaningless.
  3. The battery life is better: Charging smartwatches is always a mission. The more life I can get from a single charge, the better.
  4. It’s a better multisport watch: Simply put, the Forerunner 935 dominates the 645 in terms of multisport features. It does this mainly through open water swimming, triathlon mode and golf mode. That’s a lot more tech on the table. It just is.

All that being said, the Forerunner 645 is still a very good option for runners. If you’re not into triathlons, and you don’t play golf, it’s pretty much perfect. In many ways, you could call it a Fenix 5 Plus, for runners. The music storage and the contactless payments make that comparison perfectly apt.

Final Thoughts:

The FR645 is arguably the best GPS running watch that money can buy. It literally has everything a runner needs, and it has two massive selling points that the Forerunner 935 can only dream of (music storage and payments).

However, the FR935 is a multisport beast that will comfortably meet the needs of the best triathletes in the world. It’s one of the best multisport GPS watches that has ever been made, and it even dominates the mighty Fenix 5 in terms of value for money.

Ultimately, the Forerunner 935 is my pick, but if you’re not into triathlons and running is your primary sport, the Forerunner 645 is the better option.