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Garmin Forerunner 645 Versus Forerunner 935, Fenix 5 & Vivoactive 3

The recently released Garmin Forerunner 645 has mainly been notable thanks to its ‘Music’ version which offers on-board storage of up to 500 songs. Otherwise, the 645 is a nice upgrade from the Forerunner 630 but hard to differentiate from some of Garmin’s other watches — namely the Forerunner 935, Fenix 5, and the Vivoactive 3. We’ve compiled this comparison of those watches to help you decide which Garmin sports watch is right for you.



These four sport watches are fairly close in price, with the exception of the Vivoactive 3, which is at least $100 less than its siblings. The Forerunner 645 comes in at under $400 unless you add the music option, which brings it up by roughly $40.

The Forerunner 935 and Fenix 5 are priced very similarly (around $450-$500) but the Fenix 5 has much more of a range depending on the model you’re looking at. It goes up to $700 for premium versions.

The Vivoactive 3’s regular price is just under $300.


The Forerunner 645 and Vivoactive 3 are slightly more conventionally designed when compared to the other two, but all four have a solid design that will appeal to most. None of these have any particulars that make them unappealing in general (compared to some other watches that try too hard to be fashionable). They all have a rounded face, solid straps that can be changed out, and nice-looking screens.

The Vivoactive 3 is more of a smartwatch than a sports watch, and it has a vibrant screen and is very lightweight.

The FR 645 is similar in size to the Vivoactive. It’s easy to read even in bright sunlight, and it’s got some nice options for different screen looks. As we reported in our full review, there isn’t much to report in design changes between the 645 and others in the Forerunner lineup.

Those who love the design of the FR 935 and the Fenix 5 tend to be those who love the durable feel and rugged looks of the two premium watches. Both are built for hardcore athletes, so both offer some extras that make it built for extreme sports — plus the Fenix 5’s premium versions offer even better support and durability with a sapphire screen and more.


No matter which one you buy, you’ll get a few of the basic features, including:

  • Onboard GPS
  • Water Resistance
  • 24×7 Heart Rate Monitoring: Zones, Alerts, Calories
  • Activity Tracking: Steps, Calories, Distance, Floors, and more
  • Sleep Monitoring
  • Stress Monitoring

The FR 935 and Fenix 5 excel in multisport and triathlon tracking, so those two are the preferred watches for some athletes. The Vivoactive 3 and FR 645 are better suited for runners, cyclers, and swimmers (though they do not support open water swims). It’s worth paying more for either the 935 or Fenix if you have the money and/or if you have a need for a more robust sports watch. The Fenix 5 is the most durable watch, built expressly for standing up to outdoor adventures.

Head to Head Comparisons

Forerunner 645 vs. Vivoactive 3

The Vivoactive 3 has a touchscreen; the 645 uses button navigation only. The 645 has more advanced metrics for runners and it has the option for built-in music for $40 more. Overall, the FR645 feels more like a sports watch and the Vivoactive 3 feels more like a smartwatch. They have similar battery life (around 7 days; 13 hours in GPS mode) and very similar weight and dimensions. The Vivoactive 3 has golf support, but the 645 does not. And then there’s price — the Vivoactive is a lot less expensive. Our full review of the Vivoactive 3 is here.

Choose the Vivoactive 3 if you want to pay less or if you primarily want a smartwatch with some fitness tracking. Also, choose the Vivoactive if you want golf support or touchscreen. See the current price here.

Choose the 645 if you’ll use advanced running metrics or you want the built-in music feature.

Forerunner 645 vs. Forerunner 935 & Fenix 5

Here’s the thing: The only reason we would recommend the 645 is if either the non-music version fits your budget better or you want the music version specifically. Otherwise, it’s well worth the extra to get the Forerunner 935. The 935 is frequently marked down to under $450, so it’s not much more and you get so many more features. The only thing it lacks is Garmin Pay (NFC contactless payments), but that feature has been buggy at best on the 645 anyway. See the current price on the FR 935.

And, of course, we love the Fenix 5, but that’s really only worth the additional money if you need the extra protection and durability. The Fenix 5 lineup is made up of nice looking watches, so it might be worth saving up for if you love the look of them as much as we do.

Related: Check out our full reviews of the best Garmin watches and fitness trackers

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