It’s been almost accurately per month since Garmin announced their latest triathlon watch, the Forerunner 735XT. This watch aims to take the program of the bigger FR920XT triathlon watch and compress it into a smaller package. All while also adding in optical heartrate sensor and other new software features.

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as of May 16, 2022 9:18 pm
as of May 16, 2022 9:18 pm
as of May 16, 2022 9:18 pm
Last updated on May 16, 2022 9:18 pm

I’ve now been using the machine for about per month in my daily training and racing. Not merely has it done typical swim/bike/run workouts, but I’ve also used it in two different triathlon races. Thus, I’m pretty acquainted with what is effective and which parts remain a little wonky.

Note that I’ve two units. One which Garmin delivered to trial, and another that I found as a standard consumer. I’ve mostly been using the main one I found myself, while I’ve also done several face to face tests to see if there are any dissimilarities (such as for example in battery life and other accuracy areas). As is often the case, once I’m finished with the machine here shortly I’ll ship the loaner back again to Garmin. You can support the blog page using the links by the end of the review.

The Quick Review Version:

As I really do every once in a rare while, I’m likely to offer somewhat of an executive summary of my review here. Obviously, I can’t fit everything into this section. But I’ll cover the main element things in the shortest possible section. First, let’s briefly cover in bulleted form what’s different or unique about the FR735XT in comparison to other Garmin multisport units.

  • Adds in Varia Vision support (first Garmin wearable to aid the heads-up display)
  • Adds in Garmin Varia Radar & Varia lights support
  • Adds in Shimano Di2 electronic gear shifting
  • Adds in support for structured swimming workouts (via Garmin Connect)
  • Adds in Lactate Threshold metrics while running (on Fenix3, however, not FR920XT)
  • Adds in FTP determination while cycling (on Edge series, however, not FR920XT)
  • Adds ‘Intensity Minutes’ metrics (seen on other Garmin activity trackers)
  • Adds Strava Suffer Score (new on FR735XT)
  • Adds phone-based audio tracks prompts (introduced on FR230/235/630)
  • Adds stress score (introduced on FR630, now on Fenix3, however, not FR920XT)
  • FR735XT officially 14hr GPS battery life, significantly less than that of FR920XT/Fenix3
  • Lacks a barometric altimeter that’s on FR920XT & Fenix3 (but nonetheless has GPS altitude)
  • Lacks an instant release kit just like the FR920XT and the Fenix3

Phew – that’s the short version of what’s different at a feature-set level. But we’ve got factors like size. The FR735XT is smaller compared to the Fenix3 or FR920XT, and is more based on the size and weight of Garmin’s running-only watches. That’s very good news for all those wanting a smaller triathlon watch, but bad news in the event that you intend to mount it on your own bike. There’s no quick release kit that lots of triathletes use with other triathlon watches.

You’ll note above that it doesn’t have a barometric altimeter, instead by using a GPS based altimeter. This decision cascades right into a couple of downsides for the machine (which still costs $450USD). To begin with, it won’t count stairs within activity tracking mode – an attribute that a lot of $100-$150 activity trackers have the desired effect. Next, it appears to royally suck in terms of the GPS elevation charts I get. True, nearly all online platforms will re-write the elevation data anyway, but if you value that mid-activity, then this is obviously a consideration point. Finally, it lacks the ski/snowboard mode that other Garmin devices at the same price have – because again, it needs the barometric altimeter.

Ignoring my GPS based elevation quibbles though – the machine does otherwise work quite nicely. Garmin continues to boost their optical heartrate sensor (called ‘Garmin Elevate’), that they introduced last fall. While all past products have observed improvements via firmware aswell, it’s good to see these tweaks are making a notable difference – at least regarding running. For running, things do quite nicely for me almost all enough time. However while cycling it’s still kinda rough with regards to accuracy, especially outdoors (indoors is commonly fine). I found that whenever cycling on smoother roads at steadier intensities it’s good, but stop and go and rougher roads is still tricky. Other optical sensors from others still do better in this area (by a broad margin).

All of those other watch as a daily unit works accurately as you anticipate for a good watch. Alerts arrive instantly, and daily activity tracking also is effective. I’ve got no complaints in those areas. Battery life during GPS activities can be an area some are worried with, given the reduced 14hr battery. However, in my own testing I came across some methods for getting around that for all those pushing the limits of the battery convenience of a complete iron-distance race. But of course, it still won’t be for everybody.

Overall, I feel that if you’re looking at shorter distance triathlons (Sprint/Olympic/Half-Iron), the FR735XT may be the most capable unit in the tiniest package on the market. If you’re looking for something for iron-distance racing, then you’ll want to think about your projected finishing times.


Given that we’ve got our threesome taken care of, let’s make contact with solo sports, you start with running. Given the FR735XT is practically identical in external looks compared to that of the running-focused FR235, it stands to reason that as a running watch it handles pretty much from an application factor standpoint. However, unlike the FR235 it has a boatload more running features. Including the FR235 is a mid-range watch, whereas the FR735XT has lots of the higher-end running features. Functions such as a metronome for example, and Running Dynamics.

To begin with we’ll head outdoors and pick our sport. Here we’ll select running.

You now can either start the running session (or own it find satellites and HR), or you can dive into settings. We’ll do settings first. The FR735XT permits you to configure four data pages, each with up to four bits of information on them. Plus, you’ve got dedicated (optional) pages for: HR Zone Gauge, Map (breadcrumb), V