As an Ironman coach who coaches a number of beginners, one of the first questions I get asked is – what sort of training watch should I get?
My answer is always – “I haven’t done a lot of research on other watches for endurance events, but one thing I do know is that the Garmin Fenix 5 is the best watch I’ve even owned!”.
I first purchased the Fenix 5 about a month prior to Ironman Cairns in 2017. I’d done a few long rides (i.e. 6+ hours) and when I got home, my Garmin 920 had less than 50% power. Even though I was aiming for a sub-10 hour Ironman, I thought this was cutting it too fine – imagine approaching the end of the Ironman and your watch runs out of battery – how would that look on Strava?! I needed a new watch!
At the time, the Garmin Forerunner 935 and Garmin Fenix 5 had recently been released to mostly positive reviews, and further research with early users seemed to back up the reviews. The 935 and Fenix 5 have the same hardware and software (except the 935 has Wifi whereas the base model Fenix 5 does not), so it was a toss up. I decided on the Fenix 5 as I really liked the idea of a watch that looked good at work, as well as functioned well in training and races.
In summary, here are the important things (to me) that I got with the Fenix 5:
• Battery life that lasted at least 20 hours with GPS running continuously and over a week in general
• Huge number of workout modes including triathlon, pool swim (automatically counts laps), indoor cycle, treadmill running, hiking, walking, etc.
• Optical wrist-based HR with ability to use external HR strap (despite some reports I’d read that the wrist-based HR wasn’t accurate, I’ve found it to be pretty good)
• Ability to measure heart rate variability (when used with external HR strap). This is an emerging training metric to measure chronic training fatigue.
• Excellent GPS tracking. Highly accurate with GPS and GLONASS (Russia's version of GPS)
• Great interface and transfer with Garmin Connect mobile app and then to TrainingPeaks, Strava etc. Syncs automatically right after the workout.
• Timer/stopwatch and ability to create shortcuts (it’s amazing how often I use a simple timer!)
• Ability to customize the watch face (e.g. digital face for training, analogue face for work!)
• Real buttons, NOT touchscreen. I find touchscreens too fiddly in training and racing and they do funny things when sweat or electrolytes hit them (ever tried using your iphone when you’re sweaty?) – I want real buttons!
• Highly durable metal and fiber-reinforced polymer case and scratch resistant glass (there’s hardly a scratch or dent after 2 years!)
• Ability to easily install some great widgets (a.k.a. apps), such as world time zones (good for traveling to an event or coaching athletes around the world!), sunrise/sunset times (great for scheduling training), Uber ETA (great when you hurt your knee and need a lift home!), and many many more!
• Relatively light – not something I notice on my wrist when running or swimming. (The Garmin Forerunner 935 version is even lighter)
My Fenix 5 has now been with me through four Ironman campaigns including two Ironman World Championships – it’s never let me down and has got a lot more life left in it. I couldn’t rate the Garmin Fenix 5 (or Forerunner 935) more highly for triathlon training. It ticks all the boxes.
P.S. The new Garmin Forerunner 945 looks just as good as the 935, yet has the ability to store music, so check that out too.

Photo: The Garmin Forerunner 920 (shown above racing in China) was a good watch, but the battery life was not long enough for Ironman