​Suunto 3 Fitness review

The Suunto 3 Fitness is a sports watch clearly aimed at casual fitness fans. The kind that don't want to spend big on a Spartan or a pricey Garmin or Polar, but still want something that goes beyond what a fitness tracker can serve up.

This sub- watch packs in serious sports tracking from Suunto's more expensive range, but also showcases the company's new adaptive training plans and guidance features that aim to take the thinking out of staying fit, building training plans that adapt depending on the time you have to spare.

Along with a focus on building more personalised training plans, the 3 Fitness also doubles as a fitness tracker, including sleep monitoring that feeds into new stress and recovery features. With heart rate data central to getting the most out of the watch's main features, there's an optical sensor powered by Valencell who has put its sensors into a host of high profile wearables and hearables.

On paper, this is an affordable sports watch that has a lot going for it and attempts to do something new to make training feel less daunting. But does it achieve its goal? We've been getting to know the Suunto 3 Fitness for a few weeks now to find out. Here's our comprehensive verdict.

Suunto 3 Fitness: Design and comfort

While Suunto has done its best to keep its pricier Spartan watches slim, they remain bulky beasts, Spartan Trainer Wrist HR aside. This though is a watch made to be worn day and night so it's good to see that Suunto has managed to shrink down the frame to make that possible.

The 43mm watch weighs just 36g and comes packing interchangeable 20mm silicone watch bands so it's super light, far less imposing than Suunto's Spartan watches and crucially, it's comfortable to wear. The 30m water resistance increases its ability to be worn 24/7, letting you go for swim with it, but if you were hoping for something that looks anything other than sporty, you're sadly out of luck.

We had the black glass fibre reinforced polyamide (essentially plastic) version with the stainless steel bezel and black silicon strap, which emphasises just how the big black screen bezel is winning the war for space on the small, 218 x 218 resolution display. You do have your pick of pink and ocean blue options, while a gold and another black option pushes the price up slightly. Thankfully though, it still manages to stay below the price mark.

Speaking of the screen, it's pretty low on the resolution side of things. Even next to a similarly priced with a Garmin watch with a monochrome display, it's still not the sharpest or the crispest, with colours very muted. Visibility is good but not great and there's a backlight to aid those nighttime training sessions. There's no touchscreen support here so five physical buttons are your means of navigating and selecting things on the watch. It's a pretty standard setup, but it definitely pays to spend a bit of time getting to know what does what before you start tracking. There are a lot of sub screens to discover that you might miss on first inspection. Around the back is where you'll find an optical heart rate monitor and that's your lot.

It's not the prettiest sports watch, but its small, light, and you can wear it all day and night with ease.

Suunto 3 Fitness: Sports tracking and adaptive training

Despite its slender frame, Suunto manages to cram in an impressive amount into that small body. For starters, you have multiple sports tracking modes, which includes running, swimming (pool and open water), cycling, a multi sport mode designed for triathletes and a standard sport mode for everything else you want to track. This is a good point to mention that while you can track multiple sports, there is no built-in GPS. Yes, you heard us right. Tracking is done via accelerometer-based motion sensors and if you want that GPS hit, you'll need to piggyback off your phone to do so. Not really ideal.

Read this: Understanding your running watch stats

The watch will prompt you do that for compatible tracking modes, and tapping into the Connected GPS mode on the first few sessions is said to improve the reliability and accuracy of tracking on the watch when it's not available. Without connected GPS, we did find tracking to be more than a little off in running mode so it pays to spend some initial time making use of the connected GPS mode to get things better calibrated.

10k race test: Suunto 3 Fitness (no GPS) and Garmin Forerunner 935 (GPS)

That being said, the sports tracking experience in general is a very good one. For running, you're getting the very basics in terms of metrics with a big emphasis on displaying real-time heart rate data. The pared back data makes it easy to absorb during a run and you'll get a vibrating buzz and a pinging sound to tell you when you've notched up another km or mile. It's a similar story with swimming, which we found to be as accurate as the Garmin Forerunner 935 we put it up against – and it matches pricier Suuntos for performance in the pool. The general sports tracking mode strips back the metrics further, but again, it's not that much different from what you'd get from similar features on Garmin, Polar or Fitbit watches.

The big deal here though is what Suunto calls adaptive training guidance. This is essentially Suunto's way of building training plans based on your fitness level (from estimated VO2 Max scores), any recorded training and profile (age, weight, height etc). It'll then take this all into consideration and build a seven-day training plan to keep you on top of your fitness levels. If you miss a session, the plan adapts to compensate for that. Just to be clear, there's no going into the Suunto app and setting a target or saying you want to train for a 5K here. It's all about maintaining fitness based on the data you put into the watch.

How that presents itself on the 3 Fitness is a series of data screens on the watch that display your training plan by day, your weekly training average and the individual sessions. So this can range from an Easy 40 minutes or a Hard 40 minutes. That intensity is measured by heart rate and during those sessions will make sure you are hitting those intensity targets. When you head to the Exercise tracking screen, it'll tell you whether it's a rest day or it's time to get some proper training in, to save you scrolling through the training plan data screens.

Before you get that plan started though, you need to let the watch know your current fitness level, which involves running or walking for at least 15 minutes with connected GPS (paired to your phone) or calibrated speed and distance. That's something that's not immediately clear from the outset, and arguably a key part of ensuring these training plans are really useful. With such a big emphasis on heart rate zones for these training sessions, it's key that you know your breakdown. We can help you out with identifying those heart rate zones.

In essence, what you get is a promising concept. The plans are really easy to follow and the visual and audio prompts to push you to stay in those zones work nicely. It's nice to be able to see your plan on the watch instead of referring to the companion app too. But we can't help thinking that not having the ability to set your own targets or to want to train for a race is a missed opportunity. It's something that works well with Polar's Running Program, which also includes an adaptive element to training. Granted, Suunto's approach is not just about running but for general fitness levels, but it would be nice to at least have the option to make those training plans more focused.

Suunto 3 Fitness: HR accuracy

With heart rate monitoring so integral to how effective the 3 Fitness is at keeping you fit, it of course needs to be accurate. Thankfully, since Suunto introduced optical heart rate monitors to its watches, it's been one of the company's standout features and is up there with the TomTom and the Polar M430 for the most reliable wrist-based heart rate monitors we've tried on a sports watch.

Essential reading: How to use your running watch for interval training

So we were hoping for more of the same and, by and large, it delivers a good but not stellar performance. Resting heart rate data was in line with the Forerunner 935 and Polar H10 chest strap we measured it against, and for a gentle, well paced run, it delivers reliable results as well. It's the high intensity test where wrist-worn HR monitors usually fall short. With things like fit, skin tone and generally the increased number of factors that can impact on a reliable and accurate reading, it's high intensity training where it really shows.

HR accuracy test: Suunto 3 Fitness (left and centre) and Polar H10 (right)

When we put it up against the Scosche Rhythm24 heart rate monitor and Polar H10 for some interval running, everything felt generally fine during the run. Like many wrist-based optical heart rate sensors, it does tend to take a little longer to drop down to the resting heart rate, which means that during rests in between the intervals it could at times display 4-5 BPM higher readings. Maximum readings however at times read as much as 8-10BPM above the heart rate monitors we tested it against. Those differences could push you into a different heart rate zone, which then does impact on the whole concept of heart rate based training. The fact you can pair it with Suunto's heart rate monitor chest strap is definitely a big plus here though.

Suunto 3 Fitness: Activity tracking and smartwatch features

This sports watch also doubles as a fitness tracker, letting you track steps and see estimated daily calories and active calories (calories you want to burn), plus it even features rings – a bit like the Apple Watch – to indicate progress towards your activity tracking goals for the day.

It also offers sleep tracking, monitoring duration and quality, which feeds into Suunto's onboard recovery and resources features. This factors in stress (measured through heart rate variability and daily heart rate readings) as well as sleep and physical activity to indicate whether you are in good shape to get in a strong swim or maybe you should save yourself for tomorrow. The resources screen on the watch lives alongside the stress and recovery screens, displaying your body's resources from the last 16 hours to help you pick the optimal time to go work out.

As a fitness tracker replacement it does a solid job, and it's come on leaps and bounds from the fitness tracking features included in Suunto's Spartan range. It's no Fitbit, but it certainly offers a good balance of data as well as useful insights that can actually be of value to your training.

If you were expecting or at least hoping for the Suunto 3 Fitness to replace your smartwatch, though, you might be left disappointed. Aside from notifications, which do at least work with third-party apps, that's your lot. There's no music playback control here or the ability to act on notifications. There's nothing in the way of adding apps or extra features aside from Suunto's firmware updates.

Suunto 3 Fitness: Suunto App

This Suunto watch is unique in the sense that it doesn't work with the same MovesCount app that other Suunto watches work with. Instead, you'll need to download a new app that's simply called Suunto.

What you'll find here is a more feature packed version than MovesCount that can suffer from the odd syncing issue here and there. The new app itself looks great, putting daily activity front and centre a lot like the Garmin Connect app does. Below that is a stream of tracked sessions from your Suunto pals, while your user profile displays your entire workout history. There's also a Diary tab breaking down training, step, calorie and sleep data while the Explore feature lets you, well, explore your surroundings and build routes. Although with the latter, syncing routes to the watch is not possible yet.

It remains a pretty streamlined app and all of your data is well presented, especially when you drill further into sessions. One thing we did notice however is that there appears to be no way to share data to other services, which we hope gets added if Suunto intends to launch more devices that work with the new app.

Suunto 3 Fitness: Battery life

Battery life on the Suunto 3 Fitness entirely depends on which features you make most use of. If you're all about 24/7 activity tracking, then it should keep going for up to five days comfortably. When you factor in Connected GPS – also known as using your phone's GPS – it should be good for 30 hours, or 40 hours in training mode when you're not tapping into GPS.

Based on our experience using all of those features with 2-3 training sessions thrown into the mix, plus sleep tracking, you could probably could stretch to an entire week before it needs charging. For the kind of person that we imagine this is aimed at, and we are talking someone that's not training for a marathon, that's a decent showing.

Amazon PA: Suunto 3 Fitness

When it does run out of battery, the good news is that it's a zippy little charger and can get back up to 100% in just over an hour. The bad news is that it has one of those clothes peg-style charging cables that we are not the biggest fans of, so you need to ensure you wait for that buzzing sound to check it's been clipped properly in place.