When fitness trackers and wearable tech exploded, swim trackers were treading water for quite some time. The innate need to waterproof the tech and offer complicated but valuable insight-like stroke detection and lap counting meant we’ve waited a while for fully-functioning swim trackers. Finally, wearables chronicling our aquatic endeavours are finally catching up to the kit we have for tracking our sporting pursuits on dry land.

There’s still a limited choice and, while plenty of fitness trackers will claim waterproof credentials, that doesn’t necessarily mean they’re capable swim trackers. Thankfully, there’s a growing selection of the best all-round fitness trackers, smart watches and sports watches that now offer strong suites of swim-tracking features.

The best among them offer features such as automatic stroke detection, accurate lap and distance tracking in the pool and GPS to chart open water swims. Some even offer fairly accurate heart rate monitoring in the water and post-workout insights to help you make sure you’re training smarter rather than harder.

Waterproof rating

Whereas smartphones tend to use the IP rating system to certify water resistance, most fitness trackers come with an ATM rating. ATM is short for Atmospheres, which indicates how much atmospheric pressure the device can withstand underwater. ATM 1 is the level of pressure in the atmosphere at sea level. An ATM five device rating means it’s can withstand the pressures at depths of up to 50 metres.

That makes them fine for swimming or snorkelling, but not for scuba diving. It’s important to consider that watches with this rating shouldn’t be used for high-speed water sports, or even diving off the high board at your local pool. The speed of hitting the water, combined with the change in pressure could break those all-important water seals.

Comfort and fit

Even if you’re doing a leisurely backstroke and not the vigorous butterfly, there are still a lot of forces at play when you’re forcing your arm through water. Therefore, it’s important you look for a device that offers a good fit that’s both secure and comfortable. Things to look out for here are soft straps, effective fastenings and a slim, sleek profile. If you’re using them for triathlon there’s also the ease of transition to consider and how well the trackers stays put in and out of the wetsuit.

How we tested

We gave all of our trackers a thorough workout in the pool, varying the drills, strokes and the intensity of our swim sessions to see what real-time training insights they offered. We also fired up their partner smartphone apps to find out how useful they were for post-workout information. We judged them here based on their tracking features, accuracy, comfort and convenience. All with a firm eye on price.  

Apple Watch Series 3 (GPS + Cellular): £379, John Lewis

Weight: 44g

Battery life: Up to 18 hours

Waterproof rating: 50 metres (5ATM)

Built-in heart rate: Yes

GPS: Yes

Apple’s smartwatch became a serious consideration for swimmers with the launch of the watchOS 4 software in late 2017. It can now automatically and accurately track distance, lengths, time and stroke type. It’ll even tot-up the distance for each stroke at the end of the swim. Helpfully, it’ll also count your sets and rest time so there’s no need to fiddle with a wet touchscreen to pause the swim when you take a little breather. The built-in GPS on this model also enables you to map your open water swims. For triathletes, Apple also caters for easy multi-sport transitions by hitting the + button within the Workout app.

While the Apple Workout app isn’t the most advanced swimming tool, it does offer detailed splits for 25m, 50m and 100m distances. During our testing we loved the ability to calibrate the pool length to the nearest metre, while Apple Watch owners also have the luxury of choosing third-party apps like MySwimPro for more detailed insights.

The Apple Watch will even track your heart rate during swims, but accuracy is understandably impacted in the water. If you buy the GPS + Cellular with built-in 4G connectivity model you’ll still be able to receive all of your calls and notifications while swimming, although we wouldn’t recommend a voice call during your breaststroke. Thankfully, there’s a handy screen lock mode to nullify any accidental screen activity.

Obviously swim tracking is only a tiny fraction of the overall Apple Watch experience, which is reflected in the price. If you don’t want those general iPhone calls and notifications delivered to your wrist on a daily basis, you should perhaps consider a dedicated fitness device.

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Moov Now: £57.93, Amazon

Weight: 6g

Battery life: 6 months

Waterproof rating: 30 metres (3ATM)

Built-in heart rate: No

GPS: Yes

At the other end of the pricing spectrum is the Moov Now; a dedicated fitness wristband packing in some serious swim-tracking tech. The small and lightweight device will automatically track your laps, time, distance, pace and stroke any time you take the plunge.

However, where the screen-less Moov Now really excels is the post-swim insight via the companion app. The ability to break down session data into lengths, so you can see exactly how many strokes you pulled and how you got from wall to wall, is really useful. You also see how long each lap took, as well as your turn time.

It provides feedback on your pool stamina, enabling you to monitor swim-fitness over time, while the post workout pro tips tell you what to work on during your next session. The app will also encourage you to build endurance by beating your continuous swim time, while offering an idea of whether those rests helped your endurance.

The Moov Now isn’t as resistant to water as others in this list, but can still handle the pressure in 30 metres of water, which should be plenty. The six-month battery life is a huge plus, but there’s no on-board heart-rate monitor (it can be paired with the Moov HR chest strap though).

The multi-sport tracker also offers similarly detailed insights for running/walking and cycling, so it’s great if you’re training for a triathlon. Boxing and circuit training are also supported.

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Samsung Gear Fit Pro2: £209, John Lewis

Weight: 34g

Battery life: Up to 4 days battery life

Waterproof rating: 50 metres (5ATM)

Built-in heart rate: Yes

GPS: Yes (also GLONASS)

One of the more attractive devices in our line-up is also Samsung’s best fitness tracker to date. The Gear Fit Pro2 has a curved, colour AMOLED screen, which is crisp, bright and extremely easy to read underwater. Natively, it can determine stroke type, while measuring lap time and distance, as well as the SWOLF (swim golf) metric. This awards you a score by combining your time and strokes per length, providing great insight into your swim efficiency.

The Gear Fit Pro2 has the excellent Speedo On app built-in, which gobbles up all of that lovely data for more detailed analysis and the chance to compete with other users in the community. For multi-sport athletes, Samsung has also included the popular MapMyRun, Endomondo, MyFitnessPal and UnderArmour Record apps.

Like the Apple Watch, the Fit Pro 2 also has a screen lock mode while you’re taking a dip. There’s 4GB of available storage, plus compatibility with Spotify’s offline mode (Premium subscribers) only. However, you’ll be hard pressed to find a set of headphones to wear in the pool to make the most of that.

It’s comfortable, lightweight and comes with a choice of straps. The only downside is the more expensive price point compared to its predecessor, but that additional swim-friendliness could make all the difference.

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Fitbit Ionic: £239.99, Fitbit

Weight: 45-47g depending on choice of straps

Battery life: Up to 10 hours in GPS mode

Waterproof rating: 50 metres (5ATM)

Built-in heart rate: Yes

GPS: Yes

Fitbit’s broadening from wristbands like the Charge HR, to fully functioning smartwatches has gathered steam with the Ionic. As with most of the trackers in our line-up it accurately tracks lengths, distance covered and the duration of your swim. However, it lacks features like automatic stroke detection, stroke count, pace per length and SWOLF score.

The Ionic runs Fitbit’s own operating system and app store, so you can access popular third-party apps like MySwimPro. This offers personalised swim workouts every day and the ability to customise the pool size. It also serves up a condensed dashboard, enabling you to check your progress on the bright (up to 1000 nits), 1.43-inch colour touchscreen while underwater.

As with the Apple Watch, the built-in heart rate sensor isn’t too reliable in the water, so an additional chest strap (you can find one here on our list of the best heart rate monitors) is required if you want beat-to-beat accuracy.

The Ionic is certainly a worthy fitness-based smartwatch (with 15 exercise modes), but it’s  swim-tracking features really cater more for the casual swimmer rather than serious swim training. Fitbit does say it is working to improve the native swim tracking features though so that may change. If you’d rather spend a little less, you can also opt for the newer Versa smartwatch (£199) or a simple wristband like the Flex 2 (£69.99). Both offer swim tracking.

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Garmin Forerunner 935: £426, Amazon

Weight: 49g

Battery life: Up to 24 hours in GPS mode

Waterproof rating: 50 metres (5ATM)

Built-in heart rate: Yes (but not during swimming)

GPS: Yes

The most serious piece of multi-sport tech on this list, and perhaps even on the shelves, the Garmin Forerunner 935 is a serious tool for very committed amateurs.

This multi-sport watch offers the most comprehensive set of swim-based features for triathletes. It automatically detects stroke type as well as lengths, distance, pace and stroke count and will also measure that SWOLF efficiency score we mentioned on the Samsung band.

It counts your laps and distance in the pool (push off the wall hard for more accurate counts!) and uses GPS to track your mileage and view your open water progress on a live map. The Drill Log mode also enables swimmers to record yardage earned in kick-sets and one-arm swims, or when using other techniques that aren’t covered by the four major strokes.

You can set up a specific swim profile that lets you customise the metrics you see on screen during your swim and there are also time and distance alerts, a handy countdown start and advanced rest timers. Everything is synced back to the comprehensive Garmin Connect app, which offers a wealth of insight into your workouts over time.

While it has a heart rate tracker, it doesn’t record data while swimming. That means you’ll need to pair the watch with the HRM-SWIM strap to unlock BPM-based training tools. The Forerunner 935’s work isn’t done once you leave the pool either. It’ll helpfully key you into insights on your training load and your recovery time.

The triathlon mode also makes it easy to switch between disciplines with a single button press, while also capturing those all-important transition times. Controls are button-based because there’s no touchscreen on this lightweight, compact device. We’d recommend this watch for the money-no-object athlete who values fitness features over the auxiliary smartwatch tools offered by the likes of Apple Watch and Fitbit Ionic.

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Polar V800+: £389, Polar

Weight: 79g

Battery life: Up to 13 hours in GPS mode

Waterproof rating: 30 metres (3ATM)

Built-in heart rate: Yes (but not during swimming)

GPS: Yes

Garmin doesn’t have the multi-sport market completely locked down. The Polar V800 is a direct answer to the Forerunner 935 and it’s significantly cheaper. Like it’s rival, it uses GPS and automatic tracking via a built-in accelerometer to support open water and pool swimming, It’s also adept at detecting your swimming style and rest times, while tracking the number of strokes, pace and distance.

The V800 also has a superb multi-sport training mode, so you can log your swim, bike and run in one training session while automatically encompassing transition time. The built-in HR sensor doesn’t work underwater, but like others here you can invest in a heart rate tracker like the Polar H10. There’s also a collection of smart tools like training load, recovery status, smarter calorie burn stats, a fitness test and an Orthostatic Test, which offers an indication of how your HR is responding to training, stress or illness.

You get limited support for smartphone notifications, enabling you to answer or decline calls, view messages and stay in touch with social media posts but this won’t necessarily satisfy if you’re looking for all-day smartphone features. On that note, the V800 isn’t the best looker on this list either, opting for sporty function over style.

The Polar only offers water resistance to depths of 30 metres (ATM 3), compared to 50 metres (ATM 5) on the Forerunner 935. The V800 has also been around since 2014, so it isn’t the newest kid on the block, while at 79g it’s also the heaviest watch in our list.

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The Verdict: Fitness trackers for swimming

Bang for buck you won’t find more swimming fitness insights for your money than you get with the Moov Now. If you can live without seeing your swim stats in real-time and you’re watching your budget, this is the smart option.

If you’re looking for a stylish smartwatch that you can wear all day but will also cover your casual laps of the local pool, the Apple Watch Series 3 is your best bet. If the price Apple Watch price tag is a bit steep and you want smartwatch on a budget then the Ionic is worth a look too.

However, if money is no object, and/or you’re pushing for a place the Ironman World Championships in Kona, then the Garmin Forerunner 935 is about the best multi-sport tool you can strap on your wrist.

IndyBest product reviews are unbiased, independent advice you can trust. On some occasions, we earn revenue if you click the links and buy the products, but we never allow this to bias our coverage. The reviews are compiled through a mix of expert opinion and real-world testing.