Garmin Forerunner 945 vs Polar Vantage V: Top running watches compared

In the world of multisport watches, they don’t come much better than the Garmin Forerunner 945 and the Polar Vantage V.

These two high-end training tools boast some of the most advanced hardware and software to help athletes-in-the-making reach their potential. While the Fenix 6 is now the king of the Garmin sports watches the Vantage V is still the biggest, baddest Polar sports watch – at least until we review the new Polar Grit X.

Read our full testing: Polar Vantage V review | Garmin Forerunner 945 review

But how do you know which is the best watch for you?

From design to battery life, sports tracking to smartwatch skills, we’ve spent two months testing these class-topping trackers side-by-side to help you choose. Here's our take.

Forerunner 945 and Vantage V: Specs compared

Garmin Forerunner 945 vs Polar Vantage V: Design

There are lots of similarities between the watches. They’re almost the same size, have almost identical screen size and resolution, and sport five physical buttons for controls. Even the strap width and the number of strap holes are exactly the same, so there’s virtually nothing between them in terms of sizing and fit.

However, they still look very different. With its stainless steel case, thin bezel and metallic-ridged buttons, the Vantage V has a more modern, minimal style. The Forerunner 945 adheres to Garmin’s familiar sports watch design with a fibre-reinforced plastic frame.

The Garmin is slightly larger than the Polar – 47 x 47 x 13.7 mm compared to 46 x 46 x 13 mm – but the use of plastic over metal means it still comes in lighter – 50g compared to the Polar’s 66g. The weight difference doesn’t impact comfort when you’re working out but it does mean the Forerunner 945 feels and looks a little less premium.

When it comes to comfort, there’s not a huge deal to choose between the two. The Garmin strap is made from a slightly softer and smoother silicone and the shoulders of the Vantage V are rigid compared to the Forerunner’s more standard design. The Vantage can feel a touch less flexible but it’s slight.

The Vantage V’s optical heart rate sensor bump also protrudes much more than the Forerunner 945 so the Vantage sits a little higher off the wrist but there’s a strong argument that the bigger the bump, the better the optical sensor contact.

When we wore each watch for long periods of time, we experienced some rubbing and discomfort from both. It’s easily mitigated by tightening and loosening them before and after working out but if you forget to loosen you’ll feel it after a while.

Both watches feature five side buttons for control but the Vantage V also has a touchscreen for the best of both worlds. Though we found it was much easier to default to using the buttons.

The Garmin buttons are a little more responsive, requiring less of a firm press than the Polar but the Vantage’s longer, ridged buttons are a bit easier to find.

As you’d expect, both watches are waterproof and allow for swimming up to 50 metres.

Garmin Forerunner 945 vs Polar Vantage V: Screen

There’s one clear winner here. The transflective colour display on the Forerunner 945 is considerably brighter, sharper, clearer and easier to read in all lights.

By comparison, the Vantage V suffers a little from reflective glare. It’s still vibrant and perfectly legible, it’s just not as punchy and you have to use the battery-affecting backlight more than you do with the Forerunner.

Aside from that Vantage V touchscreen, the other major difference here is that the Garmin is far more customisable.

You can choose from a range of watch faces each prioritising different data for the homescreen. Plus you can also choose from up to 18 widgets to scroll through, dictating your quick view and shortcuts to everything from weather to Spotify controls. The Polar’s six screens are all fixed.

Garmin Forerunner 945 vs Polar Vantage V: Battery life

These two watches offer some of the best battery life performances we’ve seen. The official numbers give the Vantage V the edge by four hours in GPS/heart rate training mode, however, in smartwatch mode the Garmin boasts almost double the lifespan, 14 days compared to the Vantage’s seven.

In our real world tests both watches lasted just short of a full week. That included four hour-long runs, one 2-hour run and general usage with continuous heart rate on but smart notifications switched off.

The Polar needed charging first – about half a day before the Garmin – but neither had enough juice to get us through our next workout so in practical terms, as a sports tracking tool, it made little difference.

However, if you’re considering longer endurance events such as ultras or Ironman, the Forerunner 945 has the edge over the Vantage V thanks to UltraTrac mode – where you sacrifice a bit of GPS accuracy for longer battery life up to 60 hours.

When it comes to charging up both watches took the same amount of time to fully juice up and both brands have started to make their proprietary charging cables consistent across their product ranges.

Garmin Forerunner 945 vs Polar Vantage V: Heart rate

Despite improvements to wrist-based heart rate tech in recent years, there’s still no true replacement for chest strap accuracy. So it’s important to point out that both watches happily pair with Bluetooth heart rate accessories. In fact, to make the most of the Vantage V’s full suite of recovery insights it’s essential to get a chest strap.

When it comes to optical heart rate both devices carry their maker’s most advanced optical heart rate sensor tech. The Polar Vantage V features Precision Prime with two LED colours and skin contact sensors that can weed out disturbances to the heart rate signal. The Forerunner 945 has Garmin’s own flagship Elevate heart rate tracker.

We tested them head to head on a number of runs and in the pool. Here’s what we found:

Wrist-based heart rate while racing a half marathon

As you can see from the table and the graph, the topline results clocked during half marathon race were almost identical. However, there’s quite a significant discrepancy in the heart rate zone data.

Both watches rightly clocked us running in the top two intensity zones but the Garmin has a larger portion of the race in Zone 4. That’s despite the fact we amended our heart rate zones to ensure they matched.

On closer inspection, we noticed that for this session – and for reasons we can’t fathom – the Forerunner 945 inexplicably changed the heart rate zones, sending those readings out of whack.

Wrist-based heart rate while pool swimming

In the pool we put in a 1,100m swim broken down into a main block of steady intensity laps, followed by some sprint intervals. Here, the Forerunner 945 appears to have outperformed the Vantage V.

Despite keeping a steady pace and intensity for the main block of the swim, the Polar registers an early spike and then reports quite a few sudden drops towards resting heart rate at points where we weren’t resting for long enough to allow our BPM to fall.

These drops would also account for why the Forerunner 945 tracks more time in Zone 3 and 4 while the Vantage V has us spending more time in Zone 2 and 3.

From the structure of the swim session, Garmin’s data feels more accurate.

Garmin Forerunner 945 vs Polar Vantage V: Apps, syncing & connectivity

If you’re investing more than in watch, chances are you’ll want to dig in and analyse your training data. That means firing up the app and web tools.

Polar Flow and Garmin Connect have improved greatly but a bit like iOS against Android, PC versus Mac, they still divide opinion. There are fans and haters of both.

The insights and tools on offer are too extensive to do a detailed comparison here but both provide detailed post-workout summaries, fitness progress charts, training load reports, activity and sleep reports, goal-based training plans, community features and challenges. However there are some crucial differences to take into account.

Unlike the Forerunner 945, the Vantage V doesn’t automatically sync your post-run stats to the Polar Flow app. You have to open the app, hit a button on your watch and stir the tanks manually. That’s a bit annoying.

By contrast, once you’ve set you Forerunner up with Bluetooth to your phone and/or a WiFi network it’ll sync as soon as you’re in range. No mess, no fuss. It’s a small thing but it makes a difference.

We also found that the Polar failed to sync more times than the Forerunner 945 which added to the minor frustrations.

The Garmin Connect app is also much more customisable, slightly more intuitive to navigate and overall has more depth of data. However, when it comes to the web interface, Polar Flow is more of a match. So it’s worth considering if you’re happy perusing your stats on a desktop or you prefer everything on your smartphone.

In terms of monitoring training effect, training load and your progress through a training block, Polar Flow presents much more detailed and clearer charts. The Cardio Load reports, in particular are far more useful and digestible than Garmin’s Training Status reports. So if you’re really looking to monitor the impact of training over time, Polar’s tools are currently better.

Garmin Forerunner 945 vs Polar Vantage V: GPS

The Garmin Forerunner packs GPS, GLONASS and Galileo while the Vantage V has GPS and GLONASS. So in theory the 945 will be better at hooking up and tracking across a greater portion of the planet.

If your runs take you into the wilds a lot that’s good news. However, in London we found the Vantage V always got a GPS fix at least 15 seconds ahead of the Forerunner 945.

In terms of accuracy, on average across our comparison test runs, the Forerunner tended to register slightly longer distances. For example, during the very twisty, suburban Ealing Half Marathon, the Vantage V clocked the distance at 13.05 miles compared to the Garmin’s 13.25. Both are wrong and it’s not a huge discrepancy but as you can see from the map, the 945 had us running through school buildings.

During the New Forest Marathon woodland run, we tested the Forerunner’s UltraTrac against the Vantage V’s standard GPS and the former performed very badly.

The 945 clocked 31 miles on a marked marathon distance. Even if you’re running an ultra where you expect the GPS distances to be out and accuracy is less of a concern, a 6 mile misread is a lot.

The Polar’s biggest GPS problem real-time pace. Throughout our tests we watched it jumping all over the place, from 9 minute miles down to 5:30 minute miles and back again, despite the fact that we hadn’t changed stride. It made it very difficult to use as a real-time race-pacing tool and during runs where fine-tuned targeted pacing mattered we found the Garmin much more steady, consistent and reliable.

Garmin Forerunner 945 vs Polar Vantage V: Swimming

In the pool the watches perform equally well, automatically tracking laps, pool length and overall distance, though both occasionally clocked the odd extra lap or two.

In terms of swim stats you get similar insights. There’s pace along with stroke counts for average stroke rate and average number of strokes per minute and per lap. You also get SWOLF swimming efficiency scoring, however, the Polar is the only one that automatically tracks your stroke type and breaks the distance down accordingly.

The Forerunner 945 also has a feature that lets you track training drills separately.

Garmin Forerunner 945 vs Polar Vantage V: Sleep tracking

The importance of good sleep for optimal training and recovery has become a huge talking point and when it comes to sleep tracking, once Polar rolls out the Nightly Recharge features from the Ignite to the Vantage V, it’ll be a long way ahead of the Garmin Forerunner 945.

For a start the latter doesn’t currently show your sleep data on the watch, you have to dive into the app for that. And while the Forerunner 945 offers a sleep stage breakdown for REM, Deep, Light and Awake and Pulse Oximetry to monitor your breathing, the way the information isn’t nearly as detailed or useful as the stats you get from the Vantage V.

The Vantage V gives you a handy sleep continuity reading, an overall sleep score and also lets you record your own subjective feedback on how well you slept. With the Nightly Recharge firmware updates you’ll also get an overall reading that combines your sleep score with how well your Autonomic Nervous System recovered overnight, so you can get a quantified sense of how ready you are to train.

There is a caveat here though. Without accuracy these features rapidly become meaningless and at times, both watches struggled to recognise some basics.

For example, the Garmin regularly decided we were asleep when we were in fact chilling on the sofa. It also failed to spot when we’d woken up but stayed in bed awake. As a result it regularly vastly overestimated total sleep time.

The watches also failed to spot occasional long periods of waking interruption during the night. But overall the Vantage’s sleep tracking was far more accurate and generally more useful and that’ll only become more pronounced with the planned updates.

Garmin Forerunner 945 vs Polar Vantage V: Training and recovery insights

The ability to use data gathered during and after workouts to make smart decisions about training schedules, is fast becoming one of the biggest selling points for multisport watches.

We recently put these training effect features to the test and you can read our findings on the accuracy and validity of them here. But in terms of the insights on offer and how they’re delivered, here’s how they stack up.

Power: The Vantage V was the first and remains the only watch to offer running power tracking native from the wrist without an accessory. It’s a great tool for bringing consistency to training sessions and as a pacing tool come race day. If you want to use running power on the Forerunner 945 you’ll need to cough up extra.

Training Load/Training Status: The Vantage V makes the most of the fact it tracks running power from the wrist to tracks your cardio and musculoskeletal training load. Whereas the Garmin’s readouts are based on heart rate alone. Both devices will tell you how your cumulative training volume is impacting your fitness, for example, maintaining, productive, detraining, overreaching.

On the watch, the Forerunner 945 gives you a slightly more detailed assessment of how your overall load is spread between Anaerobic, Aerobic High and Aerobic Low training.

Recovery: You get recovery recommendations from both devices based on heart rate. Garmin provides a time-based recommendation and a short tip such as ‘Easy Effort Recommended’ while Polar will tell you if your system is fully recovered and also make a training recommendation for that moment in time, e.g. Train Light or Rest.

In order to access the Vantage V’s full recovery advice you need to take a daily orthostatic test with chest strap. That’s an extra commitment but most experts point to the fact that the crucial heart rate variability (HRV) tests can only be done accurately with a chest strap.

The language Polar uses in this feature set is slightly more human than Garmin. You get recommendations expressed as advice whereas the Forerunner still has a tendency to leave you to interpret complicated looking numbers.

Fitness progress can be charted with a VO2 Max reading on both devices.

Verdict

Having worn these watches for two months, we’re happy to say that both are very strong. And whichever watch you plump for, you’re unlikely to be disappointed.

In a straight out head to head based on the sports tracking, training and recovery features, there’s very little to choose between them. Polar’s training tools and advice is probably a little more human and charting training load trends is more straightforward. But the watch you choose is more likely to be decided by a few other key factors.

If you’re looking for a device that tracks running power without a footpod or accessory the Vantage V is your best best bet.

If smartwatch smarts like music, contactless payments and customisation are important to you then the Forerunner 945 is definitely the watch you want. Polar are some way behind on this.

For those interested in ultras, the Garmin’s UltraTrac mode and extendable battery life is an important distinguishing feature.

If budget is a major concern, then the Vantage V’s £80 cheaper price tag gives you more bang for buck.