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Best smartwatch for iPhone 2021: Apple Watch, Wear OS, Tizen and more

Included in this guide:

The best smartwatch for iPhone including Apple Watch SE, Apple Watch 6 and Apple Watch 5
(Image credit: Apple)

While the absolute best smartwatch for iPhone might be an Apple Watch, that doesn't mean it's the only great option. Obviously, Apple's own wearables pair up brilliantly with iPhones, but there are still plenty of other good options if you want a watch to track your fitness while sending you relevant notifications, amongst other useful features. 

Generally, smartwatches that run Google's Wear OS work reasonably well with iPhones but you will miss out on a few features that only work when synced with an Android phone. However, Wear OS based smartwatches can look pretty stylish compared to Apple Watches so your decision may come down to why you want a smartwatch and if looks are important. As always, make sure to read our full reviews to be certain of the functionality you get here. 

It's also possible for iPhones and Samsung's range of Tizen-powered watches to work together too along with Fitbits and hybrid wearables from the likes of Withings. Simply put, if you have an iPhone, you're spoilt for choice here. The only recent entry you miss out on is the Samsung Galaxy Watch 4 otherwise the smartwatch world is your oyster. 

The Apple Watch 7 was launched on September 14 but you can't buy it just yet. It offers the smartwatch's first redesign with thinner bezels and a brighter Always On display too. While we're expecting it to shoot up the list soon, for now we have the still fairly recent Apple Watch SE coming in straight at number one. Well-priced and highly compatible with your iPhone, it's a great choice but there are plenty of other excellent options below too if the latest Apple Watch doesn't appeal.

What's the best smartwatch for iPhone?

Most smartwatches will track your basic health metrics such as steps and calories, while devices with built-in GPS make for perfect running, cycling and swimming companions. Many of the watches here also sync up so you'll receive notifications via your watch, saving you the need to dig out your phone as often.

We’ve fully worn, tested and evaluated all the watches in this list and ranked them based on software and which we think is best for most people. Bear in mind the watch at number one might not be best for you though depending on your needs, tastes and budget.

Best Apple Watch: what are the choices?

Apple Watch SE

(Image credit: Apple)

The best value Apple Watch at the moment

Specifications
OS: watchOS 7
Compatibility: iOS
Display: 1.78" OLED
Processor: Apple S5
Band sizes: Varies based on watch size
Onboard storage: 32GB
Battery: 18 hours
Charging method: Wireless
IP rating: Water-resistant to 50m
Connectivity: Wi-Fi, Bluetooth, NFC, LTE
Reasons to buy
+Smart design+Extensive features
Reasons to avoid
-No always-on display-Average battery life

The Apple Watch SE is the relatively recently released and affordable model of the Apple Watch. You really don't miss out on much by spending less. There's no always-on display which is a shame but other than that, it's mostly business as usual. 

Performance is speedy and far superior to the Apple Watch 4 and earlier. You still get extensive tracking features including heart rate monitoring, sleep tracking, and GPS, as well as the usual bevy of workout tools. It's mostly pretty accurate too although not quite on a par with dedicated fitness devices like the Garmin range. 

Still, as an attractive combination of good looks, good features, and a keen price, you can't go wrong with the Apple Watch SE.

Read the full Apple Watch SE review.

Apple Watch 6

(Image credit: Apple)

The best 'full' Apple Watch money can buy

Specifications
OS: watchOS 7
Compatibility: iOS
Display: 1.78" OLED
Processor: Apple S6
Band sizes: Varies based on watch size
Onboard storage: 32GB
Battery: 18 hours
Charging method: Wireless
IP rating: Water-resistant to 50m
Connectivity: Wi-Fi, Bluetooth, NFC, LTE
Reasons to buy
+Great color additions+Always-on display
Reasons to avoid
-Lacks a headline upgrade-Battery life needs to be longer

The Apple Watch 6 – alongside the Apple Watch SE – is Apple’s latest wearable until the Apple Watch 7 arrives. While the SE is relatively affordable, the Apple Watch 6 is the company’s top model, if you can stretch that far. 

While this isn’t a huge upgrade on the Apple Watch 5, it does have some handy new features and improvements, such as blood oxygen monitoring, improved battery life and screen, and an upgraded chipset.

It’s also available in some fetching new shades, and is the first Apple Watch to ship with sleep tracking – though this feature is now available on older models too.

It’s not perhaps the most exciting upgrade then, but it is one of the best smartwatch for iPhone, and one of the best smartwatches period.

Read the full Apple Watch 6 review

Apple Watch 5

(Image credit: Apple)

The second best Apple Watch money can buy

Specifications
OS: watchOS 7
Compatibility: iOS
Display: 1.78" OLED
Processor: Apple S5
Band sizes: Varies based on watch size
Onboard storage: 32GB
Battery: 1 day to 36 hours
Charging method: Wireless
IP rating: Water-resistant to 50m
Connectivity: Wi-Fi, Bluetooth, NFC, LTE
Reasons to buy
+Always-on display+More storage
Reasons to avoid
-Battery isn't incredible-Still pricey

The Apple Watch 5 is no longer the best Apple Watch, but it still comes close. Though while it’s now been superseded it's still not a cheap option.

The big upgrade here compared to previous models is an always-on display. This doesn't drain your battery life as much as you may expect as the watch will dim its screen to offer you notifications on your wrist at all times rather than you having to raise it and wake it up to see your stats.

And while it shipped with watchOS 6, it can now be updated to watchOS 7, so the software is brand new even if the hardware isn’t anymore.

If you own an Apple Watch 4, there's not much reason to upgrade here but if you own an older Apple Watch or you're looking to get your first smartwatch this may be a solid option for you providing you can still find one, that is.

Read the full Apple Watch 5 review

Apple Watch 4

(Image credit: Apple)

A still-solid Apple Watch

Specifications
OS: watchOS 7
Compatibility: iOS
Display: 1.78" OLED
Processor: Apple S4
Band sizes: Varies based on watch size
Onboard storage: 16GB
Battery: 1 to 2 days
Charging method: Wireless
IP rating: Water-resistant to 50m
Connectivity: Wi-Fi, Bluetooth, NFC, LTE
Reasons to buy
+Larger display+Lightweight design
Reasons to avoid
-Battery could be better-Doesn't offer always-on

The introduction of the Apple Watch 6 and 5 may have seen the Apple Watch 4 drop in terms of pure excitement, but it's now cheaper than ever and it's not all that dissimilar to the latest device.

This was the first smartwatch from the company to increase the display size to a 1.78-inch OLED. That looks great on your wrist, and the device comes in either 44mm or 40mm versions.

We particularly liked that the speaker is louder, plus the ECG monitor tech was a big upgrade at the time too. 

You won't get the benefits of an always-on display, but if you want to save a bit of money you may want to look at the Apple Watch 4 over the more recent additions to the range.

Read our full Apple Watch 4 review

smartwatch deals prices sales

(Image credit: Apple )

Now even cheaper, but still great

Specifications
OS: watchOS 7
Compatibility: iOS
Display: 1.65" OLED
Processor: Apple S3
Band sizes: Varies based on watch size
Onboard storage: 16GB
Battery: 1 to 2 days
Charging method: Wireless
IP rating: Water-resistant to 50m
Connectivity: Wi-Fi, Bluetooth, NFC, LTE
Reasons to buy
+Good battery life+Clear, bright screen
Reasons to avoid
-Only iPhone compatible-Siri still patchy

The Apple Watch 3 was once the best smartwatch to use with an iPhone... but it's not the best anymore. Even though you can now buy the Apple Watch 4, 5 and 6, this is still a fantastic smartwatch.

The Series 3 has a bright, high-quality screen, built-in GPS, waterproofing, optical heart rate monitoring and well over a day of battery life, plus all the things that make the Apple Watch 2 great, like a stylish design, water resistance and enough fitness features to cater to most users.

It’s a great all-rounder then, with style and substance, suited to both the office and the gym. There’s even an LTE model – though at a higher price. And of course, being an Apple Watch, it works perfectly with iPhone. Plus, this benefits from still being sold direct from Apple at the time of writing, while the Apple Watch 4 and 5 aren’t.

Read our full Apple Watch 3 review

Best Wear OS or Tizen watch

Wear OS and Tizen watches

You’re not just limited to the Apple Watch if you want a smartwatch for your iPhone. There are some great compatible options that run either Google’s Wear OS or Samsung’s Tizen software.

As you might expect, Tizen is only found on Samsung smartwatches (with the Samsung Galaxy Watch 4 using One UI Watch 3 and not compatible with the iPhone) but they are all excellent, offering attractive circular designs, top specs and good battery life.

Wear OS is used by several manufacturers including Fossil and TicWatch, two brands who tend to make the best of Google’s platform.

Samsung Galaxy Watch 3

(Image credit: Samsung)

The best smartwatch that isn't by Apple

Specifications
OS: Tizen OS
Compatibility: Android, iOS
Display: 1.2" or 1.4" 360 x 360 Super AMOLED
Processor: Dual-core 1.15GHz
Band sizes: 22mm or 20mm
Onboard storage: 8GB
Battery duration: 3 days on 45mm / less on 41mm
Charging method: Wireless
IP rating: IP68
Connectivity: Wi-Fi, Bluetooth, LTE (for extra)
Reasons to buy
+Great rotating bezel+Premium design
Reasons to avoid
-Battery life suffers-Bixby sucks

No longer the latest Galaxy Watch, the Samsung Galaxy Watch 3 remains the best non-Apple smartwatch as the Samsung Galaxy Watch 4 isn't compatible. If you don’t like the aesthetic of the Apple Watch and prefer a circular watch then this is the one to get.

The Galaxy Watch 3 comes in two sizes depending on your tastes and wrist size, with the smaller available in bronze or silver, and the larger in silver or black. Both are packed with fitness features like GPS, and top tier smartwatch functions.

You can also get a 4G model so you could still take calls and receive messages if you were out without your phone. 

But pairing any version of the Watch 3 with an iPhone means you’ll lose out on some of the functionality that you’d get paired with an Android device. 

Read the full Samsung Galaxy Watch 3 review

Fossil Sport

(Image credit: Fossil)

Fossil's latest big smartwatch attempt

Specifications
Compatibility: Android, iOS
Display: 1.2-inch 390 x 390 AMOLED
Processor: Quad-core 1.2GHz
Band sizes: 22mm straps
Onboard storage: 4GB
Battery duration: Two days
Charging method: Proprietary
IP rating: IP68
Connectivity: Wi-Fi, Bluetooth, GPS
Reasons to buy
+Lightweight design+Powerful watch
Reasons to avoid
-Lacks high-end features-GPS can be slow

Our favorite Wear OS watch right now is the Fossil Sport, which is cheaper than a lot of the watches you've read about above. 

It features the latest Qualcomm Snapdragon 3100 chipset that offers enough power to run any of the apps you'll find in Wear OS, and in our experience we found the whole interface to be notably smooth.

It'll last for around two days from a single charge, and the design here feels premium on the wrist when you consider how much it costs compared to other Wear OS watches.

There isn't much uniqueness to the Fossil Sport, but it's good at pretty much everything you'd expect a smartwatch to do and it'll work with your iPhone too.

Read the full Fossil Sport review

Samsung Galaxy Watch Active 2

(Image credit: Samsung)

Samsung’s sporty option

Specifications
OS: Tizen OS
Compatibility: Android, iOS
Display: 1.4" 360 x 360 Super AMOLED
Processor: Dual-core 1.15GHz
Band sizes: 20mm
Onboard storage: 4GB
Battery duration: Around 2 days
Charging method: Wireless
IP rating: 50m
Connectivity: Wi-Fi, Bluetooth
Reasons to buy
+Top performance +Two-day battery life
Reasons to avoid
-Quite expensive -Limited app choice 

The Samsung Galaxy Watch Active 2 is a fine Tizen smartwatch with great battery life and solid performance. 

Its circular display might attract you compared to the Apple Watch’s squarish look, and the Active 2 has a clever digital bezel to navigate menus. Its fitness features are just as good as Apple’s but you’ll have to use the Samsung Health app for iOS instead of Apple Health.

It’s waterproof and can track tons of different workouts including outdoor runs using GPS. There’s even a 4G option. Just bear in mind that while it works with an iPhone, it won’t be as smooth an experience as an Apple Watch. 

Read the Samsung Galaxy Watch Active 2 review 

TicWatch E2

(Image credit: Mobvoi)

A fully-loaded Wear OS watch you’ve never heard of

Specifications
OS: Wear OS
Compatibility: Android 4.3+, iOS 8+
Display: 1.39" 400 x 400 OLED
Processor: Snapdragon Wear 2100
Onboard storage: 4GB
Battery duration: Around 48h
Charging method: Magnetic connecting pin
IP rating: IP67
Connectivity: Wi-Fi, Bluetooth 4.1
Reasons to buy
+Affordable price+Easily two day battery life
Reasons to avoid
-No NFC for payments-Bland design

The TicWatch E2 is one of the more affordable devices on this list, and it's worth noting that this isn't the most premium looking device. That said, it's still a fantastic Wear OS watch.

It offers solid battery life as well as built-in GPS, an accurate heart rate sensor and sleep tracking as well.

The latest Wear OS software is running on the watch too, but you won't be able to get contactless payments as there's no NFC on this watch.

Read the full TicWatch E2 review

Other alternatives

There are quite a few devices you can use with your iPhone including some running Fitbit OS and others that you may not even refer directly to as a smartwatch. Read on about them all below:

Fitbit Versa 3

(Image credit: Fitbit)

The best smartwatch from Fitbit

Specifications
OS: Fitbit OS
Compatibility: Android, iOS
Display: 1.58" 336 x 3336 AMOLED
Processor: Dual-core 1.0GHz
Onboard storage: 4GB
Battery duration: Up to 6 days
Charging method: Proprietary charger
IP rating: 50M water resistant
Connectivity: Wi-Fi, Bluetooth
Reasons to buy
+Beautiful display+Built-in GPS
Reasons to avoid
-Poor design choices-Requires Fitbit Premium for full features

The latest attempt at a smartwatch from Fitbit, the Fitbit Versa 3 looks at the Fitbit Versa 2 and improves upon it. It finally has built-in GPS and there's still that gorgeous always-on display. The heart rate monitor is more accurate than before too making it a more attractive option for the exercise enthusiast. 

Fitbit OS remains not as fully fledged as the Wear OS or Apple Watch devices in this list as there are still a fairly limited amount of apps available to you, but if you want to have a watch as a fashion piece that also focuses on fitness, the Fitbit Versa 3 is still a good option. Alexa is on board along with Google Assistant, and a six day battery life is very appealing, although it does require you to switch off the always-on display.

Read the full Fitbit Versa 3 review.

Fitbit Ionic

(Image credit: Fitbit)

A noble first effort from the fitness kingpin

Specifications
OS: Fitbit OS
Compatibility: iOS / Android
Display: 1.45-inch LCD
Processor: Unknown
Band sizes: Small (its wrists 5.5" - 6.7" in circumference) and large (its wrists 6.7" - 8.1" in circumference) in box
Onboard storage: 7 days of movement
Battery: 4+ days (10 hours of GPS)
Charging method: Proprietary wired
IP rating: 50m water resistance
Connectivity: Bluetooth, Wi-Fi, NFC, GPS
Reasons to buy
+Solid battery life+Great fitness features
Reasons to avoid
-Controversial design-Lack of apps

Fitbit’s answer to the Apple Watch’s fitness threat piles all of its best fitness-tracking features into a highly functional smart timepiece. 

There’s GPS, continued heart rate tracking, excellent multi-day battery life and the ability to track multiple activities. 

That being said, the Fitbit Ionic runs off the bespoke Fitbit OS so it doesn’t offer the full fat smartwatch features of watchOS or Wear OS.

There’s also a shortage of apps available right now, you can download around 300 songs and connect Bluetooth headphones for phone-free exercise. Also, the design’s a bit controversial and very much has the look of a first-gen smartphone.

Read the full Fitbit Ionic review

Garmin Forerunner 735XT

(Image credit: Garmin)

For serious fitness fanatics only

Specifications
OS: Forerunner 735 software
Compatibility: iOS / Android
Display: 1.23-inch IPS
Processor: Unknown
Band sizes: QuickFit 22mm
Onboard storage: 80 hours activity data
Battery: 14 hours in GPS mode
Charging method: Proprietary wired
IP rating: 5ATM
Connectivity: Bluetooth, GPS
Reasons to buy
+Great looking+Advanced fitness and training features
Reasons to avoid
-Thick-ish bezel-No music storage

If you’re seeking a powerful fitness companion rather than a wearable extension of your smartphone, they don’t come much better than the Garmin Forerunner 735XT

The multi-sport GPS watch, designed with triathletes in mind, features an optical heart rate sensor and reams of deep data insights into your performance. 

Runners, for example, will glean metrics like ground contact time, balance, stride length, vertical ratio and much more. There’s a VO2 max estimator, race predictor and recovery adviser too.

Read the full Garmin Forerunner 735XT review

Withings Steel HR

Image Credit: Withings

A great hybrid choice

Specifications
OS: N/A
Compatibility: iOS / Android
Display: OLED monochrome 72 x 36
Processor: Unknown
Band sizes: Fits wrists up to 200 mm
Onboard storage: One week of data
Battery: 25 days
Charging method: Magnetic charging pad
IP rating: 5ATM (50m)
Connectivity: Bluetooth LE
Reasons to buy
+Best-in-class design+Reliable data
Reasons to avoid
-Expensive for functionality offered-No replaceable battery

This hybrid watch used to be called the Nokia Steel HR, but it has now been rebranded as the Withings Steel HR.

It features a built-in digital display that’ll show your heart rate in real time, as well as step progress and limited smartphone notifications. It has the neat analogue dial showing process towards a daily movement goal and can automatically track activities like running and swimming. 

There’s no GPS so you can’t expect hyper-accurate distance tracking, but the Steel HR is still a fantastic, stylish watch with great battery life that you can wear around the clock.

Read the full Withings Steel HR review

Looking for a smart running watch?

You should also check out our extensive range of devices to help you run - in our cunningly named best running watches round up - as many of these offer incredibly battery life as well as smart notifications from your wrist.

For instance, the Garmin Forerunner 935 will last almost 10 days on a single charge while running every day, allow you to take or reject calls and control your music - plus it's one of the most gifted exercise companions we've seen.

So if you're thinking of getting fitter - check out the burgeoning world of running devices to help you out.

James Peckham

James is Phones Editor for TechRadar, and he has covered smartphones for the best part of a decade bringing you news on all the big announcements from top manufacturers making mobile phones. James is often testing out and reviewing the latest and greatest mobile phones, smartwatches, tablets, virtual reality headsets, fitness trackers and more. He has also worked on other leading tech brands, such as T3 and Gizmodo UK, as well as appearing as an expert on TV and radio for the BBC and other publications. Be sure to follow him on Twitter for all the latest smartphone news.