Apple announced a new smartwatch at the beginning of September in the form of the Apple Watch Series 3, available in GPS only or GPS and Cellular models. The new smartwatch sits alongside the Apple Watch Series 1, which is essentially the same as the original device that hit shelves in April 2015, but with a newer dual-core processor than the first Watch.

The Series 2, which launched in September 2016, has been discontinued through Apple, though as you might still be able to get your hands on it elsewhere or want to know how the Series 3 differs to the Series 2 if you already have it, we've included it in this feature anyway.

With four generations having appeared since the Apple first set its sights on the smartwatch market, it's all a bit confusing to say the least. To make matters a little more simple, we've compared the Apple Watch Series 3 to the Series 2, Series 1 and the original Apple Watch (2015) so you can see exactly what the differences and similarities are, whether you're looking to upgrade or take the smartwatch plunge.

  • Original (2015) and Series 1: Splash proof, composite back, 450nits OLED Retina display, Ion-X glass for screen protection
  • Series 2 and Series 3 (GPS): Waterproof, composite back, 1000nits OLED Retina display, Ion-X glass for screen protection or sapphire on stainless steel and ceramic models 
  • Series 3 (GPS & Cellular): Waterproof, ceramic back, 1000nits OLED Retina display, Ion-X glass for screen protection on aluminium or sapphire on stainless steel and ceramic models 
  • Same rectangular design across all models, all straps compatible 

The original Apple Watch from 2015 features a rectangular solid body that sees the Digital Crown and separate button on the right, with a speaker and microphone on the left. The heart rate monitor is positioned on the underside of the watch body, along with the release buttons for switching out the straps and the OLED Retina display sits on top.

The Apple Watch Series 1, which replaces the original model, is exactly the same as the original in terms of design. Nothing changed. It is still splash resistant, it still features Ion-X glass on top of the display and it offers the same functionality as the first Apple Watch.

The Apple Watch Series 2 again offers the same design, meaning all straps are compatible. There are a couple of differences compared to the Series 1 and original though in that Apple waterproofed all the entry ports to make it swim-proof up to 50-meters, while the body is ever-so-slightly thicker for a bigger battery.

The Series 2 device also has a second-generation OLED Retina display that is two times brighter than the Series 1 and original at 1000nits, compared to 450nits. The Series 2 uses Ion-X glass to protect the screen on the aluminium case models, like the Series 1, but sapphire glass is present for the stainless steel and ceramic models.

The newest Apple Watch, the Series 3, also sticks with the same design and same strap mechanism as the Apple Watch models that have gone before it, though Apple has added a red accent to the Digital Crown of the GPS and Cellular model to differentiate it from not only the Series 3 GPS only model but the previous Apple Watch models too. Like the Series 2, the Series 3 models are all waterproof and they also all offer the second-generation OLED Retina display with Force Touch.

The Series 3 models with GPS only have Ion-X glass on top of their display and composite backs like the Series 1 models, while the Series 3 models with GPS and Cellular have Ion-X glass on the aluminium case models and Sapphire crystal on the stainless steel and ceramic case models, as well as ceramic backs.

  • Series 1: Standard Apple Watch model in aluminium with Sport Band
  • Series 3 (GPS only): Standard Apple Watch model or Nike+ model
  • Series 3 (GPS & Cellular): Standard model in aluminium or stainless steel, Nike+ model, Hermès model, Edition model
  • 38mm and 42mm size options 

When the original Apple Watch launched, its case was available in aluminium, stainless steel and special materials including solid gold, all of which came in two size options of 38mm and 42mm.

The original has long been discontinued with the Series 1 taking its place, but although the size options remain, this model only comes in the aluminium case option with a Sport Band. You can of course buy separate straps, but you won't be able to get the Series 1 in stainless steel or any other special material.

The Series 2 has also been discontinued with the Series 3 taking its place, as we mentioned above. The Series 3 comes in the same size options again, as well as in a choice of GPS only or GPS and Cellular. The GPS only model comes in a standard model with an aluminium case and a Sport Band, or a Nike+ model with an aluminium case and a Nike Sport Band.

The GPS and Cellular Series 3 model comes in five options. There is a standard model with an aluminium case and either a Sport Band or Sport Loop, a standard model with a stainless steel case and either a Sport Band or Milanese Loop strap, a Nike+ model with an aluminium case and either a Nike Sport Band or a Nike Sport Loop band, a Hermès model with a stainless steel case and Hermès leather strap along with a Sport Band included too, or a Watch Edition model with a ceramic case and a Sport Band.

  • Original (2015): S1 processor, HR, accelerometer, gyroscope, ambient light sensor, splashproof
  • Series 1: S1P processor, HR, accelerometer, gyroscope, ambient light sensor, 8GB capacity, splashproof
  • Series 2: S2 processor, HR, accelerometer, gyroscope, ambient light sensor, built-in GPS 8GB capacity, waterproof
  • Series 3 (GPS): S3 processor, W2 wireless chip, HR, accelerometer, gyroscope, barometric altimeter, ambient light sensor, built-in GPS, 8GB capacity, waterproof, Siri speaks
  • Series 3 (GPS & Cellular): S3 processor, W2 wireless chip, HR, accelerometer, gyroscope, barometric altimeter, ambient light sensor, built-in GPS, 16GB capacity, waterproof, LTE connectivity, Siri speaks

The Apple Watch Series 1 and original Apple Watch are identical in terms of hardware, except the processor. The Series 1 has an upgraded dual-core processor called the S1P, while the original model has the S1 processor.

Both models feature Bluetooth 4.2, 2.4Ghz Wi-Fi 802.11/b/g/n, a heart rate sensor as we mentioned, accelerometer and a gyroscope. They also both have an ambient light sensor and they are splash resistant but not waterproof, as we mentioned. A built-in lithium-ion battery is under the hood of both with a life of up to 18 hours, while storage capacity of the Series one is 8GB.

The Apple Watch Series 2 offers the same hardware as the Series 1 when it comes to Bluetooth, Wi-Fi, the various sensors and storage. The battery is said to be larger by roughly 30 per cent though.

It also adds a different dual-core processor called the S2. This chip allows for built-in GPS, which combined with the waterproofing and the brighter display make for some significant differences between Series 2 and Series 1.

The Series 3 improves on the hardware front again. It features all the same specifications as the Series 2 but it adds a barometric altimeter, along with a new faster again dual-core processor called the S3, as well as a Apple wireless chip called the W2. Both the GPS and GPS and Cellular models offer Siri directly from the watch rather than transferring it to your iPhone.

The GPS only model has 8GB of storage like the Series 1 and Series 2, while the GPS and Cellular model has 16GB of storage, while also offering LTE connectivity, meaning you can make and receive calls and text messages as well as perform all the tasks you'd want to without your iPhone in range.

  • All will run WatchOS 4 from 19 September
  • Same user experience
  • Extra features on Series 3

The Apple Watch Series 3 arrives on WatchOS 4, which the Series 2, Series 1 and the original device will see an update to from 19 September.

There have been several new features added to the new software including enhancements to heart rate monitoring, with both resting heart rate and recovery heart rate tracking coming into play, a new high intensity section within the workout app, enhanced swim tracking (Series 2 and 3 only), improvements in music and a Siri watch face.

The Series 3, Series 2, Series 1 and original Apple Watch will all therefore offer almost identical user experience but thanks to the added hardware features of the Series 3, the newer device will have a few extras here and there, especially in the case of the LTE model.

  • Apple Watch (2015): Discontinued
  • Series 1: From £249
  • Series 2: Discontinued
  • Series 3 (GPS): From £329
  • Series 3 (GPS & Cellular): From £399 

The original Apple Watch and Apple Series 2 are no longer available to buy, though you might find them on sites like Amazon.

The Apple Watch Series 1 is the cheapest way to get your hands on Apple's smartwatch through Apple itself, with a starting price of £249.

The Apple Watch Series 3 with GPS only starts at £329 for both the standard model and the Nike+ model. The Apple Watch Series 3 with GPS and Cellular starts at £399 for the standard model or Nike+ model, £1199 for the Hermès model and £1299 for the ceramic Watch Edition model.

The Apple Watch Series 1 is available to buy now, while the Series 3 models will open for pre-order on 15 September and hit stores on 22 September.

The difference between the original Apple Watch and Series 1 is literally just the processor, meaning upgrading from the original to the Series 1 would probably not be worth it.

If you didn't invest in the original and you've decided the Apple Watch is now something you want, buying the Series 1 over the new Series 3 model will save you at least £120, but you miss out on some key features.

The Apple Watch Series 3 not only adds a new processor again, but it offers a much brighter display, built-in GPS, a barometric altimeter, bigger battery and that all important waterproofing, as well as the potential of LTE connectivity if you've got the budget for an extra £150.

All the other features might remain the same, including design, but for some, the built-in GPS, waterproofing and LTE connectivity could be the three features you needed to take the smartwatch plunge. For others, the Series 1 will more than suffice.