iPhone Duo review – a new format unfolds, and you’ll not want to go back

Apple users have waited a long time for a foldable device. As far back as 2019, when Samsung unveiled the first Galaxy Z Fold model, there was hope that the iPhone would follow suit. Seven years later, as Samsung is on its eighth generation, we have Apple’s answer: the iPhone Duo.

The level of excitement for this folding phone is greater than anything I’ve seen since the original iPad, and there are certainly some interesting comparisons to be made here. The launch has also seen a revival of fun apps that show off the unique features of the Duo, much like the iBeer app of its time that used the gyro in the iPhone to empty the glass as you tipped it up and pretended to drink it, or The Elements by Theodore Gray, a periodic table app for iPad that showed off its touch capabilities.

Pre-orders of the Duo saw massive interest, with delivery dates quickly slipping into 2027 as stock ran dry. The phone has now been officially selling for over a week, and despite a small number of users reporting damaged screens, overall feedback has been good.

I’ve been using the Duo as my main phone now for just over a week, and I’m impressed with what it offers. The question is, does it do enough to justify the price, or is the iPhone 18 Pro still the best option?

While there are some things that the iPhone 18 Pro models do better, I think most people will prefer the smaller form factor of the Duo and the benefit of that massive inner screen.

How much is the iPhone Duo?

The iPhone Duo was first announced ast Apple's keynote event on 9 September 2026. Pre orders of the phone started on 16 October and it officially went on sale from 23 October.

Prices for the Duo start from £1999 in the UK or $1999 in the US. In Australia it costs from A$3499 and in Europe it's €2299.

It comes in two colours, either a Star White or Night Sky (deep blue). There are four storage options from 256GB up to 2TB. If you want the 2TB version it will cost you £3199/$3199.

Features and build

Rather than a long, thin 9x16 screen folding out to create a square central screen, the iPhone Duo is shorter and fatter. Often described as a passport format, there’s a 5.4-inch OLED screen on the front, while unfolded it reveals a 7.6-inch OLED screen inside. Both of these are at a 2:1 (or 1:2 ratio).

This is the same new format as the latest Galaxy Fold 8 and the Xiaomi 18 Fold (which is only currently available in China. This is better for watching movies than the squarer fold formats. It also makes the phone more pocket-friendly when folded, and standing at 117.8 mm in height, is actually only a couple of millimetres taller than the original iPhone.

Though smaller in dimensions (folded) than most iPhones this century, at 254g, it weighs more than the iPhone 18 Pro Max – and interestingly around the same weight as the new iPad mini.

For added strength, the Duo has a titanium frame and hinge cover, while the front display features Ceramic Shield 2 protection and the rear features Ceramic Shield – much like the iPhone 18 models. There’s no shield on the inner screen as this is protected when the phone is closed.

Buttons and functions

Flat metal buttons sit on the top and right of the phone’s back section when folded, and remain in that position when open and held horizontally. Volume buttons are at the top while the two side buttons are the power/lock/siri button and a camera control button, which provides quick access to the camera, then features touch sensitivity to adjust settings and takes pictures with a press.

There’s no action button on the Duo, so to mute the phone you must press on the new integrated battery, data signal and WiFi strength icon to access the quick control panel –or pull down from the top right corner.

One big omission here is Face ID. Instead, the power button provides Touch ID control, much like on most iPad devices and on Macs. It seems a strange step back not to feature Face ID here, but the multitude of cameras and unlocking positions make it far more complex. The Touch ID can be easily configured for multiple fingers, and you can also automatically unlock the Duo with your Apple Watch, so it’s not really a problem day to day.

There’s no SIM card tray on the Duo, either. Like the iPhone Air you have to use an eSIM. In the US, the iPhone 18 Pro models are also eSIM-only, so it feels like it’s a natural phasing out of the physical SIM by Apple. In many ways, eSIMs are much easier anyway, provided the network is quick to swap over your device.

Displays

The two displays on the Duo are very different, not just in size but also appearance. The outer display is a 5.4-inch Super Retina XDR OLED display, which is around 80mm high by 115mm wide. The edges are curved on the right but square on the left, and as such Apple has moved all the bits that would normally sit at the top and bottom of your screen to that section on the right to remove as much dead space as possible.

Practically, though, that means that you have a regular 9x16 phone working area equivalent to about a 5-inch display. That’s slightly smaller than the iPhone 13 mini (5.4-inch) and a little larger than the iPhone SE 2 (4.7-inch).

Unfolded, it’s a different story; the 7.6-inch screen is the largest display of any iPhone to date, with around 32% more pixels than the 6.9-inch iPhone 18 Pro Max. Most of that, of course, comes in width from the squarer format.

This is also a Super Retina XDR display with an 1876x2670 pixel resolution. It also gets a nano-texture finish to provide that matte look, removing reflections and giving a paper-like feel. This, like the front display, has Apple’s ProMotion technology for adaptive refresh rates up to 120Hz, and a brightness from just 1 nit up to 3,000 nits peak for outdoor use.

As for the crease, it’s one of the least visible of any folding phone to date. It’s not completely invisible when the screen is off, and I’m sure over time it will become a little more obvious, but while using the inner screen you’d struggle to spot it.

Cameras

On the back of the iPhone Duo (when folded) are two 48MP Dual Fusion cameras. A main 26mm 1x zoom and a 13mm 0.5x zoom, both f/2.2. You also get a 2x zoom at 12MP through a crop on the main camera sensor. There’s no telephoto camera here, though, nor is there the new variable aperture option like on the iPhone 18 Pro models.

There are two different front-facing cameras on the Duo. On the outer screen, there’s a 12MP centre stage camera with an f/2.2 aperture. On the large inner screen, it features an under-display camera for the first time on an Apple product and is mostly invisible when the screen is on. This is a 4MP camera with an f/1.8 aperture, which is considerably lower resolution than we’re used to on an iPhone. However, it still offers Centre Stage for video calls and offers video recording at up to 1080p at 30 or 60fps.

The outer front-facing camera provides 4K Dolby Vision recording at frame rates from 24 to 60fps, as well as Cinematic mode in 4K 30fps and slow motion in 1080p at 120fps. The main Fusion camera on the back also offers 100 and 120fps shooting in 4k, slow mo at 240fps in 1080p and the ultra-stabilised Action mode at 2.8k in 60fps. It’s also possible to do dual capture in 4k 30fps, using the front (outer) camera and the rear cameras.

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Results from the rear main and ultra-wide camera look incredible, especially when viewed nice and large on the inner screen. There’s great detail and colour, and noise is well controlled, especially at 24MP. The outer front camera also performs well. It’s not as adaptable as the 18MP model on the 18 Pro models (or even the 17 Pro models) but it’s plenty good enough for quick snaps.

The under-screen camera on the inner screen is also not terrible. The colour and exposure are well controlled and even shadows are handled admirably. It does however lack detail, and viewed on the inner screen you can see it’s only a 4MP picture – or 2MP if you use the closer crop. It’s fine for video calls, but not much else.

Luckily, you can use the rear cameras for most things. Even for selfies using the smart take function or with the live preview that can be shown on the outer screen while

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Battery

The Duo uses dual lithium-ion batteries for power – one in each half of the phone and as such, manages to offer impressive battery life. It’s quoted at around 24 hours for general use, or up to 31 hours video playback using the inner display. That’s similar to the iPhone 18 Pro though less than the Pro Max. In general, I’ve found that figure to be about right and normally land at about 50% after 12-15 hours in use.

It does provide fast charging of up to 60W with a compatible wired charger, or 35W with a compatible wireless charger. I have found wireless charging plates, like those in the car, can cause the Duo to get very warm, but on USB-C and home MagSafe and Qi2 docks it stays pretty cool.

In use

The really interesting thing about the Duo is how even small changes in the iOS layout can affect how you use the phone. The inner screen is really impressive when you really want to look at something, whether it’s a photo or a TV show, or even a website. It’s also great for editing video and gaming, provided the game has been updated for the new screen.

At this time Candy Crush, Gardenscapes, Bridge Constructor and Pokémon Go have not. Though the racing game Asphalt and new additions such as Battlefleet Duo look incredible.

For a lot of my time, I ended up using the outer screen more than I expected. The screen size reminded me of being back on my iPhone 13 mini (a phone I loved), and actually it’s more than enough display for emails, messages and social feeds. The wider display also makes typing on the virtual keyboard easier, as you get nice big buttons.

The one thing that constantly confused me was having the back button in the column along the right-hand side, instead of in the top left, where it would sit on single-screen iPhones. This comes from years of using a very similar operating system, and I’m sure over time you would get used to it. The same goes for the dock, which sits in the right-hand column. The number of times I’ve gone to the bottom to find my quick links and realised they are not there. I imagine given another few weeks, though, this wouldn’t be an issue.

The best thing for me is that you can have a small phone in your pocket again with the Duo, without missing out on the big screen experience. In fact, the inner screen is so good, it might also replace my iPad mini for watching films on shorter flights.

The one thing I did find with the Duo is that when I closed the phone and placed it in my pocket, it was often still unlocked, so the front screen would activate. This isn’t an issue if you have a folio case, but you can also create a shortcut action to automatically lock the phone when it closes, which completely solves the problem.

I haven’t had a chance to try the Duo with the Apple Pencil as yet, as it only works with the USB-C model, not the more premium Apple Pencil Pro, which I use with the iPad Pro. If you want to use the screen for editing or drawing, though, it’s a great function to have.

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Apps

While the Duo is still very much an iPhone and runs on the iOS platform, the dual-screen nature has required some serious reimagining, both from Apple and from third-party app producers. This has led to new fun apps and often new ways of working.

There’s been a spate of apps to make use of the new dual-screen and folding screen arrangement. Some of my favourites have been the Battlefleet Duo, a modern version of the Battleships game, Pianofold, for a piano-inspired Guitar Hero-like experience, and Deck-Man, which turns your phone into an 80s-style portable cassette player.

A week in, we’re already seeing more apps making use of the screens properly. Older apps not updated for the Duo have a small black bar along the side of the front screen and sit in the centre of the rear screen, either when held horizontally or vertically. Though there’s an option to expand to fill the screen, as there used to be on iPhone apps used on an iPad in the early days.

I suspect that within a month, most major apps will have updated to make use of the Duo screens properly. Certainly by the time we hit the Christmas holidays, it will cease to be an issue.

Should I buy the iPhone Duo?

If you’ve been longing for Apple to make a foldable iPhone for as long as I have, you’re going to love the Duo. Apple has made a very premium, very Apple interpretation of a folding phone that feels incredibly positive in the hand. It has also made some clever adaptations to iOS to make it work with this new form factor.

In-house apps demonstrate how well the new real estate can be utilised, and as third-party developers update their own apps, we will see more and more clever uses, and reasons to unfold to see them on the bigger screen.

While I could mention the price, which some have claimed is too high, it doesn’t seem that relevant here. Firstly, it was always expected to be around this price and hasn’t stopped the mass of pre-orders. Yes, it’s the most expensive iPhone to date, but it’s also the most innovative. Plus, if you want to justify it, just factor in the cost of an iPad, which you will no longer need.

The Duo isn’t perfect; the under-screen camera still feels like a bit of a compromise, and the lack of Face ID feels at odds with the premium nature of the device. However, these feel like small sacrifices for what is an incredible phone and, by far, the best model to buy this year.