iPhone Duo FAQ: Apple Pencil, Touch ID, Apps, SIM Support, and More

Can you use an Apple Pencil with iPhone Duo? Does it run iPad apps? And what do you give up compared with an iPhone 18 Pro? Apple's first foldable brings a larger screen and new ways to use it, but the details matter on a phone that starts at $1,999.

Here are the answers to the questions most likely to come up before pre-orders open on October 16, from the two displays and cameras to eSIM and charging.

When Can You Buy iPhone Duo, and What Does It Cost?

U.S. pre-orders begin Friday, October 16, at 5 a.m. Pacific / 8 a.m. Eastern. Availability starts Friday, October 23, in the first wave of markets, with additional countries following October 30.

You can get ready on Apple's website now by choosing your phone ahead of time, then complete checkout when pre-orders open on Friday.

U.S. prices are $1,999 for 256GB, $2,199 for 512GB, $2,599 for 1TB, and $3,199 for 2TB. All four capacities come in Star White or Night Sky. Duo ships with iOS 27.1.

How Big Are the Screens?

The inner display measures 7.6 inches diagonally when opened, while the outer screen is 5.4 inches. Apple says the inner display has 50 percent more screen area than iPhone 18 Pro Max, and the outer display has over 90 percent of iPhone 18 Pro's screen area. The short, wide shape gives you more room than that 5.4-inch diagonal might suggest.

Both are OLED Super Retina XDR displays with ProMotion up to 120Hz, Always-On support, and up to 3,000 nits of outdoor brightness.

Duo measures 117.8 mm high and 164.6 mm wide when open, at 5.2 mm thick. Folded, the width shrinks to 84.1 mm and the thickness increases to 11.3 mm. It weighs 254 grams, so although it is short enough to fit in a pocket, it is still a substantial phone.

Does the Folding Screen Have a Crease?

Yes. Apple uses a nano-textured finish on the inner display to reduce glare and make the crease less noticeable.

Apple has also confirmed that the screen's cover layer can be replaced if it wears over time. A fresh layer may make the crease less conspicuous again, but it does not remove the fold beneath it. Apple has not announced a do-it-yourself replacement process.

Does iPhone Duo Support Apple Pencil?

Apple Pencil (USB-C) will work on both Duo displays for notes, sketches, and markup. Support is coming later in 2026, with no launch-day commitment. Apple Pencil Pro is not compatible.

Does It Have Face ID?

No. Duo uses a fingerprint sensor in the side button for Touch ID, accessible with the phone open or closed. You can also unlock it with an Apple Watch.

Can It Run iPad Apps or Two Apps Side by Side?

It can run two iPhone apps side by side, but not iPad-only apps. Duo runs iOS 27.1, with layouts designed for its folding screen rather than the iPadOS interface.

Split View puts two apps on the inner screen. You can also open two windows of a supported app, such as Safari, and save app pairs. Apple's own apps are adapted for Duo, as are third-party apps including Netflix, Zoom, and Slack.

Developers can rearrange controls and show more content when the phone opens, as Apple's Duo app guidance explains. If you're hoping to leave a tablet behind, our iPhone Duo vs. iPad mini guide looks at where it can take over and where a separate iPad still helps.

Does iPhone Duo Support Siri AI?

Yes. Duo's A20 Pro chip supports Apple Intelligence and Siri AI, so you can have back-and-forth conversations and ask Siri to find information in your photos, mail, and notes.

Siri AI is in beta, with English support to start. Apple's initial rollout excludes iOS users in the EU, and daily usage limits apply to Siri AI and some other cloud-based AI features.

Is the Camera the Same as iPhone 18 Pro?

No. Duo has a 48MP Fusion Main camera and a 48MP Fusion Ultra Wide, but no dedicated long-range Telephoto. Its optical-quality 2× option uses a crop from the Main sensor.

The Main camera has a fixed f/1.6 aperture, rather than the variable aperture on iPhone 18 Pro and Pro Max. Duo also lacks their ProRAW and ProRes capture options. The Pro models offer more flexibility for photographers who want those controls and formats.

Duo has some tricks of its own. Duo Preview lets the person being photographed see the shot on the outer screen. Smart Take captures photos automatically when people are posing, while Kid Cue plays animations to attract a child's attention.

For the broader trade-offs, read our iPhone Duo vs. iPhone 18 Pro Max comparison.

What Is the Camera Under the Inner Screen For?

The under-display FaceTime camera is for video calls and recording with Duo open or propped up. It supports 1080p at 30 or 60 fps; Apple has not disclosed its megapixel resolution.

The outer screen has a separate 12MP Center Stage camera. You can also take selfies with the rear cameras and use that outer screen to frame the shot.

Does It Take a Physical SIM?

No. Duo is eSIM-only worldwide, with two active eSIMs and storage for eight or more. If you normally buy a physical local SIM while traveling, you will need an eSIM option instead.

Wireless connections include 5G, Wi-Fi 7, and Bluetooth 6. The USB-C port supports data transfers up to 10Gb/s with a compatible USB 3 cable, as well as charging.

How Do Charging and Battery Life Work?

The box includes a 1-meter USB-C charging cable, but no power adapter or MagSafe Charger. Those are separate purchases if you don't already have suitable ones.

Duo supports USB-C charging and up to 25W MagSafe or Qi2 wireless charging. Apple's wired fast-charge rating is up to 50 percent in around 20 minutes with a 60W-capable USB-PD adapter and a 60W-capable USB-C cable, tested with the phone open. With a MagSafe Charger and a 35W-or-higher adapter, the rating is up to 50 percent in around 30 minutes.

Using the smaller screen saves power. Apple's video-playback ratings are up to 44 hours on the outer display or 31 hours on the inner one; streamed video is rated at 37 and 26 hours, respectively. For typical use split equally between the screens, Apple quotes up to 24 hours. Actual battery life will vary with your apps, settings, and signal.

Is iPhone Duo Water Resistant?

Duo is rated IP68, tested at a maximum depth of six meters for up to 30 minutes. Water resistance can decline over time; it is not designed for swimming or underwater photography.

Can It Stand Up Without a Case?

You can prop Duo up on its hinge for calls or video capture. StandBy works on either display without connecting a charger, turning the phone into a clock, photo frame, or widget display. Apple's Folio with Kickstand provides another way to support it at an angle.