Preorders for the iPhone Duo in Korea open at 9 p.m. on October 16, and it launches on October 23, the same day as in the US. Korea is among the first-wave launch countries. At ₩3,290,000 for 256GB it costs ₩1,100,000 more than an iPhone 18 Pro Max of the same capacity, and in exchange for paying extra for a folding screen, you give up some iPhone 18 Pro features. The comparison is based on the tech specs Apple published for both models.
The iPhone Duo unfolded — Source: Apple
What changes between folded and unfolded is covered in a post from September.
🔗 Link - https://blog.naver.com/rottensweetpotato/224413012487
Price by capacity
| Capacity | iPhone Duo | iPhone 18 Pro Max |
|---|---|---|
| 256GB | ₩3,290,000 | ₩2,190,000 |
| 512GB | ₩3,590,000 | ₩2,490,000 |
| 1TB | ₩4,190,000 | ₩3,090,000 |
| 2TB | ₩5,090,000 | ₩3,990,000 |
On Apple’s online store, the iPhone Duo costs ₩3,290,000 for 256GB, ₩3,590,000 for 512GB, ₩4,190,000 for 1TB, and ₩5,090,000 for 2TB. The step-ups for more storage — ₩300,000, ₩600,000, and ₩900,000 — match the iPhone 18 Pro line, so the gap with the iPhone 18 Pro Max is fixed at ₩1,100,000 at every capacity, and the gap with the iPhone 18 Pro (from ₩1,990,000) is fixed at ₩1,300,000 at every capacity.
As of October 15, Korea’s three carriers hadn’t announced their official subsidies for the iPhone Duo. Money Today and Segye Ilbo reported that the carriers had been told their initial allocations would be small. That means short supply may limit purchases before subsidy amounts do, so whether to buy unlocked or through a carrier is best compared on a two-year total after sales terms are published at 9 p.m. on the 16th.
The full iPhone 18 Pro pricing and how it differs from the US models are in an earlier post.
🔗 Link - https://blog.naver.com/rottensweetpotato/224408275375
Weight and thickness
Weight of the three models — Source: self-rendered from Apple tech specs
The iPhone Duo weighs 254g. That’s 43g heavier than the iPhone 18 Pro (211g) and 5g off the iPhone 18 Pro Max (249g), so in the hand it feels about like the iPhone 18 Pro Max.
It’s 11.3mm thick folded and 5.2mm unfolded. The iPhone 18 Pro and iPhone 18 Pro Max are both 8.75mm, so in your pocket the iPhone Duo is 2.55mm thicker. Folded, it measures 117.8mm tall by 84.1mm wide — shorter and wider than the iPhone 18 Pro (150.0mm × 71.9mm).
Camera differences
The iPhone 18 Pro’s variable-aperture main camera — Source: Apple
The telephoto lineup is where they first diverge. The iPhone Duo has three rear cameras — 48MP main, 12MP 2x telephoto, and 48MP ultra wide — while the iPhone 18 Pro adds a 48MP 4x telephoto (100mm) and a 12MP 8x telephoto (200mm).
| Item | iPhone Duo | iPhone 18 Pro |
|---|---|---|
| Main aperture | ƒ/1.6 fixed | ƒ/1.48–4.0 variable |
| Longest telephoto | 2x (52mm) | 8x (200mm) |
| Optical-quality zoom range | 4x | 16x |
| Max digital zoom | 10x | 40x |
| Front camera | 12MP | 18MP |
The iPhone 18 Pro’s main camera changes aperture in four steps from ƒ/1.48 to ƒ/4.0, while the iPhone Duo is fixed at ƒ/1.6. If you often shoot distant subjects such as concerts or sports, you may notice the difference in telephoto reach and main-camera aperture when switching to the iPhone Duo.
What only the iPhone Duo has is a FaceTime camera (ƒ/1.8) under the inner display. There’s no hole in the screen when you video call unfolded, and it’s invisible when not in use.
Screen size
iPhone Duo outer and inner displays — Source: Apple
| Model | Display (diagonal) |
|---|---|
| iPhone Duo inner | 19.3cm (7.6 in) |
| iPhone Duo outer | 13.6cm (5.4 in) |
| iPhone 18 Pro Max | 17.4cm (6.9 in) |
| iPhone 18 Pro | 15.9cm (6.3 in) |
Unfolded, the iPhone Duo’s inner display is 19.3cm, but folded, the outer display is 13.6cm — smaller than the iPhone 18 Pro. If you do a lot folded, like replying to messages or checking maps, the screen may be narrower than the iPhone you use now. All three models share the same 3000-nit peak outdoor brightness and up to 120Hz refresh rate.
Unlocking and activation
The iPhone Duo uses Touch ID, not Face ID. The fingerprint sensor is built into the side button, while the iPhone 18 Pro uses Face ID, recognizing your face with the front TrueDepth camera. The design lets you unlock with the same button whichever screen you’re looking at as you fold and unfold.
The more direct difference for Korean users is the SIM: Apple’s Korean purchase page states that the iPhone Duo has no physical SIM tray and activates only via eSIM. The Korean iPhone 18 Pro has a SIM tray, so even bought on the same day, only the iPhone Duo activates differently.
- Check before preordering whether your carrier or MVNO plan supports eSIM activation
- You can’t move over by simply inserting your existing USIM
- A second line is registered as dual eSIM
Battery and charging
Battery life under typical use — Source: self-rendered from Apple tech specs
Maximum time under typical use is 24 hours for the iPhone Duo, 23 hours for the iPhone 18 Pro, and 29 hours for the iPhone 18 Pro Max. Even with two screens it’s about on par with the iPhone 18 Pro, and 5 hours shorter than the iPhone 18 Pro Max.
Video playback time on the iPhone Duo depends on which screen you use. Watching folded on the outer display gives 44 hours and unfolded on the inner display 31 hours, versus 34 hours for the iPhone 18 Pro and 43 hours for the iPhone 18 Pro Max.
With a 60W or higher adapter, wired charging reaches 50% in about 20 minutes on the iPhone Duo and about 15 minutes on the iPhone 18 Pro, so the iPhone Duo is 5 minutes slower. MagSafe reaches 50% in 30 minutes on both with a 35W or higher adapter, and wireless tops out at 25W on both.
What the two models share
The A20 Pro used in both models — Source: Apple
Both use the A20 Pro chip (6-core CPU, 7-core GPU). There’s no reason to choose one over the other for performance.
- Water and dust resistance: both IP68, up to 6m for 30 minutes
- Port: both USB-C, USB 3 up to 10Gb/s
- Wireless charging: both MagSafe and Qi2 up to 25W
- Storage: both in four options from 256GB to 2TB
With AppleCare+, the iPhone Duo’s accidental damage service fee is ₩40,000 per incident for the screen or back glass and ₩120,000 per incident for other damage. As a device with a hinge, it’s worth budgeting for repair costs separately.
Summary before preordering
Six differences between the iPhone Duo and iPhone 18 Pro — Source: summary of this post · self-rendered
Initial supply looks tight. Segye Ilbo reported that market research firms TrendForce and Counterpoint Research expect 2026 global iPhone Duo shipments of about 5 million and 6 million units respectively, and Money Today, citing Chinese local media, reported final-assembly yield at just over 60%. The yield figure hasn’t been confirmed by Apple.
If you rarely use telephoto, Face ID, or a physical SIM and care more about running two apps side by side on the unfolded screen, the iPhone Duo fits; if you use any of those three every day, the iPhone 18 Pro line, available the same day, is the choice that keeps more features.
Sources
- [Apple] iPhone Duo tech specs (weight, thickness, display, cameras, battery, charging, Touch ID, SIM)
- [Apple] iPhone 18 Pro and Pro Max tech specs (weight, cameras, battery, charging, Face ID)
- [Apple] Buy iPhone Duo (price by capacity, preorders, launch date, eSIM only, AppleCare+ service fees)
- [Segye Ilbo] iPhone Duo initial supply shortage expected, shipment forecasts (2026-10-15)
- [Money Today] iPhone Duo preorder allocation and yield report (2026-10-15)