Apple’s new iPhone Handoff feature, which lets two iPhones share a single phone number and automatically switch between them, will launch with support from only two carriers: T-Mobile in the United States and Deutsche Telekom in Germany.
Apple unveiled the feature at its September 9 event alongside the iPhone Duo and confirmed it in iOS 27 release materials.
While the capability itself has been in development since WWDC 2026, Apple’s carrier agreements at launch are narrow, leaving customers on AT&T, Verizon, and most other networks without access when iOS 27 ships on September 14.
How it works
With iPhone Handoff enabled, one device is designated the primary iPhone and the other becomes a secondary that shares the same number.
When you unlock either phone, your number automatically becomes active on that device, and a “Switched to this iPhone” message confirms the change.
Only one phone can hold an active call or receive messages at a time, but the transition requires no manual steps beyond picking up the device you want to use.
Setup requires both iPhones to run iOS 27, connect to Wi-Fi, and be signed into the same Apple account, with FaceTime, iMessage, and Messages in iCloud all turned on.
You can configure the feature during new iPhone setup or later in the Settings app. Apple notes there may be carrier fees involved, though T-Mobile has not announced pricing.
What carries over and what doesn’t
Payment cards and car keys stored in Wallet work across both devices, but Apple warns that some Wallet items, including transit passes, government IDs, and corporate badges, may work on only one iPhone at a time.
Certain carrier features like Call Forwarding, Caller ID, and account management are locked to the primary device only.
Apple Watch does not transfer between devices when iPhone Handoff switches, which means users who swap regularly will still need to manage their watch connection manually.
The omission is frustrating because Apple’s existing process for moving an Apple Watch between iPhones remains unnecessarily cumbersome.
For users with Dual SIM setups, both eSIMs switch together when you unlock a device, provided both carriers support the feature.
Each eSIM still requires separate configuration. Once activated, iPhone Handoff remains enabled until the user contacts their carrier to disable it.
Apple has not said when or whether it will add more carriers. For most iPhone users in the U.S., the feature won’t be available at launch, and there is no public timeline for a broader rollout. T-Mobile customers can access it starting September 14, once iOS 27 is publicly released.
