iOS 27's 'iPhone Handoff' lets one phone number live on two iPhones

When iOS 27 arrives later this month, one phone number will be able to live on two iPhones at the same time. Apple's new 'iPhone Handoff' feature — briefly teased at WWDC in June — has now surfaced in a setup demo running inside Xcode 27's Device Hub, giving the clearest picture yet of how it will work.

iPhone Handoff lets a user pair two iPhones and designate one as the 'main' device. The main phone keeps the primary eSIM; the second phone receives a 'companion' eSIM linked to the same number. From then on, the shared number follows whichever phone is currently unlocked: calls, messages and cellular data hop between devices without swapping SIMs, and a notification appears on the device where the number has just become active. Location sharing with family and friends is tied to whichever phone is currently the active one, according to the setup flow shared by a MacRumors forum member.

Users would turn the feature on in Settings > Cellular, where iPhone Handoff appears as an option when adding an eSIM.

The catch is carriers. Handoff has to be enabled on the network side as well, and references spotted in the code so far point only to T-Mobile US and Telekom.de. Support beyond those two networks is unknown, which means the feature's real-world usefulness will depend on the deals Apple strikes with individual operators.

The timing is telling. Apple is expected to unveil the foldable iPhone Ultra at its September 9 event — a large, expensive device that many owners may not want to carry everywhere. Handoff would let them leave the Ultra at home or on a desk and grab an older, smaller iPhone for the day without missing calls or messages. It also extends the continuity approach Apple already offers, where calls and texts relay to iPads, Macs and Apple Watches, one step further.

None of this is official until Apple confirms it — the details come from a demo environment, forum reports and code references — but together they paint a consistent picture of a feature arriving within weeks. The September 9 launch event is expected to confirm iOS 27's release date alongside the new hardware.