Apple is preparing a handy new feature for people who juggle two iPhones. Called iPhone Handoff, it will let a single phone number move between two devices, with the feature set to arrive alongside iOS 27, expected later this month. Apple only briefly mentioned the feature during its WWDC 2026 keynote in June, without explaining how it would actually work in practice, leaving many of the finer details to emerge only recently through community testing.
A MacRumors forum member recently shared a detailed demonstration of the feature, simulating two iPhones using Device Hub in Xcode 27 to reveal the setup process clearly. According to the demonstration, the system relies on eSIM technology rather than cloning a physical SIM card. Users first designate one iPhone as the main device, which keeps the existing eSIM tied to their number, while the second iPhone becomes a companion device that receives a companion eSIM linked to the same number, allowing both devices to share access to a single line without requiring a physical SIM swap.
The switching between devices happens automatically based on usage, with the number following whichever iPhone is unlocked and actively being used at any given time. A notification appears in the Dynamic Island whenever the number switches devices, giving users a clear indication of which phone is currently active for calls and messages. Location sharing also follows the active phone, meaning contacts using Find My will see whichever device is currently carrying the line rather than a fixed device. Users set up the feature through the Settings app under Cellular, with the main iPhone retaining control over all cellular settings while the companion phone does not receive independent cellular management, suggesting Apple has designed the pairing as asymmetric rather than treating both devices as fully equal.
The practical benefits of the feature are fairly clear for certain types of users, such as someone who wants to keep a newer iPhone as their full time device while using an older one for travel or exercise, without risking loss of access to banking or work apps tied to their primary number. However, one significant limitation could affect how widely the feature is adopted, since iPhone Handoff depends entirely on carrier support to function, requiring mobile networks to build companion eSIM provisioning into their backend systems. Reports suggest that T-Mobile in the United States and Deutsche Telekom in Germany could be among the first carriers to support the feature, though Apple has not yet published a full list of supported carriers. As a result, availability of iPhone Handoff in markets such as Pakistan remains uncertain for now, and both iPhones involved will also need to be running iOS 27 for the feature to function at all.
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