One Phone Number for Two iPhones: iOS 27 Features Quick Switching via iPhone Handoff
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05.09.2026 20:30
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2 min read
Test builds of iOS 27 feature a new function called iPhone Handoff. The feature addresses a long-standing issue for multi-device Apple users by allowing them to quickly switch a single cellular number between two smartphones, eliminating the need to re-configure and transfer an eSIM profile each time.
How the Companion eSIM Profile Works
iPhone Handoff does not work like the common concept of “one SIM card for two phones at once.” As MacRumors notes, the phone number will not be active on both devices simultaneously.
The system’s architecture resembles how an iPhone pairs with a cellular Apple Watch:
- The primary digital SIM card remains on the main smartphone;
- A paired Companion eSIM profile tied to the same billing account is downloaded to the second device;
- In system settings, one phone is designated as primary and the other as secondary, allowing cellular service to be transferred between them manually or automatically.
Calls, SMS, and mobile data function only on the device that currently holds priority. This fundamentally alters the user experience: currently, according to Apple Support documentation, activating a number on a second device immediately deactivates the card on the first.
Carrier Requirements
iPhone Handoff was first briefly shown in the changelog at WWDC 2026, but interface details have only now surfaced. A user going by pdfu on the MacRumors forums showed live setup screens by running a dual-smartphone simulation in Device Hub for Xcode 27.
Carrier support will be the key obstacle to using the new feature. Updating to iOS 27 alone will not be enough: carriers must support issuing paired digital profiles on their end for the feature to function.
Announced at WWDC26, iOS 27 will support switching between two iPhone devices with the same phone number.
— pdfu (@itspdfu) September 2, 2026
The feature will be called iPhone Handoff. Here's a demo of the setup. pic.twitter.com/1ZwoPC7PaK
Apple has not yet released an official list of telecom companies supporting iPhone Handoff. Detailed compatibility lists and plan terms are expected closer to the public release of the final iOS 27 build in September.
