T-Mobile will charge customers $5 per month to use iPhone Handoff, an eSIM feature allowing the same phone number on two separate iPhones. At launch, only T-Mobile users in the U.S. and Deutsche Telekom users in Germany can access the feature. Customers can use their number across two compatible iPhone models and choose which device is active. Features like calls, texts, data, mobile hotspot, Scam Shield, and T-Satellite will work on both devices with an eligible plan.

Apple is adding support for iPhone Handoff in iOS 27. It requires two iPhones running iOS 27 or later, connected to Wi-Fi, and signed into the same Apple Account with FaceTime, iMessage, and Messages in iCloud enabled. The feature can be activated during new iPhone setup or in the Settings app. When enabled, one iPhone serves as the main device while the other acts as a secondary device sharing the same number. Switching between devices happens automatically when unlocking either iPhone.

A phone number can only be active on one iPhone at a time. Payment cards in Wallet and car keys can work across both iPhones, though some Wallet items like transit passes, IDs, or corporate badges may only function on one device. iPhone Handoff does not transfer an Apple Watch between iPhones. The feature works with Dual SIM as long as both eSIMs come from carriers supporting iPhone Handoff. iOS 27 launches Monday, September 14, with new iPhone 18 Pro models arriving Friday, September 18.