If you switch between two iPhones regularly, you no longer need separate carrier accounts for each. iPhone Handoff, introduced in iOS 27 and detailed at Apple's Surprise and Shine event on September 9, lets you use the same phone number across two iPhones. Once set up, simply unlock the iPhone you want to use and you're ready to go. Handoff supports calls, messages, payment cards, and most apps with iCloud sync.

There are some limitations: your carrier must support iPhone Handoff, it does not switch your paired Apple Watch between devices, and some wallet items like IDs and passes won't work. Only T-Mobile in the US and Telekom in Germany have confirmed support so far, with T-Mobile charging an additional $5 monthly fee.

To set up Handoff, both iPhones must run iOS 27 or later, be on the same Wi-Fi network, and signed into the same Apple Account. One device becomes the primary with the main eSIM. Navigate to Settings > Cellular, tap Set Up Cellular/Add eSIM or iPhone Handoff, choose Use Number on This iPhone and Another, and follow the prompts. When replacing a device, transfer the eSIM to the new one.

iPhone Handoff is a niche but useful feature for migrating between old and new iPhones, traveling with a secondary device, or separating work and personal use.