A new feature in iOS 27, called iPhone Handoff, allows users to use the same phone number across two iPhones. This means users can make calls and send messages from either device without needing separate phone numbers or carrier accounts. The feature was first introduced at Apple's WWDC event and was later explained in more detail during the Surprise and Shine event on September 9. Once set up, users can unlock either phone and use the same number seamlessly. Additional benefits include the ability to add payment cards on one device and use them on both, along with smooth integration with most apps and iCloud. However, there are some limitations. The feature requires carrier support, and not all carriers currently offer it. For example, only T-Mobile in the U.S. and Telekom in Germany have confirmed support so far. T-Mobile charges an extra $5 per month for this feature. iPhone Handoff also does not transfer the Apple Watch between devices, and some items in the Wallet app, like IDs or passes, may not work on both phones. Despite these restrictions, most features function smoothly. To set up iPhone Handoff, both devices must be running iOS 27 or later, connected to the same Wi-Fi network, and signed into the same Apple account. One phone will be designated as the primary device, holding the main eSIM and managing carrier settings, while the other is the secondary phone. Both can use their eSIMs, but only if they are from supporting carriers. The setup process involves placing the two iPhones together, unlocking one, and navigating to Settings > Cellular. Users then select "Use Number on This iPhone and Another" and follow the on-screen instructions to assign one device as the main phone. If replacing an old iPhone with a new one, the eSIM must be transferred to the new device. To disable Handoff entirely, users need to contact their carrier directly. Apple designed iPhone Handoff to be as simple as unlocking an iPhone. A small notification in the Dynamic Island, just below the Wi-Fi indicator, shows when a device is activated for Handoff. While it's a niche feature, it could be helpful for users switching between old and new iPhones, traveling with a less valuable secondary device, or using a cheaper, more portable iPhone alongside a more expensive model. It may also appeal to professionals who want to separate work and personal use across different devices.