Apple's iPhone Handoff feature will cost you $5 a month on T-Mobile

The ability to use one SIM across two handsets will be available with iOS 27.

Apple is launching a new feature called iPhone Handoff with iOS 27 that will give you a way to use the same eSIM number on two devices. It will initially be available to T-Mobile customers in the US and to Deutsche Telekom users in Germany. Now, T-Mobile has announced that it will cost subscribers an additional $5 a month if they want to be able to access the feature. What a shame there isn't some sort of un-carrier who eliminates these sorts of nickel-and-dime fees from its service.

It's worth noting that the phones can't use the same number at the same time. T-Mobile subscribers will be able to choose which phone is active at any given time, and they will be able to switch devices any time they want. Their calls, voicemail, messages and Find My will automatically move to whatever iPhone they're currently using. Their iCloud data and third-party apps also sync across devices.

Users can set up iPhone Handoff either through Settings on their current device or when they activate a new iPhone. In their newer phone, they have to go to Cellular in Settings and then tap either Set up Cellular or Add eSIM. They then have to select an iPhone > Continue > Transfer. After they follow the onscreen prompts on both devices, they only have to unlock the iPhone they want to use. A message that says "Switched to this iPhone" will appear at the top of their screen to confirm that the device is currently using their number.

To be able to use iPhone Handoff, both devices must be running iOS 27 and share the same Apple ID. Apple is rolling out iOS 27 on September 14.