Apple introduced iPhone Handoff last month with the Duo, and the iPhone Duo pre-order pitch now includes one number staying active on two iPhones. T-Mobile is the first US carrier to support it, and the feature adds $5 to the monthly phone bill.
That setup gives a single number to a main phone and a secondary phone. When one of the phones is unlocked, the number moves to that device, so calls and Find My follow the active handset.
T-Mobile and the $5 fee
T-Mobile’s launch makes it the first US carrier to offer iPhone Handoff, but the service is not free. The extra $5 monthly charge turns a convenience feature into an ongoing subscription decision for anyone comparing it with just carrying one line or swapping an eSIM.
Apple’s own framing suggests the feature is for people who need two phones but do not want two phone numbers. It also points to people who want better battery life and cameras than an iPhone Mini or iPhone Air, which makes the trade-off less about novelty and more about whether the second device earns its keep.
AT&T and business limits
AT&T is not supporting iPhone Handoff at launch, and Verizon is planning support by the end of the year. The secondary iPhone should not have any other service attached to it, and it cannot be used with a T-Mobile business account at launch.
That combination matters because the feature is only useful where the carrier and account rules allow it. A customer who wants the setup now has one carrier choice, one monthly fee, and several restrictions that narrow the pool beyond Apple’s broad pitch.
Apple’s iPhone Handoff pitch
The practical question is whether enough people will pay $5 each month for the convenience of one number on two iPhones. For anyone already managing a personal phone and a second handset, the appeal is clear; for everyone else, the restrictions may be enough to push them back to eSIM switching or a single-device setup.
What remains to watch is whether Verizon’s support by the end of the year makes the feature feel like a wider option or just a more expensive corner case.
