T-Mobile is launching Apple's new iPhone Handoff feature for compatible iPhones. This allows customers to use their T-Mobile number across two iPhones and choose which device is active. The secondary iPhone will support calls, texts, data, mobile hotspot, Scam Shield, and T-Satellite. iPhone Handoff requires iOS 27 and will be available on the new iPhone 18 Pro and iPhone Duo models from launch day. T-Mobile is charging a monthly fee of $5 for this service. The author argues this fee is excessive, as switching eSIMs between devices can currently be done for free, albeit with more manual steps. They express no surprise at a carrier charging for such a feature. The author also notes AT&T has not yet announced support for iPhone Handoff. They criticize AT&T's network and customer service, suggesting users with poor AT&T signal should consider alternatives.