VOICE CALLING: If you have a voice-capable device (unless you request voice blocking, select a data plan that restricts voice access or select a qualified voice plan), the default rate for voice calls on AT&T’s wireless network is $0.40 per minute and $0.69 per minute for domestic roaming voice calls off AT&T’s wireless network. See AT&T Nation map for default voice coverage area.
per
Available Data Rate Plans | AT&T wireless services