← Area code 830
830-366 phone numbers
Numbers 830-366-0000 to 830-366-9999 are assigned to T-Mobile USA, Inc. in Pleasanton, TX. 5 of its ten thousand-number blocks are assigned to other carriers (number pooling).
Not assigned to any carrier: 830-366-8xxx — calls from these use spoofed caller IDs.
Source: North American Numbering Plan Administrator, Nov 3, 2026. Numbers can move between carriers.