331-284 phone numbers

Numbers 331-284-0000 to 331-284-9999 are assigned to T-Mobile USA, Inc. in Bartlett, IL. 8 of its ten thousand-number blocks are assigned to other carriers (number pooling).

Not assigned to any carrier: 331-284-8xxx — calls from these use spoofed caller IDs.

Source: North American Numbering Plan Administrator, Nov 3, 2026. Numbers can move between carriers.

Reported numbers in 331-284