Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
  • Effective date searches are available only for US area codes. Our sources for non-US NPA-NXX data do not provide this information.
  • If you want to search an entire area code regardless of activity, leave both the next and past days fields set to zero.

NPA: 520 [Rate centres in NPA 520] [Dial plan for NPA 520]

NXX: 257

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
520-257 A Tucson AZ TCSMAZOI3MD  6529 T-MOBILE USA, INC. 668      
520-257 0 Tucson AZ TCSMAZCH1MD  6010 NEW CINGULAR WIRELESS PCS, LLC 668   2014-10-25   
520-257 1 Tucson AZ TCSNAZXGDS0  7465 MCIMETRO ACCESS TRANSMISSION SERVICES LLC - AZ 668   2014-10-21   
520-257 2 Tucson AZ TCSNAZMAVMD  3285 LEVEL 3 COMMUNICATIONS, LLC - AZ 668   2014-10-21   
520-257 3 Tucson AZ TCSNAZMAVMD  3285 LEVEL 3 COMMUNICATIONS, LLC - AZ 668   2014-10-21   
520-257 4 Tucson AZ TCSNAZMAVMD  3285 LEVEL 3 COMMUNICATIONS, LLC - AZ 668   2014-10-21   
520-257 5 Tucson AZ TCSMAZOI3MD  6529 T-MOBILE USA, INC. 668   2014-10-18   
520-257 6 Tucson AZ TCSMAZOI3MD  6529 T-MOBILE USA, INC. 668   2014-10-18   
520-257 7 Tucson AZ TCSMAZOI3MD  6529 T-MOBILE USA, INC. 668   2014-10-18   
520-257 8 Tucson AZ TCSMAZOI3MD  6529 T-MOBILE USA, INC. 668   2014-10-18   
520-257 9 Tucson AZ TCSMAZOI3MD  6529 T-MOBILE USA, INC. 668   2014-10-18   

Last updated: Wed, 18 Jun 2025 02:30:00 UTC

Sponsored by: BeeVox - Whitelabel Reseller Platform

Like this site? We accept donations via PayPal.