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.

San Ardo, CA

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
831-221 A   515J IP HORIZON LLC 736      
831-221 0   981E BANDWIDTH.COM CLEC, LLC - CA 736   2010-08-30   
831-221 1   515J IP HORIZON LLC 736      
831-221 2   515J IP HORIZON LLC 736      
831-221 3   073H TELNYX LLC 736   2018-07-03   
831-221 4   515J IP HORIZON LLC 736   2022-10-20   
831-221 5   8826 LEVEL 3 COMMUNICATIONS, LLC - CA 736   2005-07-31   
831-221 6   981E BANDWIDTH.COM CLEC, LLC - CA 736   2015-10-15   
831-221 7   515J IP HORIZON LLC 736   2022-10-20   
831-221 8   981E BANDWIDTH.COM CLEC, LLC - CA 736   2014-03-28   
831-221 9   373F PEERLESS NETWORK OF CALIFORNIA, LLC - CA 736   2016-03-05   
831-303 A MTRYCAPMDS0  373F PEERLESS NETWORK OF CALIFORNIA, LLC - CA 736      
831-303 0   373F PEERLESS NETWORK OF CALIFORNIA, LLC - CA 736      
831-303 1   073H TELNYX LLC 736   2021-02-26   
831-303 2   373F PEERLESS NETWORK OF CALIFORNIA, LLC - CA 736      
831-303 4   776C CHARTER FIBERLINK CA-CCO, LLC - CA 736   2024-06-09   
831-627 A SNARCA11RS1  9740 PACIFIC BELL 736      
831-627 1   9740 PACIFIC BELL 736      
831-627 2   9740 PACIFIC BELL 736      
831-627 3   9740 PACIFIC BELL 736      
831-627 4   516C AT&T CORP. 736   2011-09-26   
831-627 5   9262 UTILITY TELECOM GROUP, LLC - CA 736   2006-06-14   
831-627 6   649C ONVOY, LLC - CA 736   2017-04-27   
831-627 7   508J CENTURYLINK COMMUNICATIONS, LLC 736   2015-11-09   
831-627 8   671J U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 736   2016-03-20   
831-732 A SLNSCA01XXX  8826 LEVEL 3 COMMUNICATIONS, LLC - CA 736      
831-732 0   649C ONVOY, LLC - CA 736      
831-732 1   649C ONVOY, LLC - CA 736   2021-07-30   
831-732 3   649C ONVOY, LLC - CA 736   2019-07-28   
831-732 4   8826 LEVEL 3 COMMUNICATIONS, LLC - CA 736   2014-04-12   
831-732 5   649C ONVOY, LLC - CA 736   2010-11-28   
831-732 7   649C ONVOY, LLC - CA 736   2019-09-13   
831-732 8   624H ONVOY SPECTRUM, LLC 736   2024-01-05   
831-732 9   6006 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 736   2024-07-22   

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

Sponsored by: VoIP Much Phone Company

Like this site? We accept donations via PayPal.