NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.

Most active assignees, all time — NPA 310
PACIFIC BELL 250
FRONTIER CALIFORNIA INC. 137
NEW CINGULAR WIRELESS PCS, LLC 68
T-MOBILE USA, INC. 58
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 56
New assignments by month Sep 2026 Aug 2026 Jul 2026 Jun 2026 May 2026 Apr 2026 Mar 2026 Feb 2026 Jan 2026 Dec 2025 Nov 2025 Oct 2025
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Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2025-11-20 310-731 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - CA 649C SAN PEDRO CA
2024-02-14 310-757 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CMTN CMTN CA
2023-06-26 310-304 0–9 XXXwhole prefix which blocks → ONVOY, LLC - CA 649C LOMITA CA
2023-06-26 310-708 0–9 XXXwhole prefix which blocks → ONVOY, LLC - CA 649C MALIBU CA
2023-06-26 310-758 0–9 XXXwhole prefix which blocks → ONVOY, LLC - CA 649C SAN PEDRO CA
2023-06-26 310-759 0–9 XXXwhole prefix which blocks → ONVOY, LLC - CA 649C HAWTHORNE CA
2023-06-22 310-269 0–9 XXXall 10 · 5 holders which blocks → UTILITY TELECOM GROUP, LLC - CA 9262 BEVERLYHLS CA
2020-12-11 310-290 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 BEVERLYHLS CA
2020-10-13 310-810 0–9 XXXall 10 · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E CMTN CMTN CA
2020-08-28 310-565 0–9 XXXall 10 · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CA 7139 EL SEGUNDO CA
2017-07-03 310-682 0–9 XXXwhole prefix which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CA 7139 HAWTHORNE CA
2017-03-08 310-620 0–9 XXXall 10 · 5 holders which blocks → INTEGRATED PATH COMMUNICATIONS, LLC - CA 707H BEVERLYHLS CA
2017-01-16 310-340 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 HAWTHORNE CA
2017-01-16 310-554 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 CMTN CMTN CA
2013-01-14 310-905 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 SNMN MRVS CA
2012-10-09 310-627 0–9 XXXall 10 · 7 holders which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F CMTN CMTN CA
2012-10-04 310-504 0–9 XXXall 10 · 5 holders which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F REDONDO CA
2012-10-02 310-307 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 W ANGELES CA
2012-08-14 310-879 0–9 XXXall 10 · 7 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E CMTN GRDN CA
2012-08-13 310-299 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 BEVERLYHLS CA
2012-08-13 310-730 0–9 XXXall 10 · 6 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E CULVERCITY CA
2012-08-08 310-596 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 CULVERCITY CA
2012-05-22 310-870 0–9 XXXall 10 · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E REDONDO CA
2011-08-23 310-912 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 INGLEWOOD CA
2011-06-08 310-976 not yet reported which blocks → NORTH COUNTY COMMUNICATION CORPORATION - CA 7894 BEVERLYHLS CA
2011-02-22 310-935 0–9 XXXall 10 · 7 holders which blocks → ONVOY, LLC - CA 649C SAN PEDRO CA
2010-12-10 310-853 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E CULVERCITY CA
2006-11-07 310-310 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 SNMN SNMN CA
2006-02-02 310-424 0–9 XXXall 10 · 4 holders which blocks → PAETEC ITEL, LLC 829J BEVERLYHLS CA
2005-12-29 310-775 0–9 XXXall 10 · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 W ANGELES CA
2005-09-29 310-294 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 TORRANCE CA
2005-09-29 310-295 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 W ANGELES CA
2005-09-29 310-425 0–9 XXXall 10 · 7 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CULVERCITY CA
2005-09-08 310-848 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAWTHORNE CA
2005-09-08 310-988 0–9 XXXall 10 · 7 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 INGLEWOOD CA
2005-08-30 310-982 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 SAN PEDRO CA
2005-08-03 310-961 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 TORRANCE CA
2005-05-10 310-703 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 INGLEWOOD CA
2005-03-22 310-256 0–9 XXXall 10 · 3 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 INGLEWOOD CA
2005-02-23 310-653 0–9 XXXwhole prefix which blocks → PACIFIC BELL 9740 EL SEGUNDO CA
2005-02-22 310-561 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 TORRANCE CA
2005-02-14 310-987 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 SAN PEDRO CA
2005-01-03 310-986 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LOMITA CA
2004-11-17 310-984 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 SAN PEDRO CA
2004-11-08 310-654 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 INGLEWOOD CA
2002-10-17 310-985 6XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 SNMN SNMN CA
2002-09-06 310-430 7XXX which blocks → T-MOBILE USA, INC. 6529 SNMN SNMN CA
2002-08-21 310-951 not yet reported which blocks → T-MOBILE USA, INC. 6529 TORRANCE CA
2002-07-29 310-948 0XXX1XXX2XXX3XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 W ANGELES CA
2002-06-14 310-946 0XXX1XXX2XXX8XXX9XXX · 3 holders which blocks → METROPCS NETWORKS, LLC 899D INGLEWOOD CA

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.