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 510
PACIFIC BELL 278
NEW CINGULAR WIRELESS PCS, LLC 78
T-MOBILE USA, INC. 65
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 60
METROPCS, INC. 45
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
2026-02-25 510-310 0–9 XXXall 10 · 3 holders which blocks → SEQUOIA WIRELESS, LLC 385L HAYWARD CA
2024-09-12 510-510 not yet reported which blocks → SHELCOMM 0051 FRNK MAIN CA
2024-07-23 510-966 0–9 XXXall 10 · 3 holders which blocks → ONVOY SPECTRUM, LLC 624H RICHMOND CA
2024-06-12 510-819 0–9 XXXall 10 · 3 holders which blocks → ONVOY SPECTRUM, LLC 624H HAYWARD CA
2024-05-31 510-810 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 OKLD ALMD CA
2024-02-20 510-591 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK MAIN CA
2024-01-16 510-392 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 ELSBR-PINL CA
2024-01-04 510-546 0–9 XXXwhole prefix which blocks → ONVOY SPECTRUM, LLC 624H HAYWARD CA
2023-12-21 510-391 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK MAIN CA
2023-08-09 510-312 0–9 XXXall 10 · 4 holders which blocks → COMMIO, LLC 939H CROCKETT CA
2023-06-28 510-389 0–9 XXXall 10 · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CA 7145 OKLD TRNID CA
2021-11-18 510-721 0–9 XXXwhole prefix which blocks → ONVOY, LLC - CA 649C OKLD MN-PD CA
2021-08-05 510-951 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAYWARD CA
2021-03-04 510-916 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2021-02-25 510-973 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2020-12-22 510-971 0–9 XXXall 10 · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CA 7145 OKLD MN-PD CA
2020-12-11 510-831 0–9 XXXall 10 · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E RICHMOND CA
2020-12-10 510-641 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 ELSBR-PINL CA
2019-11-08 510-767 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
2019-10-16 510-630 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2019-09-27 510-216 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2019-07-26 510-994 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E RICHMOND CA
2019-06-10 510-980 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 FRNK MAIN CA
2019-05-28 510-807 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 HAYWARD CA
2019-04-17 510-961 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E FRNK GRNLF CA
2019-03-27 510-998 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 ELSBR-PINL CA
2019-03-21 510-988 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2019-03-19 510-977 0–9 XXXall 10 · 6 holders which blocks → FRACTEL, LLC 965H OKLD BKLY CA
2019-02-06 510-983 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E FRNK OLIVR CA
2019-01-22 510-975 0–9 XXXall 10 · 6 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD ALMD CA
2019-01-17 510-956 0–9 XXXall 10 · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E OKLD ALMD CA
2018-12-03 510-902 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - CA 649C FRNK MAIN CA
2018-12-03 510-954 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - CA 649C HAYWARD CA
2018-09-20 510-930 0–9 XXXall 10 · 4 holders which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F OKLD FRTVL CA
2018-09-17 510-905 0–9 XXXall 10 · 4 holders which blocks → METROPCS, INC. 5562 OKLD ALMD CA
2018-08-31 510-617 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - CA 649C HRCUL-RODE CA
2018-04-11 510-609 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 RICHMOND CA
2018-04-05 510-955 0–9 XXXall 10 · 6 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA 7240 OKLD TRNID CA
2018-03-16 510-607 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J OKLD MN-PD CA
2018-03-16 510-920 0–9 XXXall 10 · 4 holders which blocks → SONIC TELECOM, LLC - CA 433E OKLD MN-PD CA
2018-03-13 510-929 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E OKLD MN-PD CA
2018-02-20 510-603 0–9 XXXall 10 · 4 holders which blocks → COMCAST PHONE OF CALIFORNIA, LLC 394L OKLD FRTVL CA
2018-01-17 510-605 0–9 XXXall 10 · 7 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAYWARD CA
2017-12-21 510-650 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - CA 649C ELSBR-PINL CA
2017-12-18 510-616 0–9 XXXall 10 · 3 holders which blocks → SONIC TELECOM, LLC - CA 433E OKLD BKLY CA
2017-08-16 510-571 0–9 XXXall 10 · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 HAYWARD CA
2017-08-07 510-519 0–9 XXXall 10 · 3 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD ALMD CA
2017-04-14 510-561 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD FRTVL CA
2017-04-04 510-602 0–9 XXXall 10 · 3 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 FRNK MAIN CA
2016-12-12 510-941 0–9 XXXall 10 · 5 holders which blocks → COMCAST PHONE OF CALIFORNIA, LLC 394L FRNK GRNLF 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.