NumberResearch Membership · Data 09/19/2026

Recent thousands-block assignments

13 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/19/2026

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

Most carrier growth happens here, not at the prefix level: under number pooling, carriers receive individual 1,000-number blocks (e.g. 626-470-0XXX) within already-assigned prefixes. Assignments are initial assignments — the current serving carrier of individual numbers may differ due to portability.

Most active assignees, last 30 days — NPA 831
ONVOY, LLC - CA 10
EXIANT COMMUNICATIONS LLC 2
BANDWIDTH.COM CLEC, LLC - CA 1
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 thousands-block assignments
AssignedThousands-blockLast 4 digitsStatusAssigneeOCNRate centerState
2006-09-13 831-585-3XXX 3000–3999Assigned METROPCS, INC. 5562 SALINAS CA
2006-09-12 831-383-8XXX 8000–8999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 MONTEREY CA
2006-09-12 831-383-9XXX 9000–9999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 MONTEREY CA
2006-09-08 831-737-3XXX 3000–3999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 SALINAS CA
2006-09-08 831-737-7XXX 7000–7999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 SALINAS CA
2006-09-08 831-737-8XXX 8000–8999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 SALINAS CA
2006-09-07 831-337-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOULDERCRK CA
2006-08-16 831-218-1XXX 1000–1999Assigned ONVOY, LLC - CA 649C BEN LOMOND CA
2006-08-16 831-515-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 SANTA CRUZ CA
2006-08-04 831-920-7XXX 7000–7999Assigned NEW CINGULAR WIRELESS PCS, LLC 6010 MONTEREY CA
2006-08-04 831-920-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC 6010 MONTEREY CA
2006-08-01 831-525-2XXX 2000–2999Assigned METROPCS, INC. 5562 KING CITY CA
2006-08-01 831-585-8XXX 8000–8999Assigned METROPCS, INC. 5562 SALINAS CA
2006-08-01 831-774-2XXX 2000–2999Assigned METROPCS, INC. 5562 GONZALES CA
2006-07-13 831-540-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 SALINAS CA
2006-06-22 831-824-5XXX 5000–5999Assigned LEVEL 3 COMMUNICATIONS, LLC - CA 8826 SANTA CRUZ CA
2006-06-12 831-515-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C SANTA CRUZ CA
2006-06-09 831-233-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 MONTEREY CA
2006-06-09 831-233-1XXX 1000–1999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 MONTEREY CA
2006-06-09 831-537-7XXX 7000–7999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HOLLISTER CA
2006-06-09 831-540-5XXX 5000–5999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 SALINAS CA
2006-06-09 831-540-8XXX 8000–8999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 SALINAS CA
2006-06-09 831-706-6XXX 6000–6999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 SANTA CRUZ CA
2006-06-09 831-706-7XXX 7000–7999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 SANTA CRUZ CA
2006-06-09 831-706-8XXX 8000–8999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 SANTA CRUZ CA
2006-06-02 831-222-4XXX 4000–4999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 FELTON CA
2006-06-02 831-223-2XXX 2000–2999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 SOLEDAD CA
2006-06-02 831-336-7XXX 7000–7999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 BEN LOMOND CA
2006-06-02 831-337-3XXX 3000–3999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 BOULDERCRK CA
2006-06-02 831-382-2XXX 2000–2999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 SAN LUCAS CA
2006-06-02 831-435-7XXX 7000–7999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 SANTA CRUZ CA
2006-06-02 831-613-5XXX 5000–5999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 GREENFIELD CA
2006-06-02 831-623-6XXX 6000–6999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 SAN JUAN CA
2006-06-02 831-627-5XXX 5000–5999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 SAN ARDO CA
2006-06-02 831-632-7XXX 7000–7999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 CASTROVL CA
2006-06-02 831-679-7XXX 7000–7999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 CHUALAR CA
2006-06-02 831-687-2XXX 2000–2999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 APTOS CA
2006-06-02 831-740-5XXX 5000–5999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 WATSONVL CA
2006-06-02 831-744-4XXX 4000–4999Assigned UTILITY TELECOM GROUP, LLC - CA 9262 GONZALES CA
2006-05-23 831-233-5XXX 5000–5999Assigned U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J MONTEREY CA
2006-05-18 831-484-3XXX 3000–3999Assigned METROPCS, INC. 5562 SALINAS CA
2006-05-17 831-274-5XXX 5000–5999Assigned LEVEL 3 COMMUNICATIONS, LLC - CA 8826 WATSONVL CA
2006-05-16 831-585-0XXX 0000–0999Assigned METROPCS, INC. 5562 SALINAS CA
2006-05-16 831-585-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 SALINAS CA
2006-05-16 831-794-8XXX 8000–8999Assigned METROPCS, INC. 5562 SALINAS CA
2006-05-16 831-794-9XXX 9000–9999Assigned METROPCS, INC. 5562 SALINAS CA
2006-05-16 831-869-5XXX 5000–5999Assigned METROPCS, INC. 5562 MONTEREY CA
2006-05-11 831-350-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - CA 8826 TRES PINOS CA
2006-05-09 831-435-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC 6010 SANTA CRUZ CA
2006-05-05 831-676-5XXX 5000–5999Assigned NEW CINGULAR WIRELESS PCS, LLC 6010 SALINAS CA

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.