NumberResearch Membership · Data 09/20/2026

Thousands-blocks in 310-957

This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/20/2026

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

The ten 1,000-number thousand-blocks inside prefix 310-957 and who was initially assigned each. Under pooling these blocks often belong to different carriers — the single prefix-level “assignee” is usually just the pool / code holder, not who holds the numbers. ← all 310 blocks

Most active assignees, all time — NPA 310
BANDWIDTH.COM CLEC, LLC - CA 3
METROPCS NETWORKS, LLC 2
MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA 2
T-MOBILE USA, INC. 1
MCIMETRO ACCESS TRANSMISSION SERVICES LLC 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
2004-01-15 310-957-0XXX 0000–0999Assigned METROPCS NETWORKS, LLC 899D INGLEWOOD CA
2013-02-20 310-957-1XXX 1000–1999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 INGLEWOOD CA
2010-05-26 310-957-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 INGLEWOOD CA
— 310-957-3XXX 3000–3999Reserved MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA 7240 INGLEWOOD CA
2013-12-04 310-957-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 INGLEWOOD CA
2013-04-25 310-957-5XXX 5000–5999Assigned BANDWIDTH.COM CLEC, LLC - CA 981E INGLEWOOD CA
— 310-957-6XXX 6000–6999Reserved MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA 7240 INGLEWOOD CA
2004-01-15 310-957-7XXX 7000–7999Assigned METROPCS NETWORKS, LLC 899D INGLEWOOD CA
2012-08-24 310-957-8XXX 8000–8999Assigned BANDWIDTH.COM CLEC, LLC - CA 981E INGLEWOOD CA
2010-09-16 310-957-9XXX 9000–9999Assigned BANDWIDTH.COM CLEC, LLC - CA 981E INGLEWOOD CA

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.