NumberResearch Membership · Data 09/20/2026

Thousands-blocks in 831-319

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 831-319 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 831 blocks

Most active assignees, all time — NPA 831
T-MOBILE USA, INC. 6
ONVOY, LLC - CA 1
NEW CINGULAR WIRELESS PCS, LLC 1
MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA 1
CHARTER IP ENABLED 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
— 831-319-0XXX 0000–0999Reserved MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA 7240 WATSONVL CA
2011-09-19 831-319-1XXX 1000–1999Assigned T-MOBILE USA, INC. 6529 WATSONVL CA
2012-07-13 831-319-2XXX 2000–2999Assigned T-MOBILE USA, INC. 6529 WATSONVL CA
2012-05-10 831-319-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 WATSONVL CA
2012-08-03 831-319-4XXX 4000–4999Assigned CHARTER IP ENABLED SERVICES, LLC 792K WATSONVL CA
2015-06-03 831-319-5XXX 5000–5999Assigned ONVOY, LLC - CA 649C WATSONVL CA
2014-10-14 831-319-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 WATSONVL CA
2013-12-04 831-319-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 WATSONVL CA
2011-07-21 831-319-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 WATSONVL CA
2015-09-03 831-319-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC 6010 WATSONVL 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.