NumberResearchThousands-blocks in 310-818
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/21/2026
The ten 1,000-number thousand-blocks inside prefix 310-818 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
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2024-03-25 | 310-818-0XXX | 0000–0999 | Assigned | TERRA NOVA TELECOM INC. | 145J | CMTN GRDN | CA |
| 2003-09-04 | 310-818-1XXX | 1000–1999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | CMTN GRDN | CA |
| — | 310-818-2XXX | 2000–2999 | Reserved | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | CMTN GRDN | CA |
| 2010-07-16 | 310-818-3XXX | 3000–3999 | Assigned | BANDWIDTH.COM CLEC, LLC - CA | 981E | CMTN GRDN | CA |
| 2003-09-19 | 310-818-4XXX | 4000–4999 | Assigned | IP HORIZON LLC | 515J | CMTN GRDN | CA |
| 2005-05-03 | 310-818-5XXX | 5000–5999 | Assigned | PAETEC ITEL, LLC | 829J | CMTN GRDN | CA |
| 2006-05-31 | 310-818-6XXX | 6000–6999 | Assigned | T-MOBILE USA, INC. | 6529 | CMTN GRDN | CA |
| 2004-12-10 | 310-818-7XXX | 7000–7999 | Assigned | ONVOY, LLC - CA | 649C | CMTN GRDN | CA |
| 2024-09-17 | 310-818-8XXX | 8000–8999 | Assigned | ONVOY SPECTRUM, LLC | 624H | CMTN GRDN | CA |
| 2006-05-31 | 310-818-9XXX | 9000–9999 | Assigned | T-MOBILE USA, INC. | 6529 | CMTN GRDN | CA |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/21/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.