NumberResearchThousands-blocks in 310-683
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
The ten 1,000-number thousand-blocks inside prefix 310-683 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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Dec 2025
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2005-04-01 | 310-683-0XXX | 0000–0999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | REDONDO | CA |
| 2004-01-15 | 310-683-1XXX | 1000–1999 | Assigned | PAETEC COMMUNICATIONS, INC. - CA | 4733 | REDONDO | CA |
| 2005-04-01 | 310-683-2XXX | 2000–2999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | REDONDO | CA |
| 2004-04-13 | 310-683-3XXX | 3000–3999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | 6006 | REDONDO | CA |
| 2005-01-11 | 310-683-4XXX | 4000–4999 | Assigned | TWILIO INTERNATIONAL, INC. | 506J | REDONDO | CA |
| 2005-01-11 | 310-683-5XXX | 5000–5999 | Assigned | IP HORIZON LLC | 515J | REDONDO | CA |
| — | 310-683-6XXX | 6000–6999 | Reserved | TELEPORT COMMUNICATIONS AMERICA, LLC - CA | 7139 | REDONDO | CA |
| 2024-01-26 | 310-683-7XXX | 7000–7999 | Assigned | ONVOY, LLC - CA | 649C | REDONDO | CA |
| 2004-07-19 | 310-683-8XXX | 8000–8999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | 6006 | REDONDO | CA |
| 2004-07-19 | 310-683-9XXX | 9000–9999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | 6006 | REDONDO | 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.