NumberResearchThousands-blocks in 408-580
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 408-580 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 408 blocks
Most active assignees, all time — NPA 408
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| — | 408-580-0XXX | 0000–0999 | Reserved | BANDWIDTH.COM CLEC, LLC - CA | 981E | SNJS SOUTH | CA |
| — | 408-580-1XXX | 1000–1999 | Reserved | T-MOBILE USA, INC. | 6529 | SNJS SOUTH | CA |
| — | 408-580-2XXX | 2000–2999 | Available | SNJS SOUTH | CA | ||
| 2019-12-02 | 408-580-3XXX | 3000–3999 | Assigned | PEERLESS NETWORK OF CALIFORNIA, LLC - CA | 373F | SNJS SOUTH | CA |
| 2003-10-20 | 408-580-4XXX | 4000–4999 | Assigned | T-MOBILE USA, INC. | 6529 | SNJS SOUTH | CA |
| — | 408-580-5XXX | 5000–5999 | Reserved | ONVOY, LLC - CA | 649C | SNJS SOUTH | CA |
| 2003-10-20 | 408-580-6XXX | 6000–6999 | Assigned | T-MOBILE USA, INC. | 6529 | SNJS SOUTH | CA |
| 2004-05-21 | 408-580-7XXX | 7000–7999 | Assigned | T-MOBILE USA, INC. | 6529 | SNJS SOUTH | CA |
| — | 408-580-8XXX | 8000–8999 | Reserved | ONVOY, LLC - CA | 649C | SNJS SOUTH | CA |
| 2020-03-03 | 408-580-9XXX | 9000–9999 | Assigned | PEERLESS NETWORK OF CALIFORNIA, LLC - CA | 373F | SNJS SOUTH | 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.