NumberResearchThousands-blocks in 928-357
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 928-357 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 928 blocks
Most active assignees, all time — NPA 928
New assignments by month
Sep 2026
Aug 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2026-01-14 | 928-357-0XXX | 0000–0999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | WINDOWROCK | AZ |
| — | 928-357-1XXX | 1000–1999 | Available | WINDOWROCK | AZ | ||
| — | 928-357-2XXX | 2000–2999 | Available | WINDOWROCK | AZ | ||
| — | 928-357-3XXX | 3000–3999 | Available | WINDOWROCK | AZ | ||
| 2026-04-28 | 928-357-4XXX | 4000–4999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - AZ | 3285 | WINDOWROCK | AZ |
| — | 928-357-5XXX | 5000–5999 | Available | WINDOWROCK | AZ | ||
| 2019-11-04 | 928-357-6XXX | 6000–6999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - AZ | 3285 | WINDOWROCK | AZ |
| — | 928-357-7XXX | 7000–7999 | Available | WINDOWROCK | AZ | ||
| — | 928-357-8XXX | 8000–8999 | Available | WINDOWROCK | AZ | ||
| — | 928-357-9XXX | 9000–9999 | Available | WINDOWROCK | AZ |
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.