NumberResearchThousands-blocks in 657-357
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/19/2026
The ten 1,000-number thousand-blocks inside prefix 657-357 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 657 blocks
Most active assignees, all time — NPA 657
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2019-02-19 | 657-357-0XXX | 0000–0999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - CA | 7139 | SANTA ANA | CA |
| 2018-08-28 | 657-357-1XXX | 1000–1999 | Assigned | METROPCS NETWORKS, LLC | 899D | SANTA ANA | CA |
| 2019-01-17 | 657-357-2XXX | 2000–2999 | Assigned | T-MOBILE USA, INC. | 6529 | SANTA ANA | CA |
| 2019-01-31 | 657-357-3XXX | 3000–3999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | SANTA ANA | CA |
| 2018-10-04 | 657-357-4XXX | 4000–4999 | Assigned | T-MOBILE USA, INC. | 6529 | SANTA ANA | CA |
| 2018-10-04 | 657-357-5XXX | 5000–5999 | Assigned | T-MOBILE USA, INC. | 6529 | SANTA ANA | CA |
| 2018-10-02 | 657-357-6XXX | 6000–6999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | SANTA ANA | CA |
| 2018-10-02 | 657-357-7XXX | 7000–7999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | SANTA ANA | CA |
| 2018-08-28 | 657-357-8XXX | 8000–8999 | Assigned | METROPCS NETWORKS, LLC | 899D | SANTA ANA | CA |
| 2018-08-28 | 657-357-9XXX | 9000–9999 | Assigned | METROPCS NETWORKS, LLC | 899D | SANTA ANA | CA |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.