NumberResearchThousands-blocks in 657-363
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 657-363 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
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2015-08-21 | 657-363-0XXX | 0000–0999 | Assigned | IP HORIZON LLC | 515J | YORBALINDA | CA |
| 2015-06-19 | 657-363-1XXX | 1000–1999 | Assigned | COMCAST PHONE OF CALIFORNIA, LLC | 394L | YORBALINDA | CA |
| 2015-11-19 | 657-363-2XXX | 2000–2999 | Assigned | T-MOBILE USA, INC. | 6529 | YORBALINDA | CA |
| 2014-10-24 | 657-363-3XXX | 3000–3999 | Assigned | ONVOY, LLC - CA | 649C | YORBALINDA | CA |
| 2014-10-24 | 657-363-4XXX | 4000–4999 | Assigned | ONVOY, LLC - CA | 649C | YORBALINDA | CA |
| 2015-07-20 | 657-363-5XXX | 5000–5999 | Assigned | ONVOY, LLC - CA | 649C | YORBALINDA | CA |
| 2018-06-15 | 657-363-6XXX | 6000–6999 | Assigned | BANDWIDTH.COM CLEC, LLC - CA | 981E | YORBALINDA | CA |
| 2015-11-19 | 657-363-7XXX | 7000–7999 | Assigned | T-MOBILE USA, INC. | 6529 | YORBALINDA | CA |
| 2015-12-21 | 657-363-8XXX | 8000–8999 | Assigned | TWC IP ENABLED SERVICES, LLC | 793K | YORBALINDA | CA |
| 2014-10-17 | 657-363-9XXX | 9000–9999 | Assigned | T-MOBILE USA, INC. | 6529 | YORBALINDA | 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.