NumberResearch Membership · Data 09/19/2026

Thousands-blocks in 509-303

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

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The ten 1,000-number thousand-blocks inside prefix 509-303 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 509 blocks

Most active assignees, all time — NPA 509
T-MOBILE USA, INC. 4
METROPCS, INC. 2
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WA 2
ONVOY, LLC - WA 1
CENTURYLINK COMMUNICATIONS, LLC 1
New assignments by month Sep 2026 Aug 2026 Jul 2026 Jun 2026 May 2026 Apr 2026 Mar 2026 Feb 2026 Jan 2026 Dec 2025 Nov 2025 Oct 2025
Clear Download CSV ↓
Recent thousands-block assignments
AssignedThousands-blockLast 4 digitsStatusAssigneeOCNRate centerState
— 509-303-0XXX 0000–0999Reserved T-MOBILE USA, INC. 6529 PROSSER WA
2011-10-25 509-303-1XXX 1000–1999Assigned T-MOBILE USA, INC. 6529 PROSSER WA
2019-07-01 509-303-2XXX 2000–2999Assigned METROPCS, INC. 5562 PROSSER WA
2019-04-26 509-303-3XXX 3000–3999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WA 5812 PROSSER WA
2016-03-08 509-303-4XXX 4000–4999Assigned ONVOY, LLC - WA 483E PROSSER WA
2020-11-06 509-303-5XXX 5000–5999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WA 5812 PROSSER WA
2022-04-18 509-303-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 PROSSER WA
2014-12-23 509-303-7XXX 7000–7999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J PROSSER WA
2006-01-03 509-303-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 PROSSER WA
— 509-303-9XXX 9000–9999Reserved METROPCS, INC. 5562 PROSSER WA

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.