NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

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

The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.

Most active assignees, all time — NPA 310
T-MOBILE USA, INC. 58
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 NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2024-02-14 310-757 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CMTN CMTN CA
2020-12-11 310-290 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 BEVERLYHLS CA
2017-01-16 310-554 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 CMTN CMTN CA
2012-10-02 310-307 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 W ANGELES CA
2006-11-07 310-310 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 SNMN SNMN CA
2005-08-30 310-982 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 SAN PEDRO CA
2005-05-10 310-703 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 INGLEWOOD CA
2005-02-22 310-561 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 TORRANCE CA
2005-02-14 310-987 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 SAN PEDRO CA
2005-01-03 310-986 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LOMITA CA
2004-11-08 310-654 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 INGLEWOOD CA
2002-10-17 310-985 6XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 SNMN SNMN CA
2002-09-06 310-430 7XXX which blocks → T-MOBILE USA, INC. 6529 SNMN SNMN CA
2002-08-21 310-951 not yet reported which blocks → T-MOBILE USA, INC. 6529 TORRANCE CA
2002-06-14 310-947 0XXX1XXX2XXX3XXX4XXX8XXX9XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 REDONDO CA
2002-02-22 310-462 none assigned yet which blocks → T-MOBILE USA, INC. 6529 INGLEWOOD CA
2002-02-21 310-980 not yet reported which blocks → T-MOBILE USA, INC. 6529 SNMN SNMN CA
2001-12-26 310-925 3XXX5XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 BEVERLYHLS CA
2001-10-18 310-920 not yet reported which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
2001-08-22 310-902 none assigned yet which blocks → T-MOBILE USA, INC. 6529 SNMN MRVS CA
2001-05-03 310-227 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 EL SEGUNDO CA
2001-02-28 310-936 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CULVERCITY CA
— 310-213 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-272 0–9 XXXall 10 · 9 holders which blocks → T-MOBILE USA, INC. 6529 BEVERLYHLS CA
— 310-345 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-346 2XXX which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-359 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 MALIBU CA
— 310-400 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-404 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-421 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 REDONDO CA
— 310-438 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 CMTN CMTN CA
— 310-493 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-497 none assigned yet which blocks → T-MOBILE USA, INC. 6529 BEVERLYHLS CA
— 310-505 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-590 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 INGLEWOOD CA
— 310-594 3XXX5XXX7XXX8XXX which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-619 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 TORRANCE CA
— 310-621 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CULVERCITY CA
— 310-628 none assigned yet which blocks → T-MOBILE USA, INC. 6529 SNMN SNMN CA
— 310-634 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 TORRANCE CA
— 310-678 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-684 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 SAN PEDRO CA
— 310-686 none assigned yet which blocks → T-MOBILE USA, INC. 6529 INGLEWOOD CA
— 310-704 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-709 none assigned yet which blocks → T-MOBILE USA, INC. 6529 W ANGELES CA
— 310-714 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-722 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CMTN GRDN CA
— 310-770 none assigned yet which blocks → T-MOBILE USA, INC. 6529 BEVERLYHLS CA
— 310-774 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 MALIBU CA
— 310-809 none assigned yet which blocks → T-MOBILE USA, INC. 6529 SAN PEDRO CA

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.