210
Area code

TX

United States geographic area code, in service since 1992-11-01. Part of the 210/726 overlay complex — ten-digit dialing required.

Split from 512. Created 830. Created 956. Created 726. Overlaid with 726 .

Statusin service
Introduced1992-11-01
JurisdictionTX, US
Local dialing10D
Time zoneCentral
Last verified2026-09-17
Utilization 101% of assignable prefixes assigned As of 09/17/2026
0%800 of ~792 assignable NXX values (200–999 excl. N11)100%

Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2001-01-29, most recent 2026-07-08.

Area codes serve rate-center geographies, not municipal boundaries. “TX” identifies the jurisdiction, not an exact city footprint.

Top assignees

Ranked by assigned prefixes · initial assignee ≠ current carrier
Largest initial assignees in area code 210
RankAssigneePrefixesShare
01 SOUTHWESTERN BELL 281 35.1%
02 NEW CINGULAR WIRELESS PCS, LLC - IL 129 16.1%
03 T-MOBILE USA, INC. 94 11.8%
04 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 54 6.8%
05 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 39 4.9%
06 ONVOY, LLC - TX 37 4.6%
07 LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 21 2.6%
08 BANDWIDTH.COM CLEC, LLC - TX 18 2.3%
09 LEVEL 3 COMMUNICATIONS, LLC - TX 16 2%
10 SPOK, INC. 13 1.6%

Important: these are initial assignees from NANPA CO-code records — the carrier a prefix was originally assigned to. Because of number portability, the current serving carrier of any individual number may differ.

Change history

Recorded events for this NPA

Planning letters & orders

Primary documents
NANPA planning letters for area code 210
DateDocumentSubject
2016-08-23 PL-495 ↗ NPA 726 to Overlay NPA 210 (Texas)
1997-01-22 PL-035 ↗ NANP-Split of 210 (Texas) Numbering Plan Area (NPA)
1992-03-01 IL-92-03-068 ↗ NANP-SPLIT OF 512 (SOUTH TEXAS) NUMBERING PLAN AREA (NPA)

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