Prefix 210-356 — San Antonio, TX

NANPA CO code assignment, current as of July 28, 2026.

The 210-356 prefix belongs to area code 210 and is anchored to the San Antonio rate center (TX). In NANP terms, the prefix — or NXX — determines the rate center a number is billed against.

San Antonio is part of the San Antonio-New Braunfels, TX Metropolitan Statistical Area. For routing purposes it sits in LATA 566. Numbers here keep Central time.

Code-holder of record: SOUTHWESTERN BELL (OCN 9533), assigned April 29, 2008. The prefix is pooled: its ten thousands-blocks can be shared among several carriers, so different 210-356 numbers may be served by different companies.

Caller ID showing 210-356 is not proof the call came from San Antonio: spoofing and porting both detach numbers from their origin. To verify a caller, hang up and dial the organization's published number, and report suspicious calls to the FTC.

Neighboring prefixes

FAQ

Where is 210-356 located?

The prefix is assigned to the San Antonio rate center in TX, area code 210. It is part of the San Antonio-New Braunfels, TX Metropolitan Statistical Area.

Which company owns 210-356 numbers?

SOUTHWESTERN BELL holds the code, but the prefix is pooled — individual thousands-blocks can be assigned to other carriers, and numbers may be ported to any provider.

Is a call from 210-356 safe to answer?

The prefix itself says nothing about the caller. Legitimate San Antonio businesses and spoofed robocalls can both display it. Never share personal data with an unverified inbound caller.