Prefix 210-503 — San Antonio, TX

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

A phone number starting 210-503 was issued in the San Antonio rate center of TX — part of area code 210.

NANPA's central-office code records list AT&T ENTERPRISES, LLC (OCN 516C) as the code holder, assigned April 9, 2014. Because 210-503 participates in thousands-block pooling, individual 1,000-number blocks may belong to other carriers than the code holder.

A scammer can display 210-503 without ever touching TX. When in doubt, end the call and reach the company or agency through its official website; unwanted robocalls belong in the FTC's fraud report queue.

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.

Neighboring prefixes

FAQ

Where is 210-503 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 210-503 numbers?

AT&T ENTERPRISES, LLC 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 210-503 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.