Prefix 303-317 — Denver, CO

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

The 303-317 prefix belongs to area code 303 and is anchored to the Denver rate center (CO). In NANP terms, the prefix — or NXX — determines the rate center a number is billed against.

Denver is part of the Denver-Aurora-Centennial, CO Metropolitan Statistical Area. For routing purposes it sits in LATA 656. Numbers here keep Mountain time.

NANPA's central-office code records list QWEST CORPORATION (OCN 9636) as the code holder. Because 303-317 participates in thousands-block pooling, individual 1,000-number blocks may belong to other carriers than the code holder.

Caller ID showing 303-317 is not proof the call came from Denver: 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 303-317 located?

The prefix is assigned to the Denver rate center in CO, area code 303. It is part of the Denver-Aurora-Centennial, CO Metropolitan Statistical Area.

Which company owns 303-317 numbers?

QWEST CORPORATION 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 303-317 safe to answer?

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