Prefix 303-515 — Denver, CO

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

Area code
303
Prefix (NXX)
515
Rate center
Denver
State
Colorado
Time zone
Mountain
Code holder
ONVOY, LLC - CO
OCN
026D
Pooled
Yes (thousands-block pooling)
Assigned
2011-11-14
LATA
656

The 303-515 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.

The assigned code holder is ONVOY, LLC - CO, operating company number 026D, assigned November 14, 2011. This is a pooled prefix — expect numbers within it to be split across more than one carrier in 1,000-number blocks.

Caller ID showing 303-515 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

Prefixes adjacent to 303-515
PrefixRate centerCode holder
303-512 Denver QWEST CORPORATION
303-513 Denver NEW CINGULAR WIRELESS PCS, LLC
303-514 Denver CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO
303-516 Denver QWEST CORPORATION
303-517 Denver NEW CINGULAR WIRELESS PCS, LLC
303-518 Denver CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO

FAQ

Where is 303-515 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 303-515 numbers?

ONVOY, LLC - CO 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 303-515 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.