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AREA CODE · COLORADO

Area code 303

Area code 303 covers Denver, Colorado. Map, time zone, overlays, carriers, the full list of prefixes and how to dial it.

State: Colorado Major City: Denver Mountain Time (MT) Overlay: 303/720/983
01 / WHERE IT IS

Where is area code 303?

Area code 303 is assigned to Denver and the surrounding region in Colorado. Calls to numbers that start with 303 are routed to this area.

Area code 303 shares its territory with 720, 983. Because it is an overlay, local calls require dialing all 10 digits.

Counties covered

Denver CountyBoulder CountyWeld County

Line types

  • Mobile 23.18%
  • Landline 76.82%
02 / MAP

Area code 303 on the map

The shaded area joins the code’s numbering centers; the marker shows its main city.

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© OpenStreetMap contributors

03 / LOCAL TIME

Current time in Denver

This area code is in the Mountain Time (MT) time zone.

Local timeDenver, CO--:--:--

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America/DenverLive
04 / HOW TO DIAL

How to call Denver

WITHIN THE US303 XXX XXXX

Always 10 digits — landline, mobile or VoIP. Local, long distance or a different state: the format is always the same. You do not need to dial the 1 first.

FROM ABROAD+1 303 XXX XXXX

Exit codes: 00 Europe/Mexico · 011 Canada · 010 Japan · + universal

WHATSAPP / IMESSAGE+1 303 XXX XXXX

Always save the number in international format so messaging apps recognize it correctly:

Call typeTraditional landlineMobile / VoIP
Local (same area code)10 digits10 digits
US long distance1 + 10 digits10 digits
Emergency911911
🌐Universal+1 303 555 0123
🇪🇸🇲🇽Spain / Mexico00 1 303 555 0123
🇦🇺Australia0011 1 303 555 0123
🇯🇵Japan010 1 303 555 0123
HAVE THE FULL NUMBER?

Learn more about that number.

Check the line type and the carrier the number block was originally assigned to.

10 digits to see the carrier and line type of the number

05 / CARRIERS

Carriers in area code 303

Share of the number blocks by carrier and line type.

Landline

Lumen Technologies
84%
Verizon Business
5%
AT&T
5%
Sinch
2%
Comcast
1%
Others
2%

Mobile

Verizon Wireless
33%
USA Mobility
23%
T-MOBILE USA
21%
AT&T Mobility
19%
Sinch
1%
Others
2%

Carrier shown is the original assignment of each number block and may differ today because of number portability.

06 / PREFIXES

Complete list of prefixes for area code 303

785 number blocks (NXX) assigned in this area code.

PrefixTypeCityCarrier
(303) 200 Landline Denver AT&TTELEPORT COMMUNICATIONS AMERICA, LLC - CO
(303) 201 Mobile Denver USA MobilityUSA MOBILITY WIRELESS, INC.
(303) 202 Landline Denver Lumen TechnologiesQWEST CORPORATION
(303) 203 Mobile Denver USA MobilityAMERICAN MESSAGING SERVICES, LLC
(303) 204 Mobile Denver Verizon WirelessCELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO
(303) 205 Landline Denver Lumen TechnologiesQWEST CORPORATION
(303) 206 Mobile Denver USA MobilityUSA MOBILITY WIRELESS, INC.
(303) 207 Mobile Denver USA MobilityUSA MOBILITY WIRELESS, INC.
(303) 208 Mobile Denver USA MobilityUSA MOBILITY WIRELESS, INC.
(303) 209 Landline Denver Verizon BusinessMCIMETRO ACCESS TRANSMISSION SERVICES LLC

Showing 10 of 785 prefixes

07 / FAQ

Frequently asked questions about area code 303

Where is area code 303 used?
Area code 303 serves Denver and the surrounding area in Colorado, including Denver County, Boulder County, Weld County.
What city is area code 303 from?
The main city of area code 303 is Denver, CO.
What time zone is area code 303 in?
Area code 303 is in the Mountain Time (MT) time zone (America/Denver).
Is 303 an overlay area code?
Yes. It shares its territory with 720, 983. In an overlay, every call requires dialing all 10 digits.
How do I call a number with area code 303 from the United States?
Dial the 10 digits: 303 + 7-digit number. For some long-distance calls from a landline you may need to add a 1 first.
How do I call a 303 number from another country?
Dial your country's exit code (or +), then 1, then 303 and the seven-digit number. From a mobile you can use +1 303 XXX XXXX.
Which carriers use area code 303?
Most landline blocks belong to Lumen Technologies and most mobile blocks to Verizon Wireless. The carrier shown is the original assignment and may differ today because of number portability.
Is area code 303 for landlines, mobiles or both?
Both. About 76.82% of the number blocks are landline, 23.18% mobile.
How do I save a 303 number in WhatsApp or my phone?
Save it in international format: +1 303 XXX XXXX. That way WhatsApp, iMessage and Telegram recognize it from any country.
Is it safe to answer calls from area code 303?
The area code only shows the region a number was assigned to; it does not tell you who is calling. Scammers can fake any area code, so do not share personal or banking information with unknown callers, and let unknown numbers go to voicemail.
KEEP EXPLORING

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Other area codes in Colorado

719 · Colorado Springs-Main720 · Denver970 · Fort Collins983 · Denver

View all Colorado area codes →