What area code is 303?
Here's everything about it.
Instant lookup for the 303 area code — location, time zone, cities served, and who's been calling from it. No sign-up, no app.
303 at a glance
Summary
Cities & regions served by 303
Denver7 communities on record for 303.
Where 303 sits on the map
Overlay: 720, 983Coverage area
About the 303 region
303 covers Denver in Colorado, including Boulder, Longmont, Aurora, Golden and Limon. The code has been in service since 1947 and is one of the original North American area codes.
As the Denver region grew, 303 ran low on available numbers, so 720 and 983 were added as overlay codes over the same geographic area. Both codes are local to each other and 10-digit dialing applies throughout.
Created for all of Colorado; 1988: split to create 719; 1995: split to create 970; 1998: overlaid by 720; 2022: overlaid by 983.
Who called me from 303?
Community reports- Caller ID is trivially spoofed: an incoming call that displays 303 does not prove the caller is really in the 303 region or even in the United States.
- Avoid calling back unknown one-ring numbers — some premium-rate scams rely on curiosity callbacks.
- Never share verification codes, payment details, or remote access during an unsolicited call, even if the caller claims to be your bank or a government agency.
- When a 303 call pressures you to act immediately, hang up and contact the organization directly through its official number.
Be the first to add a community report for a 303 number below.
Frequently asked questions
FAQWhat area code is 303?+–
303 is a telephone area code serving Denver in Colorado, United States, in service since 1947.
Where is area code 303 located?+–
It covers Boulder, Longmont, Aurora, Golden and Limon in Colorado.
What cities are in area code 303?+–
Major communities on record include Boulder, Longmont, Aurora, Golden and Limon, among others. The code's territory spans the Denver region of Colorado.
What time zone is 303?+–
303 observes Mountain (MT), which is UTC−7 / −6 DST and follows daylight saving time.
When did area code 303 start?+–
303 entered service in 1947 as one of the original 1947 North American area codes. Its history: created for all of Colorado; 1988: split to create 719; 1995: split to create 970; 1998: overlaid by 720; 2022: overlaid by 983.
Why do calls to 303 require 10-digit dialing?+–
303 shares its territory with overlay code 720 and 983. Because both codes serve the same geographic area, the phone network needs all 10 digits to route a call, and calls between the codes are still local.
Is 303 a scam area code?+–
Scam and robocall traffic can use any North American code, 303 included — caller ID is easy to spoof, so the code alone does not tell you who is really calling. Check the community reports on this page before calling back an unknown 303 number, and report anything suspicious.
Can I get a 303 phone number?+–
Yes — most mobile carriers and VoIP providers let you request a 303 number regardless of where you physically live.