Area code · CO
303 area code
The 303 area code serves Denver, Colorado. Look up a specific 303 number, or browse other popular area codes.
2 min readUpdated October 6, 2026By the SecondBars team
Location
Denver, CO
Timezone
Mountain
State
Colorado
Major cities
Denver, Boulder, Aurora
ABOUTAbout the 303 area code
The 303 area code is assigned to Denver, Colorado. Phone numbers with this area code are used by residents and businesses in the Denver metropolitan area and surrounding communities.
If you've received an unwanted call from a 303 area code number, use the phone lookup to see what we have on file for it. Don't call back numbers you don't recognize or share personal details, and block numbers that keep calling.
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