🇺🇸 United States · Colorado

Area code 303

Area code 303 is a telephone area code in Colorado, United States, covering Denver, Aurora, Littleton, Boulder, Golden, Longmont and more. Local time is UTC−7 (UTC−6 in summer). Numbers look like (303) 234-5678, or +1 303 234 5678 from abroad.

State: Colorado
Time zone: Denver UTC−7 (UTC−6 in summer)
Local time now: –
Dial from abroad: +1 303

Places in area code 303

Cities and towns with telephone exchanges in the 303 area code, most exchanges first.

Denver
Aurora
Littleton
Boulder
Golden
Longmont
Broomfield
Lakewood
Englewood
Highlands Ranch
Brighton
Castle Rock
Evergreen
Parker
Nederland
Arvada
Hudson
Idaho Springs
Georgetown
Black Hawk
Kiowa
Strasburg
Bennett
Elizabeth

How to dial area code 303

Calling from	You dial
Inside the 303 area	303 234 5678 (10 digits)
Elsewhere in the US & Canada	1 303 234 5678
Any mobile phone, anywhere	+1 303 234 5678
UK, Europe, India and most countries	00 1 303 234 5678
Australia	0011 1 303 234 5678

Other area codes in Colorado

719 Colorado Springs, Pueblo 720 Denver, Aurora 748 Colorado 970 Fort Collins, Greeley 983 Colorado

Area code 303: FAQ

Where is area code 303?

Area code 303 is in Colorado, United States and serves Denver, Aurora, Littleton, Boulder, Golden, Longmont. and other places

What time zone is area code 303 in?

Area code 303 is in the America/Denver time zone (UTC−7 (UTC−6 in summer)).

How do I call a 303 number from outside the US and Canada?

Dial your exit code (00 in most countries, or + on a mobile), then 1, then 303 and the seven-digit number. Example: +1 303 234 5678.

Is a call from area code 303 a scam?

Area code 303 is a regular North American area code, but caller ID can be spoofed: scammers often show local-looking numbers. Do not call back unknown numbers that ask for money or personal data, and check the number with the phone number validator to see whether it is valid and whether it is a mobile, landline or VoIP number.

Phone number API

Check 303 numbers in your app

numlookupapi checks any phone number worldwide in one request and returns validity, line type, carrier, location and every standard format as JSON.

Read the documentation

100 free requests every month. No credit card required.

GET https://api.numlookupapi.com/v1/validate/+13032345678

{
  "valid": true,
  "number": "12069220880",
  "local_format": "2069220880",
  "international_format": "+12069220880",
  "country_prefix": "+1",
  "country_code": "US",
  "country_name": "United States of America",
  "location": "Seattle",
  "line_type": "landline",
  "e164_format": "+12069220880",
  "national_format": "(206) 922-0880"
}