Area Code 303 at a Glance
| Area code | 303 |
| Region | Colorado |
| Country | United States |
| Primary timezone | America/Denver |
| Dialing format | +1 (303) NXX-XXXX |
Cities and Places Using Area Code 303
Based on prefix-level carrier data, area code 303 covers places including:
- Denver, CO
- Aurora, CO
- Littleton, CO
- Boulder, CO
- Golden, CO
- Longmont, CO
- Broomfield, CO
- Lakewood, CO
- Englewood, CO
- Brighton, CO
- Highlands Ranch, CO
- Castle Rock, CO
Frequently Asked Questions
Where is area code 303?
Area code 303 serves Colorado, United States.
Who is calling me from area code 303?
A call from area code 303 most likely originates from Colorado, but caller ID can be spoofed. If an unknown caller asks for personal or payment information, hang up and call the organization back on its official number.
How do I dial a 303 number?
Within North America: dial 1-303 followed by the 7-digit number. From abroad: your international prefix (like 00 or +), then 1 303 and the number.