| General Information about Area Code 303 | |
|---|---|
| Country | United States |
| State / Province / Territory | Colorado |
| Major City | Denver |
| Time Zone | Mountain (UTC-07:00) |
| Prefix | Primary City | County | Phone Type |
|---|---|---|---|
| 303-819 | Denver | Denver | Wireless |
| 303-709 | Longmont | Boulder | Wireless |
| 303-778 | Denver | Denver | Landline |
| 303-982 | Golden | Jefferson | Landline |
| 303-856 | Littleton | Douglas | Landline |
| 303-612 | Denver | Denver | Wireless |
| 303-439 | Denver | Adams | Landline |
| 303-464 | Denver | Adams | Landline |
| 303-287 | Denver | Denver | Landline |
| 303-444 | Denver | Denver | Landline |
| 303-791 | Littleton | Arapahoe | Landline |
| 303-852 | Denver | Denver | Wireless |
| 303-876 | Denver | Denver | Landline |
| 303-599 | Denver | Denver | Wireless |
| 303-908 | Denver | Denver | Wireless |
| 303-919 | Denver | Denver | Wireless |
| 303-296 | Denver | Denver | Landline |
| 303-834 | Longmont | Boulder | Wireless |
| 303-751 | Denver | Denver | Landline |
| 303-715 | Denver | Denver | Landline |