| 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 |
|---|---|---|---|
| 303-226 | Denver | Denver | Landline |
| 303-357 | Denver | Denver | Landline |
| 303-678 | Longmont | Boulder | Landline |
| 303-874 | Littleton | Douglas | Landline |
| 303-777 | Denver | Denver | Landline |
| 303-771 | Denver | Denver | Landline |
| 303-269 | Denver | Denver | Landline |
| 303-517 | Denver | Denver | Wireless |
| 303-447 | Denver | Denver | Landline |
| 303-548 | Denver | Denver | Wireless |
| 303-720 | Fort Lupton | Weld | Wireless |
| 303-403 | Denver | Denver | Landline |
| 303-344 | Denver | Denver | Landline |
| 303-214 | Arvada | Jefferson | Landline |
| 303-488 | Denver | Denver | Landline |
| 303-575 | Denver | Denver | Landline |
| 303-477 | Denver | Denver | Landline |
| 303-736 | Denver | Denver | Landline |
| 303-382 | Denver | Denver | Landline |
| 303-409 | Denver | Denver | Landline |