Area code 720: where it is and who calls from it
Area code 720 is in Colorado.
Colorado (Denver, Boulder, Longmont, Aurora, Golden, Limon, Centennial; central Colorado)
| Where | Colorado |
|---|---|
| Time zone | Mountain Time ยท local time |
| In service since | 1998 |
| Overlay | Yes, with 303, 983 |
| Prefixes assigned | 785 of 792 possible (99%) |
Overlay: 720 covers the same area as 303, 983. Overlay areas use 10-digit dialing, so a seven-digit number alone won't connect, and neighbors can have different area codes.
Where 720 numbers started
Every prefix is assigned to a rate center, the local calling area it was set up in. These are the biggest in 720, with how many prefixes each has.
Who holds 720 numbers
- Mobile carrier 39%
- Local phone company 14%
- Internet / business phone carrier 44%
- Phone company 3%
| Carrier | Type | Prefixes | Share |
|---|---|---|---|
| T-Mobile (including Sprint) | Mobile carrier | 132 | 17% |
| CenturyLink / Lumen | Local phone company | 107 | 14% |
| AT&T Mobility | Mobile carrier | 92 | 12% |
| Verizon Wireless | Mobile carrier | 75 | 10% |
| Level 3 (Lumen) | Internet / business phone carrier | 63 | 8% |
| Onvoy | Internet / business phone carrier | 59 | 8% |
| Bandwidth | Internet / business phone carrier | 55 | 7% |
| MCImetro (Verizon Business) | Internet / business phone carrier | 51 | 6% |
| Teleport Communications America | Internet / business phone carrier | 31 | 4% |
| Comcast | Internet / business phone carrier | 21 | 3% |
Most prefixes are pooled: the 10,000 numbers in each are handed out in blocks of 1,000 to different carriers, and people can also take their numbers to another carrier. So the carrier shown is where the prefix started, not a guarantee about any one number.
States served: Colorado.
Other area codes in Colorado
Got a call from 720?
An area code tells you where a number was first assigned, not where the caller is. People keep their numbers when they move, and scammers can fake any number. If you weren't expecting the call, let it go to voicemail.
If the call shows a 720 number that matches the first six digits of your own, that's often neighbor spoofing. Use the box above to check the full number.
Area code facts from the NANPA area code database (updated 10/06/2026); prefixes and carriers from NANPA's central office code records (updated 2026-10-10). Place description adapted from Wikipedia, CC BY-SA 4.0.