West region · Mountain Time
Colorado Area Codes
All 6 area codes serving Colorado, the cities each one covers, and which are overlays. Colorado is served by 6 area codes in the Mountain Time zone.
Last updated October 1, 2026
Full list
Every Colorado area code
Colorado is served by 6 area codes in the Mountain Time zone. 3 of these are overlay codes layered over busy metros; the rest are geographic codes.
| Code | Area served | Type | In service |
|---|---|---|---|
| 303 | Denver, Boulder and the surrounding Front Range metro area in north-central Colorado | Geographic | Since 1947 |
| 719 | Southern and southeastern Colorado including Colorado Springs, Pueblo and the San Luis Valley | Geographic | Since 1988 |
| 720 | Denver, Boulder and the surrounding Front Range metro area in north-central Colorado | Overlay | Since 1998 |
| 748 | Northern and western Colorado including Fort Collins, Greeley, Grand Junction and the mountain resorts | Overlay | Since 2025 |
| 970 | Northern and western Colorado including Fort Collins, Greeley, Grand Junction and the mountain resorts | Geographic | Since 1995 |
| 983 | Denver, Boulder and the surrounding Front Range metro area in north-central Colorado | Overlay | Since 2022 |
Area codes and dialing in Colorado
Colorado's 6 area codes mix older geographic codes with newer overlays. The busiest metros — around Colorado Springs, Denver, Fort Collins — carry the most numbers and rely on overlays, which is why 10-digit dialing is required there. Quieter parts of the state may still use a single code. The original code in the Colorado list is 303 (Denver).
Whenever a Colorado region runs low on numbers, a new overlay is added on top rather than splitting the map, so existing customers keep their numbers. See 10-digit dialing for what that means in practice, or the newest area codes for upcoming changes.
Cities with multiple area codes
These Colorado metros are served by an overlay of two or more codes, so 10-digit dialing applies: Denver · Fort Collins.
Browse Colorado another way
Explore by West region, by time zone, or jump to the city index. You can also see the complete numeric list of every US area code.
Quick answers
Colorado area code FAQ
How many area codes does Colorado have?
Colorado currently has 6 area codes: 303, 719, 720, 748, 970, 983.
What is the main area code for Colorado?
The busiest metro in Colorado is served by the 303 code. Major cities include Colorado Springs, Denver, Fort Collins.
Does Colorado require 10-digit dialing?
Yes, in its overlay metros you must dial all 10 digits. Ten-digit dialing is the national standard.