6 area codes assigned to Colorado · Mountain Time
2 of Colorado's area codes share territory with another. Codes in the same row serve the same places, so either can reach a number there — and ten-digit dialling is required throughout.
The remaining 2 codes cover their own area: 719, 983.
Colorado went from one area code in 1947 to 6 today. A split carves territory off its parent; an overlay sits on top of it, which is why newer codes need ten-digit dialling.
Dates from the NANPA area code report, 09/19/2026.
Colorado spans 7 LATAs — the regions a call is routed within before it becomes long-haul.
303
Colorado
Mountain Time
Overlay · with 720
3,058 blocks · 13 rate centres
719
Colorado
Mountain Time
4,747 blocks · 83 rate centres
720
Colorado
Mountain Time
Overlay · with 303
7,286 blocks · 12 rate centres
748
Colorado
Mountain Time
Overlay · Jul 7, 2025 · with 970
0 blocks · 0 rate centres
970
Colorado
Mountain Time
Overlay · with 748
5,530 blocks · 119 rate centres
983
Colorado
Mountain Time
406 blocks · 6 rate centres
Colorado has more than one area code in most regions. Enter a city to see which codes serve it, or check a specific number instead.
Colorado has had 4 area codes activated as an overlay since 2021, sharing territory with an existing code rather than carving out new geography. Local calls in an overlaid region must be dialed with all ten digits. Earlier overlays are not listed here.
Colorado is served by 6 area codes in the North American Numbering Plan (NANP): 303, 719, 720, 748, 970, 983. All Colorado numbers are in the Mountain Time zone. Click any area code above to see the cities and rate centers it covers, formatted tel: link examples, and to search for available phone numbers.