Area code 970

Area code 970 is a telephone area code in the North American Numbering Plan (NANP) for most of the western and northern parts of the U.S. state of Colorado. The numbering plan area includes Aspen, Breckenridge, Durango, Estes Park, Fort Collins, Glenwood Springs, Grand Junction, Greeley, Loveland, Silverthorne, Steamboat Springs, and Vail. It was established on April 2, 1995 in an area code split of area code 303, which was retained by the Denver area.

Ten-digit dialing
Area code 970 has PCS telephone numbers assigned for the central office code 988 in the Fort Collins exchange. As of October 17, 2020, 988 has been assigned by law as a three-digit code for the National Suicide Prevention Lifeline. To avoid conflicts in switching systems, the Federal Communications Commission ordered telecommunication carriers of 83 area codes, including 970, to transition to ten-digit dialing, even when the area code is not involved in an overlay complex. Per the timeline set by the North American Numbering Plan Administrator, permissive dialing began on April 24, 2021 and ten-digit dialing has been required from October 24, 2021.

Future overlay
In late 2025 or early 2026, area code 970 is expected to run out of available telephone numbers and an overlay is planned with area code 748.