Alamosa Credit Union was originally chartered on March 27, 1945 under the name of Alamosa Hispanic Credit Union. The field of membership at that time was limited to people of Hispanic Background and others related to a person of Hispanic background through marriage within the county of Alamosa.

In May of 1982 the Alamosa City and County Credit Union merged with the Alamosa Hispanic Credit Union changing the field of membership to include city and county employees of Alamosa. June of 1984 Sacred Heart Parish Credit Union merged with the Alamosa Hispanic Credit Union and the name was officially changed to the Alamosa Credit Union opening up the field of membership to anyone working or living in Alamosa County and their immediate family members.

Friendship Credit Union merged with the Alamosa Credit Union in January of 1989, no changes to the field of membership.

May of 2006 the San Juan Community Credit Union merged with the Alamosa Credit Union opening the field of membership to include anyone living or working in Alamosa or Rio Grande Counties and their immediate family members.