California Search & Rescue (formerly California Explorer Search & Rescue or Cal-ESAR) grew from the Explorer Program of the Boy Scouts of America (Post 12 chartered in 1969). CALSAR has since evolved into it's own separate search and rescue organization, fully self-funded and independently run.

In the Explorer days, Post 12 became the first certified Explorer Search & Rescue unit in California, and in 1974 began responding to rescue missions and performed other public service activities. In 1986, Post 12 became the first Explorer Search & Rescue unit under the California Office of Emergency Services serving a statewide area of response.