The numbering plan area (NPA) includes most or all of the counties of San Luis Obispo, Santa Barbara, Ventura, and the southernmost portions of Monterey County.
In August 2016, the California Public Utilities Commission held a series of hearings for the decision of providing a relief area code in NPA 805 in the form of an overlay or an area code split.
[3][4] New telephone numbers of 820 area code began service in June 2018, requiring ten-digit dialing for all calls.
[5] In addition to the municipalities below, area code 805 also serves the US military facilities in Kwajalein, Republic of the Marshall Islands with a Paso Robles prefix (805-355).
This arrangement originated from the US Army's first satellite communications station having been built at nearby Camp Roberts.