510 Area Code – Oakland, California: Location, Time Zone & History

Oakland and the rest of the East Bay have carried area code 510 since September 2, 1991, when it split off from San Francisco's original 415 numbering plan. The new territory covered Alameda and Contra Costa Counties, taking in Oakland, Berkeley, Fremont, Hayward, Alameda, and San Leandro along with smaller cities like Emeryville, Piedmont, and Albany.

Seven years later, in 1998, the inland East Bay was split off as area code 925, with the Berkeley Hills serving as the dividing line between the two regions. Growth continued regardless: in 2019, area code 341 was introduced as an all-services overlay on 510, with mandatory ten-digit dialing beginning a month ahead of it.

The East Bay economy served by 510/341 reflects its position at the edge of the San Francisco Bay. The Port of Oakland is one of the busiest container ports in the country, supporting a base of port and maritime logistics alongside technology, biotechnology, and life sciences firms. Berkeley, home to the University of California, Berkeley, anchors the region's higher education and research presence, while Oakland remains Alameda County's largest city and the East Bay's principal urban center.