San Leandro, CA is currently using one area code which is area code 510. Area code 510 was created from a split of area code 415 and put into service on September 2, 1991.
In addition to San Leandro, CA area code 510 serves much of the Eastern Bay area in Alameda County and the western portion of Contra Costa County in California including the larger cities and communities of Alameda, Berkeley, Castro Valley, El Cerrito, Fremont, Hayward, Newark, Oakland, Richmond, San Leandro, San Lorenzo, San Pablo, and Union City in addition to many smaller communities.
San Leandro, CA is located in Alameda County and observes the Pacific Time Zone. View our Times by Area Code tool.