Union City, California Area Code

Union City, CA is officially utilizing an area code overlay in which area codes 510 and 341 serve the same geographic area. Ten digit dialing (area code + seven digit number) is necessary.

In addition to Union City, CA area code information read more about area codes 510 and 341 details and California area codes.

Union City, CA is located in Alameda County and observes the Pacific Time Zone. View our Times by Area Code tool.