Ontario, California Area Code

Ontario, CA Area Codes are

909 and 840

Ontario, CA is officially utilizing an area code overlay in which area codes 909 and 840 serve the same geographic area. Ten digit dialing (area code + seven digit number) is necessary.

In addition to Ontario, CA area code information read more about area code 909 and 840 details and California area codes.

Ontario, CA is located in San Bernardino County and observes the Pacific Time Zone. View our Times by Area Code tool.

California Area Code Map