The area code 858 is located in San Diego, California.
Area code 858 serves the northern and coastal parts of San Diego County, California, including key neighborhoods within the City of San Diego. Centered north of downtown, it stretches along the I‑5 and I‑15 corridors and covers a major hub for tech, biotech, and research anchored by UC San Diego and the Torrey Pines area. The code was introduced in 1999 as a split from 619 to support the region’s fast growth in phone numbers. It operates on Pacific Time and is widely used for both residential and business lines across this thriving coastal region.
Major communities and landmarks in 858 include:
Area code 858 stands out for its mix of coastal beauty and innovation, with research labs, startups, and established firms sharing space near sea cliffs and canyons. Landmarks like Torrey Pines Golf Course—host to multiple U.S. Opens—and the Birch Aquarium add to its recognition beyond the region. Neighboring codes include 619 to the south and 760/442 to the north and east, making 858 a clear marker for North and coastal San Diego calls. Expect strong ties to higher education, science, and outdoor life, all reflected in everyday 858 phone numbers.
"Year established: 1999" — Source: NANPA (North American Numbering Plan Administration)