California · Pacific Time
858 Area Code
The 858 area code is a telephone area code in California, covering San Diego and the surrounding area. It lies in the Pacific Time zone.
Last updated June 5, 2026
Where is the 858 area code?
858 serves San Diego and nearby communities in California. In the wider directory it sits in the West region.
Overlay codes serving San Diego
San Diego is served by an overlay of 2 area codes: 619, 858. Because more than one code covers the same area, 10-digit dialing is mandatory — you must dial the area code for every local call. New phone lines may be assigned any of these codes, so San Diego numbers are no longer tied to a single prefix.
History of the 858 area code
858 was introduced as an overlay to relieve number exhaustion in the San Diego area, adding capacity on top of 619 rather than splitting the region. Overlays let existing customers keep their numbers while new lines draw from the added code. Learn more in our overlay guide.
Is 858 a scam or spam risk?
858 is a legitimate geographic area code, not a premium or toll line, so a call from it costs you nothing extra. That said, scammers frequently spoof real local area codes to look familiar on caller ID. A genuine 858 number on your screen is no guarantee the caller is local or trustworthy. See spam & scam-risk area codes for how spoofing works and how to respond.
Other California area codes
Explore more
See every code in California, compare codes across the West region, or view all Pacific Time codes. You can also browse the 8XX block or the complete numeric list of US area codes.
New to how this all works? Start with how area codes work, then read up on overlays, 10-digit dialing, and spam & scam-risk codes. To check another number, use the area code lookup tool.
Quick answers
858 area code FAQ
Where is the 858 area code?
The 858 area code is in California, serving San Diego and the surrounding area in the West region.
What time zone is 858 in?
858 is in the Pacific Time zone.
Do I have to dial 10 digits for 858?
Yes. Because San Diego is an overlay area, you must dial the full 10-digit number (area code + 7 digits) for every call.
Is 858 a toll-free or premium code?
No. 858 is a standard geographic area code, so calling it costs the same as any local or long-distance call on your plan. Toll-free calls use 800, 888, 877, 866, 855, 844 or 833.