California · Pacific Time
858 Area Code
Area code 858 is in California, serving San Diego and southern and eastern San Diego County. It is in the Pacific Time zone. It shares its territory with overlay code 619, so 10-digit dialing is required.
Last updated October 1, 2026 · Source: NANPA
Where is the 858 area code?
858 is a California area code covering San Diego and southern and eastern San Diego County. In the wider directory it sits in the West region.
Cities in the 858 area code
- San Diego
- Chula Vista
- El Cajon
- La Mesa
- National City
- Santee
- Lemon Grove
- Poway
- Coronado
- Imperial Beach
- Spring Valley
Counties served by 858
San Diego County.
858 overlay codes and dialing
The 858 territory is covered by an overlay of 2 area codes: 619, 858. All of them serve the same geographic area, and the original code is 619. Because more than one code covers the same ground, 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.
History of the 858 area code
858 went into service on June 12, 1999 as an overlay of 619, relieving number exhaustion in the San Diego area. Rather than splitting the region, the overlay lets 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 in San Diego, CA 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, covering San Diego and southern and eastern San Diego County, in the West region.
What cities are in the 858 area code?
Cities in the 858 area code include San Diego, Chula Vista, El Cajon, La Mesa, National City, Santee, Lemon Grove, Poway, Coronado and Imperial Beach.
What time zone is 858 in?
858 is in the Pacific Time zone.
What is the overlay for the 858 area code?
858 shares its territory with 619. Both codes (619, 858) serve the same area, so 10-digit dialing is required for every call.
When did the 858 area code start?
858 went into service on June 12, 1999 as an overlay of 619.
Do I have to dial 10 digits for 858?
Yes. Because 858 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.