NANP area code
858
UTC−8, UTC−7 during daylight saving
- State
- California
- Primary city
- San Diego
- Time zone
- Pacific
- In service
- 1999
- Overlay
- 619
NANP area code
858
UTC−8, UTC−7 during daylight saving
The code reaches 32 communities and 1 county across California.
The area code itself carries no risk signal. 858 is assigned to San Diego, California, so a call from it is consistent with a real caller in that area — but the digits alone prove nothing, because they can be forged.
Caller ID is set by whoever places the call, not verified by the network. That is why neighbour spoofing works: an operation anywhere in the world can display a number that matches the area code — and often the first three digits after it — of the person being called, so the call looks local. Every community in the 858 territory is a plausible-looking origin for a forged 858 number, which is why one can be made to look like a neighbour to so many people. The same applies to its overlay code 619, which serves the same ground.
If you did not recognise the call: let it go to voicemail — a legitimate caller with real business will leave one. Do not return the call using the number shown; look the organisation up independently and call the number you found. Never confirm personal details, card numbers, or one-time codes to someone who called you, however plausible the number looked.
Codes.zone publishes no complaint counts, risk scores, or caller identities. We hold no data on individual numbers and will not estimate what we cannot source.
Time there now
—
Pacific · UTC−8, UTC−7 during daylight saving
Reasonable callback window
8:00 AM – 9:00 PM
local time in Pacific
Federal rules bar telemarketing calls to a residence outside 8:00 AM–9:00 PM in the called party's own time zone. It is a sensible bound for a personal callback too — and a caller who rang you well outside it was not observing it.
858 does not have its territory to itself. 619 covers the same ground, serving San Diego and the rest of the 858 territory. An overlay is what a regulator adds when a region runs out of assignable numbers: rather than splitting the area and forcing half the residents to change their number, a second code is laid over the top and new numbers are issued from it.
The practical consequence: two neighbours on the same street can hold numbers in different area codes, so the code tells you nothing about which part of town a caller is in — and local calls must be dialled as all ten digits, because seven is no longer unambiguous.
| City | ZIP codes | County |
|---|---|---|
| San Diego | 76 | San Diego County |
| Chula Vista | 8 | San Diego County |
| La Jolla | 5 | San Diego County |
| El Cajon | 4 | San Diego County |
| La Mesa | 4 | San Diego County |
| Spring Valley | 4 | San Diego County |
| Alpine | 2 | San Diego County |
| Bonita | 2 | San Diego County |
| Coronado | 2 | San Diego County |
| Encinitas | 2 | San Diego County |
| Imperial Beach | 2 | San Diego County |
| Lemon Grove | 2 | San Diego County |
| National City | 2 | San Diego County |
| Poway | 2 | San Diego County |
| Rancho Santa Fe | 2 | San Diego County |
| San Ysidro | 2 | San Diego County |
| Santee | 2 | San Diego County |
| Tecate | 2 | San Diego County |
| Boulevard | 1 | San Diego County |
| Campo | 1 | San Diego County |
12 further communities not listed. All California area codes →
Scope every community matched to 858. Source geoinfo-dataset (full_dataset) ZIP→NPA (2018 snapshot), GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated . Coordinates are place reference points, not boundaries.
We do not publish the NXX prefixes inside 858. The assignment of prefixes to rate centres comes from LERG routing data, which is proprietary, and we will not estimate it from postal data — ZIP codes and telephone prefixes do not map onto each other. Awaiting a clean-rights NPA-NXX source.
858 is the newer code here, added in 1999 over 619 (1982). The older code had run out of exchanges to assign, and an overlay avoids the alternative — splitting the region and forcing half its residents to renumber. New lines have been issued from 858 since.