510 Area Code — CA
Area code 510 serves CA in the Pacific time zone, in service since 1991. The FCC has 93 unwanted-call complaints against 90 different 510 numbers on record. Look up the exact number that called you below.
Most-reported 510 numbers
Ranked by FCC unwanted-call complaints. Click a number for its full report.
510 unwanted-call complaints, last 12 months
Monthly FCC complaint volume against 510 numbers. Spikes usually mark an active robocall campaign cycling through the code.
About area code 510
- Serves
- CA
- Time zone
- Pacific
- In service since
- 1991-09-02
- Overlay
- Yes — 10-digit dialing
Source: NANPA numbering records, refreshed weekly.
Spam calls from 510? What to know
Seeing repeated missed calls from 510 numbers you don't recognize is the classic signature of neighbor-spoofing robocall campaigns. The caller isn't necessarily in CA — spoofing software displays whatever digits the campaign chooses. Never call unknown numbers back; look them up first, and report unwanted calls to the FCC to build the public record.
Area code 510 FAQs
Where is area code 510?
Area code 510 serves CA, in the Pacific time zone. It is part of an overlay complex, so multiple area codes serve the same territory and 10-digit dialing is required. It has been in service since 1991.
Why do I keep getting calls from 510 numbers?
Robocallers use "neighbor spoofing" — displaying a number with a local area code to make you more likely to answer. A call showing area code 510 may not originate from CA at all. Look up the full 10-digit number on this site to see its complaint history before calling back.
Are 510 numbers safe to call back?
Area codes themselves are neither safe nor unsafe — 510 contains millions of legitimate lines alongside any spoofed or spam numbers. The FCC has logged 93 unwanted-call complaints against 90 distinct 510 numbers in our current data window. Check the specific number's report page before returning a missed call.