510 area code — Oakland:main-piedmont Da, CA geographic

Data: NANPA public reports, current as of July 28, 2026.

Phone numbers beginning 510 are registered to the Oakland:main-piedmont Da area of California (Pacific time zone). The code entered service on September 2, 1991. The same territory is also served by its overlay code (341/510 complex). Keep in mind the code identifies where the number was registered; the person calling may be elsewhere.

The code currently holds 784 working prefixes, held by 31 different carriers. Of these, 513 are pooled prefixes shared by multiple carriers. Numbers are anchored to 13 rate centers — billing localities that fix where each prefix belongs.

If a 510 call asks for money or personal data, treat the displayed number as unverified: hang up and reach the organization through its published number. Numbering data locates numbers, not callers.

The code was carved out of 415 (1991). As demand grew it in turn gave rise to 925 (1998), 341 (2019).

The current NANPA exhaust forecast for the 341/510 complex is 4Q 2073.

Local calls inside 510 are dialed 1+10D.

Largest localities in 510

FAQ

Will 510 run out of numbers?

NANPA's current forecast projects exhaust in 4Q 2073 — decades of capacity remain.

Why am I getting spam calls from 510 numbers?

Scammers spoof recognizable area codes so calls look local or familiar. A displayed 510 number does not prove the call originated there — see our guide to spotting spoofed calls.

Where is a 510 number from?

510 is assigned to Oakland:main-piedmont Da and surrounding areas of California in the Pacific time zone. The three digits after the area code (the prefix) narrow it down to a rate center.