Skip to content
Country Dialing CodesConnecting a more open world A clearer
more connected world.
US area code · California

Area code 510

Where the 510 area code is, its overlay and how to dial a +1 510 number from anywhere.

CoversAlameda, CaliforniaTime zonePacific (PT)TypeOverlay
Quick answer

The 510 area code is in Alameda, California, United States (Pacific (PT)). To call from abroad: +1 510 555-0123. It is an overlay, so all 10 digits are dialled.

StateCalifornia
Main areaAlameda
Time zonePacific (PT)
TypeOverlay
10-digit dialingRequired
In service since25-Apr-1990

The 510 area code is a geographic North American Numbering Plan (NANP) code covering Alameda, California. It has been in service since 25-Apr-1990 and sits in the Pacific (PT) time zone.

Overlay 510 shares its region

Several area codes cover the same geographic area, so two neighbours can have different codes. Because of the overlay, you must dial all 10 digits (area code + number) even for local calls.

510341415

How to dial a 510 number

From abroad+1 510 555-0123
Within the US / Canada1 510 555-0123
Locally (same area)510 555-0123

Cities in the 510 area code

A 510 number is usually in one of these places in California — 2 counties.

Alameda AlamedaBerkeley AlamedaCastro Valley AlamedaEl Cerrito Contra CostaFremont AlamedaHayward AlamedaNewark AlamedaOakland AlamedaRichmond Contra CostaSan Leandro AlamedaSan Lorenzo AlamedaSan Pablo Contra CostaUnion City Alameda

Other California area codes

209213279310323341350357369408415424442530559562

Frequently asked questions

Where is the 510 area code?

The 510 area code is in Alameda, California, United States (Pacific (PT)).

Is 510 an overlay area code?

Yes. 510 overlays the same region as 341, 415, so callers dial all 10 digits.

Do I have to dial 10 digits for 510?

Yes — dial the area code plus the seven-digit number.

How do I call a 510 number from another country?

Dial your exit code (or +), then 1, then 510, then the number: +1 510 555-0123.

Source: NANPA numbering plan. An area code covers a region, not a precise address — a 510 number does not pinpoint a street or ZIP code.

Missed a call from +1 510?

In the 30 days to September 24, 2026, 565 unwanted calls showing a 510 number were reported to the US Federal Trade Commission, 49% of them recorded messages or robocalls. That puts 510 at #150 of 670 area codes reported.

Other297
Dropped call or no message74
Reducing your debt (credit cards, mortgage, student loans)56
Calls pretending to be government, businesses, or family and friends50
Before you call back
  • If you do not know anyone in California, do not call back: a genuine caller will leave a message or send a text.
  • Scammers fake the number shown on caller ID, so a 510 number can hide a caller anywhere in the world.
  • Never give a code received by text or a bank detail to an unknown caller. In the US, calls can be reported at reportfraud.ftc.gov.

Who issues +1 510 numbers

Phone companies hold blocks of numbers in each area code. The main holders in 510:

Pacific Bell 278New Cingular Wireless PCS, LLC 78T-Mobile USA, Inc. 65Cellco Partnership Dba Verizon Wireless 60Metropcs, Inc. 45Onvoy, LLC 37

About 25.9% of the 800 prefixes in use belong to mobile carriers: a 510 number is often a cell phone, and it may have moved to another carrier since.

Sources: FTC Do Not Call reported calls (numbers as reported by consumers, not verified), NANPA central office code assignments.

All US area codes United States +1 Map of area code 510 — cities & rate centres