Area code 510: California
Area code 510 is a US state area code for California, on Pacific Time. It has 785 prefixes in service across 13 rate centers, the largest being Oakland:Main-Piedmont Da, Hayward and Fremont-Newark:Main Da. It shares its area with 341, so local numbers there can start with any of them. Local calls there take 1 + 10 digits.
Local time in area code 510
America/Los_Angeles
Prefixes in service
785 of 792 possible
13 rate centers
Area code 510 facts
| Location | California, United States |
|---|---|
| Time zone | Pacific Time |
| Overlays | 341 |
| Split from | 415 |
| In service since | September 2, 1991 |
| Local calls | 1 + 10 digits |
| Carrier | Not shown. An area code is where a number was issued; numbers port between carriers. Check line type |
Which cities and towns use area code 510?
NANPA records each prefix against a rate center, the local billing area a number belongs to, usually named after its main town. These are the 510 rate centers with the most prefixes in service. 1 smaller ones aren't listed.
| Rate center | Prefixes |
|---|---|
| Oakland:Main-Piedmont Da | 204 |
| Hayward | 117 |
| Fremont-Newark:Main Da | 81 |
| Oakland:Berkeley Da | 70 |
| Oakland:Trinidad Da | 60 |
| Richmond | 53 |
| Fremont-Newark:Oliver Da | 45 |
| Oakland:Alameda Da | 42 |
| Oakland:Fruitvale Da | 39 |
| El Sobrante-Pinole | 28 |
| Fremont-Newark:Greenleaf Da | 25 |
| Hercules-Rodeo | 14 |
Source: NANPA central office code assignments, file dated 10/17/2026. Each prefix holds up to 10,000 numbers.
How do I dial a 510 number?
NANPA's dialling plan for 510: local calls inside the code take 1 + 10 digits, toll calls 1 + 10 digits. From another area code, dial 1 first. From abroad, use +1. The examples use 555-0147, from a range reserved for fictional numbers.
| Local call inside 510 | 1-510-555-0147 |
|---|---|
| From another US or Canadian area code | 1-510-555-0147 |
| From outside North America | +1 510 555 0147 |
| E.164, for CRMs and SMS tools | +15105550147 |
When did area code 510 start?
Area code 510 went into service on September 2, 1991, split from 415. Today 510 and 341 cover the same area as an overlay, which is why 10-digit dialling is needed for local calls there.
Tools for 510 numbers
- Area code lookup
Look up any code or a whole list of numbers, or find the codes for a state or city.
- Area code time zone
Local time for a list of numbers, with a callable-now flag.
- NPA-NXX lookup
Rate center and state for one prefix, a level below the area code.
- TCPA calling hours checker
Whether it's inside the federal 8 a.m. to 9 p.m. calling window there now.
Next step
A 510 number tells you where it was issued, not what it is now.
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Area code 510 questions
- What state is area code 510?
- Area code 510 is in California, United States. Its largest rate centers by number of prefixes are Oakland:Main-Piedmont Da, Hayward, Fremont-Newark:Main Da, Oakland:Berkeley Da and Oakland:Trinidad Da.
- What time zone is area code 510 in?
- Pacific Time.
- What area codes overlay 510?
- 341. An overlay adds a new code to the same area instead of splitting it, so neighbours can have different area codes and local calls need 10 digits.
- When did area code 510 start?
- Area code 510 went into service on September 2, 1991, split from 415.
- Is a 510 number a cell phone or a landline?
- The area code can't tell you. In the US and Canada mobiles, landlines and VoIP lines share area codes and prefixes, and numbers move between carriers and line types. Only a live line-type lookup answers it for one number.
- How many phone numbers does area code 510 have?
- 785 of its 792 possible prefixes are in service, and each prefix holds up to 10,000 numbers. That counts prefixes assigned to carriers, not numbers in use.
Other area codes in California
209213279310323341350357369408415424442530559562619626628650657661669707714738747760805818820831837840858909916925949951
Sources
Location, overlays, in-service date and dialling plan: NANPA NPA database, file dated 10/16/2026. Prefixes and rate centers: NANPA central office code assignments, 10/17/2026. Time zones mapped to the IANA time zone database. By the SimpleVerifier Team; how we build these pages.