The 510 area code home to Oakland, Berkeley, Alameda, Richmond, and much of California’s East Bay now shares its map with the 341 overlay. The change guarantees plenty of phone numbers without forcing anyone to give up a long time 510 line, but it also cements ten digit dialing for every local call. Use this quick guide to stay compliant and connected.
New 341 Area Code Overlay
Instead of carving the region into smaller zones, regulators simply layered 341 on top of 510. Existing numbers don’t change; new lines may receive 341. Because two codes now serve one geography, callers must dial the area code plus the seven digit number for all local calls.
510 Area Code Regions Affected
The overlay covers most of western Alameda and Contra Costa counties, including:
- Oakland, Berkeley, Alameda
- Fremont, Hayward, San Leandro
- Richmond, El Cerrito, Albany
- Emeryville, Piedmont, Albany, Kensington, and surrounding communities
Dialing Rules
Landlines: Dial 1 + area code + phone number (11 digits total).
Mobile phones: Dial area code + phone number (10 digits) or 1 + area code + number either works.
Seven digit dialing no longer completes a call.
Ten digit dialing has been mandatory since June 22 2019.
Key Dates for the 341 Roll Out
| Date | Milestone |
|---|---|
| Dec 15 2018 | Optional 10 /11 digit dialing begins (seven digits still work) |
| Jun 22 2019 | Mandatory 10 /11 digit dialing for all local calls |
| Jul 22 2019 | First 341 numbers become available for new service |
What Stays the Same
- Your existing 510 number remains unchanged.
- Local calling areas and pricing stay identical.
- Emergency services (911) and other three digit codes still dial with three digits.
- Long distance rules and toll rates are unaffected.
Frequently Asked Questions
Why pick an overlay instead of a geographic split?
Overlays avoid forcing residents and businesses to change long standing numbers, making the transition less disruptive and less costly.
Will caller ID look odd to customers?
No. A 341 prefix simply signals a newer assignment within the same East Bay footprint.
Do mobile users have to dial “1”?
Most wireless carriers complete calls with either ten or eleven digits. Landlines generally require the leading “1.”
Does the overlay raise call charges?
No. The overlay does not alter rate center boundaries or tariffs; your plan remains the same.
Need Help?
Check the California Public Utilities Commission or North American Numbering Plan Administrator (NANPA) websites for regulatory details. If you manage high volume voice traffic, our telecom engineers are available 24 / 7 to help update SIP trunks, E 911 records, and auto dialers.
