Area codes / California / 510
The 510 area code
510 is an area code in California, in the Pacific time zone. Get a local 510 number for your business, shared by everyone who answers it, or bring the 510 number you already have.
510 at a glance
- State
- California
- Time zone
- Pacific
- In service since
- 1991
- Overlay
- Shares its area with 341
- Local calls
- Seven-digit dialing within the area code
Get a 510 business number
When you sign up for Onyx Phone, you pick a local number by area code: search 510, narrow it by the next three digits or the last four if you want something memorable, and it's yours on the spot. Which numbers are free changes daily. If you don't find one you like, 341 covers the same area.
The number rings everyone you assign to it, in the browser, on the iPhone and Android apps, and on desk phones, and texts from it are unlimited once US carriers approve your business. Your plan includes one number for each user, and more numbers are $5 a month.
Calling 510 customers
Local calls within 510 can be dialed with seven digits. Callers are on Pacific time, so set your business hours to match if most of your customers are here.
Calls from Onyx Phone show your business number, and once your business is verified, your caller ID name too, so 510 customers see who's calling.
Questions about area code 510
What state is area code 510?
Area code 510 is in California.
What time zone is area code 510 in?
Area code 510 is in the Pacific time zone.
Is 510 an overlay area code?
Yes. 510 shares its area with 341. Numbers in either code ring the same region, and local calls there are dialed with all ten digits.
Can I get a 510 business number?
Onyx Phone sells US local numbers. When you pick your number, search the 510 area code; which numbers are free changes daily. If none are free, 341 covers the same area.
Can I keep the 510 number I already have?
Yes. Moving a number to Onyx Phone is free on every plan and usually takes 3 to 7 business days. You answer on a temporary number until it moves.
Included on every plan
Starter is $17, Business is $29, Scale is $42 per user a month, or less billed yearly. The plan includes a business number for each user and unlimited calling and texting in the US and Canada. Every plan starts with a 7-day free trial, and moving your current number over is free.
Area code data from the North American Numbering Plan Administrator (NANPA), file of October 24, 2026.