925 area code: East Bay, California, time zone and cities
Area code 925 covers the inland East Bay in California: all of Contra Costa County except its western part, and southeastern Alameda County. It was split from area code 510 in 1998.
Quick facts
- Location
- Inland East Bay, California
- State
- California
- Time zone
- Pacific TimeLocal time now:
- Overlay
- No. 925 is the only area code for its area.
- In service since
- 1998
Cities and places in area code 925
- Dublin
- Pleasanton
- Livermore
- Sunol
Dublin, Pleasanton, Livermore and Sunol are in Alameda County. 925 also covers most of Contra Costa County.
Counties
- Contra Costa County (all but the western part, El Cerrito to Crockett)
- Alameda County (southeastern part)
Area codes that share or border 925
925 has no overlay. It is the only area code for its area.
Nearby
- 209 CA
- 279 CA
- 341 CA
- 350 CA
- 369 CA
- 408 CA
- 510 CA
- 669 CA
- 707 CA
- 916 CA
Is a call from 925 a scam?
The area code alone says nothing about the caller. It shows where the number was set up. It does not show who is calling or where they are. The FTC says scammers can make any name or number show up on caller ID. This is called spoofing, and it can make a call look local when it comes from anywhere in the world.
Signs of a phone scam, from the FTC:
- The caller says you won a prize, but you have to pay to get it.
- The caller says you will be arrested or fined unless you pay right away. Real law enforcement and federal agencies do not call and threaten you.
- The caller insists you pay by gift card, wire transfer, cryptocurrency or a payment app.
- The caller says they are from a government agency and asks for your Social Security number.
What to do:
- If you get a robocall, hang up. Do not press any number, which could lead to more robocalls.
- Ask your phone carrier what call blocking it offers.
- Report unwanted calls at DoNotCall.gov. If you lost money, report it at ReportFraud.ftc.gov.
How to get a 925 phone number
For an AI agent or a business
Our API lines are real T-Mobile mobile numbers for texts, or for texts and calls over SIP, rented by the month. Add "area_code": "925" to an order to ask for 925 numbers.
The area code is a request and is not guaranteed. Numbers come from our stock and from the carrier, so some can have another area code. If the carrier cannot fill the request within about an hour, we send numbers from other area codes.
Numbers for AI agents and businesses
For your own phone
Our T-Mobile Talk & Text line asks where your number should come from at checkout. If you live in the 925 area, give your address, and we ask the carrier for a number local to your ZIP code. The carrier picks the area code, so a 925 number is not guaranteed.
Our Unlimited line has no area code choice.
Questions about area code 925
Where is area code 925?
Area code 925 covers the inland East Bay in California: all of Contra Costa County except its western part, and southeastern Alameda County. It was split from area code 510 in 1998.
What time zone is area code 925 in?
Pacific Time.
Does area code 925 have an overlay?
No. 925 is the only area code for its area.
When did area code 925 start?
NANPA lists 925 as in service since 1998.
Is a call from area code 925 a scam?
The area code alone does not make a call a scam. It shows where the number was set up. The FTC says scammers can make any number show up on caller ID. If you get a robocall, hang up without pressing any number, and report unwanted calls at DoNotCall.gov.
How can I get a phone number with area code 925?
For an AI agent or a business, add "area_code": "925" to an API order. For your phone, if you live in the 925 area, give your address at checkout for our T-Mobile Talk & Text line and we ask the carrier for a number local to your ZIP code. Either way the area code is a request and is not guaranteed.
Sources: NANPA area code database, file of November 3, 2026 (state, time zone, overlays, year in service); Wikipedia, "Area code 925", revision of February 27, 2026 (area, places and neighbors); FTC, "Phone Scams" and "How To Block Unwanted Calls" (call advice). Checked November 3, 2026.