Area code 925
Where 925 is, how it is dialed, which carriers hold its numbers and how many of its codes are in use, from NANPA's 10/01/2026 files.
- State
- CA
- In service
- 1998
- Assigned codes
- 640of 800 possible
- Carriers
- 32
Area code 925 at a glance
Area code 925 is a geographic area code in California, in service since March 14, 1998, according to the North American Numbering Plan Administrator (NANPA). It is not part of an overlay, so every number in its territory starts with 925. It is in the Pacific time zone. The places with the most assigned exchanges include Walnut Creek, Concord, Pleasanton, Antioch, and Livermore. By population, its largest named places are Concord, Antioch, Livermore, Pittsburg, and Pleasanton.
| Item | Value |
|---|---|
| State | California |
| In service since | March 14, 1998 |
| Assigned by NANPA | May 19, 1997 |
| Overlay | No |
| Parent area code (NANPA) | 510 |
| Time zone | Pacific |
| Local calls within the code | 1 plus ten digits |
| Assigned central office codes | 640 |
| Rate centers with codes | 17 |
| Carriers holding codes | 32 |
| Pooled codes | 446 |
| Codes assigned since 2020 | 60 |
| Relief planning in progress | No |
Source: NANPA NPA report and utilized central office code file, both dated 10/01/2026.
Places served by 925
925 holds 2.9% of the 22,087 central office codes assigned in California, the 25th most of the state's 41 codes. 12 Census places could be matched to rate centers with 925 exchanges; the most populous are Concord (124,000), Antioch (118,000), Livermore (84,867), and Pittsburg (77,131). For a storefront or service area inside 925, the place pages show which prefixes are rated local there.
| Place | Population (2024) | Area codes | Exchanges | Carriers |
|---|---|---|---|---|
| Concord, CA | 124,016 | 925 | 89 | 20 |
| Antioch, CA | 118,453 | 925 | 67 | 18 |
| Livermore, CA | 84,867 | 925 | 50 | 19 |
| Pittsburg, CA | 77,131 | 925 | 19 | 12 |
| Pleasanton, CA | 75,664 | 925 | 76 | 16 |
| Walnut Creek, CA | 70,817 | 925 | 103 | 24 |
| Danville, CA | 43,410 | 925 | 38 | 14 |
| Martinez, CA | 37,006 | 925 | 22 | 10 |
| Lafayette, CA | 25,371 | 925 | 15 | 9 |
| Orinda, CA | 19,573 | 925 | 12 | 8 |
| Moraga, CA | 16,698 | 925 | 11 | 7 |
| Clayton, CA | 10,933 | 925 | 12 | 8 |
Population: Census Vintage 2024 estimates for the matched place. Exchanges and carriers: NANPA utilized code file.
Ten-digit and seven-digit dialing in 925
According to NANPA's dialing-plan data, local calls within 925 are dialed as 1 plus ten digits and toll calls as 1 plus ten digits. Ten-digit local dialing means the area code is part of how customers save and recognize your number, so print it in full everywhere.
Carriers with 925 numbers
32 carriers hold the 640 central office codes assigned in 925. Pacific Bell has the most, with 206 (32%). 446 of the codes (70%) are pooled, meaning the code holder shares blocks of 1,000 numbers with other carriers instead of using all 10,000 itself. Numbers can move between carriers through porting, so a code's holder tells you where the block started, not where every number lives now.
| Carrier (NANPA operating company) | Exchanges | Share |
|---|---|---|
| Pacific Bell | 206 | 32% |
| New Cingular Wireless PCS, LLC | 48 | 7.5% |
| T-mobile USA, INC. | 44 | 6.9% |
| Mcimetro Access Transmission Services LLC | 39 | 6.1% |
| Cellco Partnership d/b/a Verizon Wireless - CA | 38 | 5.9% |
| U.s. Telepacific Corp. d/b/a TPX Communications | 37 | 5.8% |
| Level 3 Communications, LLC - CA | 33 | 5.2% |
| Onvoy, LLC - CA | 32 | 5.0% |
| Teleport Communications America, LLC - CA | 25 | 3.9% |
| Metropcs, INC. | 23 | 3.6% |
| Matrix Telecom, LLC. S/i/i Tnci - CA | 20 | 3.1% |
| Fractel, LLC | 14 | 2.2% |
Carrier names are the operating company (OCN) names on NANPA's utilized central office code file dated 10/01/2026. A carrier holding a code may port numbers to other carriers.
Local calling areas in 925
NANPA assigns each central office code to a rate center, the local calling area that decides whether a call is local or toll. 925 has codes in 17 rate centers. The table lists the rate centers with the most codes, with the matching Census place where the abbreviation could be matched.
| Rate center (NANPA) | Place | Codes |
|---|---|---|
| WALNUT CRK | Walnut Creek, CA | 103 |
| CONCORD | Concord, CA | 89 |
| PLEASANTON | Pleasanton, CA | 76 |
| ANTIOCH | Antioch, CA | 67 |
| LIVERMORE | Livermore, CA | 50 |
| BSHP RNCH | not matched | 43 |
| DUBLN-SNRM | not matched | 42 |
| DANVILLE | Danville, CA | 38 |
| MARTINEZ | Martinez, CA | 22 |
| ECONTRCOST | not matched | 22 |
| PITTSBURG | Pittsburg, CA | 19 |
| LAFAYETTE | Lafayette, CA | 15 |
| ORINDA | Orinda, CA | 12 |
| CLAYTON | Clayton, CA | 12 |
| MORAGA | Moraga, CA | 11 |
| PSBG WEST | not matched | 10 |
| SUNOL | not matched | 9 |
How full is area code 925?
An area code has 800 possible central office codes that start with 2 through 9, a few of which are reserved (such as N11 service codes and 555). 640 are assigned in 925, 80% of 800. 60 were assigned in 2020 or later.
| Decade assigned | Exchanges | Share |
|---|---|---|
| 2000s | 50 | 31% |
| 2010s | 51 | 32% |
| 2020s | 60 | 37% |
Assignment dates as recorded in NANPA's utilized code file; codes without a recorded date are excluded.
A local 925 number on Callata
Callata Office costs $99 per month for up to 5 people, and each additional user is $20 a month. That covers up to 3 local numbers, calling from a browser or your cell, transcribed voicemail, recorded calls with AI summaries, after-hours routing and E911 on each number.
If you already have a number in area code 925, porting it to Callata is free. Texting from a local number requires a one-time carrier registration (10DLC, $49), and the numbers available in any area code depend on carrier inventory when you choose them.
Optional AI agents (receptionist, sales, support or scheduler) can answer calls after hours or when nobody picks up, take messages, text, email and transfer to your team. They are billed from prepaid AI minutes at $0.25 per minute, identify themselves as AI, and may only place outbound calls to people who consented, between 8am and 9pm.
Frequently asked questions
Where is area code 925?
925 is a geographic area code in California. Places with the most assigned exchanges include Walnut Creek, Concord, Pleasanton, and Antioch.
What time zone is area code 925 in?
NANPA lists 925 in the Pacific time zone.
When did area code 925 go into service?
NANPA records an in-service date of March 14, 1998. The code was assigned on May 19, 1997.
Is 925 an overlay area code?
No. NANPA does not list 925 as part of an overlay.
Can my business get a 925 phone number?
Callata includes up to 3 local numbers on its $99/month plan (5 users included). Which 925 numbers are open depends on carrier inventory when you choose, and you can port an existing number for free.