Area code
925
925 is a United States area code. Under the North American Numbering Plan it belongs to California, which has 41 area codes in total.
Validate a number in 925
Paste a full number and the tool checks it against the numbering plan. It returns the standard formats, the line type the plan assigns and the area code region.
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Area code 925 at a glance
NANPA lists 637 central office codes (prefixes) in use in area code 925, held by 31 holders across 17 rate centers.
| Fact | Value |
|---|---|
| In service since | 1998-03-14 |
| Time zone | Pacific (P) |
| Prefixes in use | 637 |
| Pooled prefixes | 443 (70%) |
| Rate centers | 17 |
| Companies holding prefixes | 31 |
| Assignment dates on file | 2001-01-26 to 2026-07-30 (158 prefixes) |
| ZIP codes in its places | 25 |
Rate centers in area code 925
| Rate center | Prefixes | Share |
|---|---|---|
| WALNUT CRK | 102 | 16% |
| CONCORD | 89 | 14% |
| PLEASANTON | 76 | 12% |
| ANTIOCH | 67 | 11% |
| LIVERMORE | 49 | 8% |
| BSHP RNCH | 43 | 7% |
| DUBLN-SNRM | 42 | 7% |
| DANVILLE | 38 | 6% |
| 9 other rate centers | 131 | 21% |
Who holds the prefixes in 925
Pacific Bell holds the most prefixes, 206 (32%). 70% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
| Holder | Prefixes | Share |
|---|---|---|
| Pacific Bell | 206 | 32% |
| Mcimetro Access Transmission Services | 48 | 8% |
| New Cingular Wireless PCS | 48 | 8% |
| T-Mobile USA | 43 | 7% |
| Verizon Wireless | 38 | 6% |
| TPX Communications | 37 | 6% |
| 25 other carriers | 217 | 34% |
A prefix holder is the company a code was assigned to, not necessarily a number's current carrier, because numbers can be ported to another company. Find which carrier a number is on, or browse the prefix holders.
History of area code 925
- 1991-09-02 Area code 510, named as the parent of 925 in the NANPA report, was in service.
- 1998-03-14 Area code 925 went into service.
Area codes nearest to 925
Distance is measured between the centers of the ZIP code places each area code serves, so it is a rough guide.
ZIP codes in area code 925
25 ZIP codes fall in places that have a rate center in this area code.
| Place | ZIP codes |
|---|---|
| Concord, CA | 8 |
| Moraga, CA | 3 |
| Antioch, CA | 2 |
A ZIP code and an area code are unrelated systems. A ZIP code can sit in more than one area code, and an area code spans many ZIP codes.
Complaints on file for 925 numbers
2,414 FCC complaints are on file for 1,839 numbers in 925, most often filed as "Unwanted Calls". These are unverified consumer reports.
| Year of latest complaint | Numbers |
|---|---|
| 2023 | 94 |
| 2024 | 68 |
| 2025 | 90 |
Other area codes in California
California is one state with 41 area codes in the NANPA table. 925 is one of them.
- 209
- 213
- 279
- 310
- 323
- 341
- 350
- 357
- 369
- 408
- 415
- 424
- 442
- 510
- 530
- 559
- 562
- 619
- 626
- 628
- 650
- 657
- 661
- 669
- 707
- 714
- 738
- 747
- 760
- 805
- 818
- 820
- 831
- 837
- 840
- 858
- 909
- 916
- 949
- 951
Next to 925 in the numbering table
These are the codes just before and after 925 when all are sorted by number. They are neighbours on the list, not necessarily on the map.
What the area code does and does not tell you
A number that starts with 925 was first assigned in California. That is a fact about where the number began, and it is a useful hint when you check a form entry, for example a billing address in California next to a 925 phone number.
It does not show where the person is today. A number stays with its owner after a move or a change of provider (number portability), and mobile numbers travel with the handset. The area code also cannot tell you whether the line is active, who the carrier is, or whether the number is mobile or fixed: the plan shares those ranges. Read more about the area code, the numbering plan and line type.
Check numbers in bulk with the API
| Product | Credits | Docs |
|---|---|---|
| Phone Numbering-Plan Validation | 1 credit per valid number | API docs |
| Phone Intelligence (carrier and line status) | 1 credit per check (invalid numbers outside the US and Canada are free) | Product page |
Questions about area code 925
Where is area code 925?
NANPA assigns area code 925 to California, United States.
In which state does area code 925 sit?
California. 925 is one of 41 area codes the NANPA table assigns to the state.
Which places does area code 925 cover?
The places with the most ZIP codes among the rate centers in 925 are Concord, CA, Moraga, CA and Antioch, CA. The rate center list on this page shows all of them.
Who owns area code 925?
NANPA assigns area codes. Within 925, Pacific Bell holds the most prefixes, 206 prefixes or 32%.
Which time zone does 925 use?
The NANPA NPA report lists the time zone for 925 as Pacific (P).
What year did 925 enter service?
The NANPA NPA report gives an in-service date of 1998-03-14, so 925 has been in use since 1998.
Does area code 925 have an overlay?
The NANPA NPA report lists no other area code in an overlay with 925.
Which area codes are nearest to 925?
The area codes closest to 925, measured between the centers of the ZIP code places they serve, are 341 (about 13 miles), 510 (about 13 miles), 650 (about 33 miles), 415 (about 35 miles) and 628 (about 35 miles).
How many prefixes does area code 925 have?
NANPA's report dated 2026-10-17 lists 637 prefixes in service in 925, spread over 17 rate centers and 31 holders.
Are there complaints about 925 numbers?
The FCC data on file has 2,414 complaints for 1,839 numbers in 925. They are unverified consumer reports. A number with no complaints on file is not proven safe.
Area code assignments: North American Numbering Plan Administrator NPA report, file dated 10/17/2026, retrieved 2026-10-17. Source file. New codes are assigned several times a year. Prefixes, rate centers, holders, time zone, in-service date and overlays: NANPA central office code report dated 2026-10-17 and NPA report dated 2026-10-18. Complaints: FCC consumer complaints open data, fetched 2026-10-17. ZIP code places: Postal code places and coordinates: GeoNames (geonames.org), licensed CC BY 4.0.