---
title: "Area code 925: California, United States"
url: "https://lookvalid.com/area-code/925.md"
canonical_url: "https://lookvalid.com/area-code/925"
last_updated: "2026-10-23"
type: "reference"
summary: "Area code 925 serves California, United States. Number formats, numbering rules, a live phone validator and the other codes in California."
---

# Area code 925: California, United States

Area code 925 serves California, United States. Number formats, numbering rules, a live phone validator and the other codes in California.

NANPA lists 637 central office codes (prefixes) in use in area code 925, held by 31 holders across 17 rate centers.
Pacific Bell holds the most prefixes, 206 (32%). 70% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
The FCC unwanted-call data has 2,414 complaints on file for 1,839 numbers in 925, most often filed as "Unwanted Calls". These are consumer reports, not findings.

## Facts

- 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

| 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% |

## Carriers

| 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.

## History

- 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.

## Nearest area codes

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).

## ZIP codes

25 ZIP codes fall in places that have a rate center in this area code. The places with the most are Concord, CA (8 ZIP codes), Moraga, CA (3 ZIP codes) and Antioch, CA (2 ZIP codes). A ZIP code and an area code are unrelated systems, so a ZIP code can sit in more than one area code and an area code spans many ZIP codes.

## Complaints on file

2,414 complaints for 1,839 numbers. Numbers whose latest complaint falls in each year:

- 2023: 94
- 2024: 68
- 2025: 90

## Questions

### 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.

Sources: NANPA central office code report dated 2026-10-17; NANPA NPA report dated 2026-10-18; FCC unwanted-call complaints, data fetched 2026-10-17; ZIP code places from GeoNames (CC BY 4.0).