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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.

Area code 925: NANPA facts
ItemValue
StateCalifornia
In service sinceMarch 14, 1998
Assigned by NANPAMay 19, 1997
OverlayNo
Parent area code (NANPA)510
Time zonePacific
Local calls within the code1 plus ten digits
Assigned central office codes640
Rate centers with codes17
Carriers holding codes32
Pooled codes446
Codes assigned since 202060
Relief planning in progressNo

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.

Most populous places with 925 exchanges
PlacePopulation (2024)Area codesExchangesCarriers
Concord, CA124,0169258920
Antioch, CA118,4539256718
Livermore, CA84,8679255019
Pittsburg, CA77,1319251912
Pleasanton, CA75,6649257616
Walnut Creek, CA70,81792510324
Danville, CA43,4109253814
Martinez, CA37,0069252210
Lafayette, CA25,371925159
Orinda, CA19,573925128
Moraga, CA16,698925117
Clayton, CA10,933925128

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.

Largest code holders in area code 925
Carrier (NANPA operating company)ExchangesShare
Pacific Bell20632%
New Cingular Wireless PCS, LLC487.5%
T-mobile USA, INC.446.9%
Mcimetro Access Transmission Services LLC396.1%
Cellco Partnership d/b/a Verizon Wireless - CA385.9%
U.s. Telepacific Corp. d/b/a TPX Communications375.8%
Level 3 Communications, LLC - CA335.2%
Onvoy, LLC - CA325.0%
Teleport Communications America, LLC - CA253.9%
Metropcs, INC.233.6%
Matrix Telecom, LLC. S/i/i Tnci - CA203.1%
Fractel, LLC142.2%

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 centers in area code 925 by assigned codes
Rate center (NANPA)PlaceCodes
WALNUT CRKWalnut Creek, CA103
CONCORDConcord, CA89
PLEASANTONPleasanton, CA76
ANTIOCHAntioch, CA67
LIVERMORELivermore, CA50
BSHP RNCHnot matched43
DUBLN-SNRMnot matched42
DANVILLEDanville, CA38
MARTINEZMartinez, CA22
ECONTRCOSTnot matched22
PITTSBURGPittsburg, CA19
LAFAYETTELafayette, CA15
ORINDAOrinda, CA12
CLAYTONClayton, CA12
MORAGAMoraga, CA11
PSBG WESTnot matched10
SUNOLnot matched9

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.

Area code 925: central office codes by decade assigned
Decade assignedExchangesShare
2000s5031%
2010s5132%
2020s6037%

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.