Area code 925, Telephone prefix in East Bay counties, California
Area code 925 is a telephone prefix serving the inland portions of Contra Costa and Alameda counties in California. It covers cities such as Walnut Creek, Concord, Pleasanton, and other communities located between the coastal hills and the Central Valley.
The prefix was created in 1998 through a split from area code 510 to meet the growing demand for telephone numbers in the East Bay. The division followed economic development and population growth in the eastern suburbs of the San Francisco Bay Area.
The region within area code 925 connects numerous communities through BART stations, business centers, and residential neighborhoods across the East Bay.
All calls within this prefix area require ten-digit dialing, a change that took effect in October 2021. Mobile phones and landlines follow the same rules, meaning local numbers must be dialed with the area code included.
Before 2021, some phone numbers in this area used the 988 prefix, which had to be changed when 988 became the National Suicide Prevention Lifeline code. Affected households and businesses received new numbers to avoid confusion with the nationwide crisis hotline.
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