Geographic Coverage & Key Cities

The 925 area code spans approximately 25 cities in California’s East Bay region, covering all of Contra Costa County and the eastern portions of Alameda County. It serves a population of about 2.8 million people and remains the sole area code for this region, with no overlays.

Originally introduced in 1998 due to the rapid growth of the tech economy, 925 remains one of the few major area codes in California not yet split or overlaid. The region it serves includes a blend of suburban comfort, business innovation, and natural beauty.

Key Economic Zones & Business Hubs

  • Tri-Valley Tech Corridor: Pleasanton, Dublin, and Livermore are home to startups, R&D labs, and enterprise satellite offices.
  • Bishop Ranch (San Ramon): A major business district housing corporate HQs, financial services, and regional operations.
  • Wine & Tourism: Livermore Valley’s wineries and hospitality scene drive seasonal traffic and local commerce.
  • Healthcare & Wellness: Walnut Creek’s medical district supports advanced care centers and specialty practices.
  • Retail & Services: Concord, Antioch, and Walnut Creek anchor regional shopping, dining, and lifestyle hubs.
  • Strategic Industries: Technology, healthcare, real estate, logistics, education, hospitality, and financial services.

Time Zone & Business Impact

The 925 area code operates on Pacific Time Zone (PT)—Pacific Standard Time (UTC-8) from November to March and Pacific Daylight Time (UTC-7) from March to November.

Daylight saving time transitions can affect business communications if not accounted for. This is especially important when scheduling meetings or handling clients on the East Coast or in Europe, where DST dates may differ.

Time Zone Advantages

  • West Coast Alignment: Perfect for coordinating with Silicon Valley, San Francisco, and the broader Pacific tech corridor.
  • East Coast Overlap: Allows seamless communication during morning hours with teams in New York, D.C., and other Eastern cities.
  • Automatic Time Adjustments: AI answering services like Goodcall handle daylight saving changes and caller time zones without manual setup.
  • Smarter Scheduling: Tools synced with Pacific Time reduce errors, missed calls, and double bookings—especially for remote teams and national clients.