Get Ready to Dial More Digits – 510 Area Code Getting an Overlay

Becomes Mandatory - June 22nd

Beginning on June 22nd, Piedmonters will be required to change their dialing habits, both on landline and mobile phones, when making a phone call. This is the result of the new 341 area code being overlaid on to the 510 area code, which is running out of numbers for assignment.

  • Calls to 911 will not be affected in any way. Both land line and mobile phones will still be able to call 911 without having to dial any additional digits.
  • Land line users will have to dial eleven digits to make a local call. For example, to reach City Hall, a resident will need to dial 1 (510) 420-3040.
  • Mobile phone users will have to dial either eleven digits, similar to a land line, or ten digits, (510) 420-3040.

With the proliferation of mobile computing and telephony devices, each requiring its own telephone number, the 510 area code is projected to shortly run out of numbers. Rather than geographically separating area codes, the current practice is to overlay a new area code over an existing one. The overlay of one area code onto another allows existing numbers to remain the same, while providing additional numbers for future assignment.

Residents with devices that are preprogrammed to call a telephone number, such as medical and security monitoring systems, gates, call forwarding services, and or voicemail services should contact their provider to ensure that their systems have been updated before the mandatory ten or eleven digit dialing comes in to effect.

The introduction of the 341 area code will not change the cost of calls, or what is considered a local call.