San Francisco, December 19, 2023 - 

The California Public Utilities Commission (CPUC) has acted to ensure that telephone numbers continue to be available to meet the demand in the geographic region served by the 559 area code by approving a second area code (called an overlay) that will provide additional numbering resources while minimizing customer inconvenience. The new area code to overlay the 559 area codes is 357.

The 559 area code is projected to run out of available prefixes (the first three numbers after the area code in a telephone number) by September 2025. The CPUC’s action on Dec. 14, 2023, approves the request of the North American Numbering Plan Administrator, the neutral third-party area code relief planner for California, for an area code overlay to provide additional numbering resources to meet the demand for telephone numbers while minimizing customer inconvenience. No existing customers will be required to change their area code or specific telephone number. The new overlay area code of 357 will be available for new telephone number assignments in the same region as the 559 area code upon exhaust of available prefixes in the existing 559 area code.

The 559 area code covers central California in the San Joaquin Valley, including all or portions of Fresno, Madera, Mariposa, Merced, Tulare, and Kings counties. It serves cities and communities including but not limited to Clovis, Coalinga, Fresno, Madera, Porterville, Reedley, Selma, and Visalia, as well as unincorporated areas.

An area code overlay adds an additional area code to the geographic region served by the existing area code(s). Therefore, multiple area codes co-exist within the same geographic region. Existing 559/357 customers will retain their area code and specific telephone number(s). Customers will continue to dial the three-digit area code for all calls to and from telephone numbers with the 559 and 357 area codes. The price of a call will not change due to the overlay. Customers can still dial just three digits to reach 911, as well as 211, 311, 411, 511, 611, 711, and 811.

Below are some tips to help prepare for the area code overlay:

  • Contact security or alarm vendors to update dial-up numbers to avoid a break in security routines and contacts.
  • Reprogram equipment or features, e.g., automatic dial, speed-dial, call forwarding, modems for computer or Internet dial-up access, etc.
  • Update items like stationery, checks, etc., to include your area code + telephone number.
  • Provide your area code and telephone number, not just the telephone number, as needed.
  • When asking for someone’s number, remember to ask for the area code too.
  • Remember that the previous area codes and the new area code will co-exist within the same geographic region.

The 559 area code was formed in 1998 when the CPUC approved an area code split of the 209 area code, introducing the 559 area code.

The decision is available here.

Documents related to the proceeding are available here.

More information on 559 area code is available here.


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