Washington State Area Codes and Numbering Issues

Washington State Number Plan Area (NPA) Projections

Washington state has six number plan areas (NPAs). Five are in western Washington; 206, 253, 360, 425, 564 NPAs and one in eastern Washington; 509 NPA. The 564 NPA is an overlay NPA for western Washington. The area code, 564, was created in 2017 to overlay the 360, 206, 253, and 425 as each of those area codes exhaust number resources.

Part of this roll out included the implementation of mandatory 10-digit dialing for all western Washington area codes, which required callers to dial all 10 digits of a telephone number, including area code, when making local calls. 

Washington state is ten-digit local dialing statewide.

Washington state area code exhaust projections are calculated by the Federal Communications Commission (FCC) North American Numbering Plan Administrator (NANPA) and current area code projections may be found at: https://nationalnanpa.com

Numbering Efficiency and Conservation in Washington State

Number resources are a public resource. The UTC and federal regulators have oversight of numbers in the North American Number Plan. The UTC has delegated authority over numbering matters in Washington state. The UTC Hs directed its staff to identify unused prefixes, monitor projected demand, research and implement conservation efficiencies, and require service providers to share prefixes in compliance with rules. The UTC and FCC require service providers to use the existing supply of numbers efficiently and conservatively.

Number Portability

Number portability allows a customer to retain their telephone number with a change of service provider, certain location, or service. The FCC (Order CC Docket 99-200) requires all service providers to port numbers.

  • Customers should direct number portability questions to their current company.
  • If you have problems with number porting after contacting your current company, you may contact the UTC Consumer Protection Help Line.
  • Telecommunications industry members may direct number portability inquiries to UTC Regulatory Service  telecom@utc.wa.gov

Area Code Changes

 Western Washington:

  • In 2016 in Docket UT-143787, the UTC approved a plan to overlay a new area code (564) over the current 206, 253, 360, and 425 area codes in a stepped approach as each area code exhausts.
  • Western Washington has mandatory ten-digit local dialing.

Eastern Washington:

  • The 509 number plan area (NPA) covers all of eastern Washington.
  • Eastern Washington has mandatory ten-digit local dialing.