Published: August 04, 2023
Back in 2017 the western portion of Washington state served by NPA 360 received an overlay Numbering Plan Area as a relief method for the aforementioned area code. At the time, plans were announced for this same NPA 564 to eventually cover the other three Numbering Plan Areas serving Western Washington, namely area codes 206, 253 and 425.
This year in June the Washington Utilities and Transportation Commission finally approved an overlay over the 206 NPA - the area code serving the city of Seattle and other nearby places like Mercer Island or Vashon. From June 10, 2025 area code 564 will also be overlaid on NPA 206, serving the exact same geographic locations.
See official NANPA announcement and rate center map of the new overlay complex 206/564 (PDF document).