A new area code was implemented in Western Washington in 2017.
The area code, 564, was created to assign as numbers in the 360, 206, 253, and 425 area codes become exhausted.
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.
The 425, 206, and 253 area codes are not exhausted and are still available for service providers to assign to customers. Once these codes are nearing exhaustion the 564 overlay will go into effect for those areas.
* NEW * Docket UT-200753: On July 16, 2022 callers in the U.S. will be able to reach the National Suicide Prevention Hotline by dialing 988. Currently, callers can reach the hotline at 1-800-273-8255 (TALK). Link for the FCC’s Order adopting 988. In order for 988 to work, the FCC required Washington to implement 10-digit dialing for its Eastern Washington area code 509 starting in 2021. The entire state of Washington is now therefore operating under mandatory 10-digit dialing, even when making local calls.
- North American Numbering Plan Administrator website.