Wash. Rev. Code § 28A.410.252
The agency responsible for educator certification shall adopt rules for professional certification that identify an expedited professional certification process for out-of-state teachers who have five years or more of successful teaching experience, including a method to determine the comparability of rigor between the Washington professional certification process and any United States federally issued or state-issued advanced level teacher certification process that allows an individual to teach internationally. A professional certificate must be issued to these experienced out-of-state teachers if the teacher holds a United States federally issued or state-issued advanced level teacher certificate that allows the individual to teach internationally and that has been determined to be comparable to the Washington professional certificate.
RCW 28A.410.252