Yes, charges to nonresidents for fishing charters are subject to retail sales tax. The sales tax exemption for items sold to residents of certain states to be used outside of Washington does not extend to charges for retail recreational services.
Starting October 1: Some business services are now subject to retail sales tax, as required by state law, ESSB 5814. When you buy these services, vendors should add sales tax to your bill. If you sell these services, you should begin collecting retail sales tax. Learn more about Services newly subject to retail sales tax.