Copalis State Airport (FAA LID: S16) is a state owned, public use airport in Grays Harbor County, Washington, United States. Formerly known as Copalis Beach State Airport, it is located near Copalis Beach, Washington.

The airstrip is located on an ocean beach near the mouth of the Copalis River, in the North Beach Seashore Conservation Area, adjacent to the Olympic Coast National Marine Sanctuary. It is the only airport in Washington State where landing on the beach is legal.