The only airline that services San Juan Island is Kenmore Air. They provide flights between Seattle and Friday Harbor, by land or sea.
Bus transportation from Sea-Tac International Airport is provided by two services. Bellair – Airporter Shuttle, which will deliver you to the Anacortes Ferry Dock and Island Airporter, which will bring you to Friday Harbor.
By Sea from Seattle:
One way to have a nice boating experience is taking a Victoria Clipper vessel from Seattle to our public dock in Friday Harbor. As of this writing, the summer schedule has not be posted.