By plane
Seattle-Tacoma International Airport, IATA: SEA, called "SeaTac" by locals, connects Seattle to all regions of the world, with especially frequent transpacific routes. Competition is heavy on busy San Francisco Bay Area and Southern California routes. Non-stops to the following countries: Canada, China, United Arab Emirates, France, Germany, Iceland, Japan, South Korea, Mexico, Netherlands, Taiwan, and the UK. Transfers are required from the Caribbean and Central and South America.
Spokane International Airport, IATA: GEG. Most flights go to Seattle, Portland Oregon, Boise, Oakland across from San Francisco, Salt Lake City, Sacramento, Denver, Phoenix and Minneapolis. One flight to Chicago.
Portland International Airport, IATA: PDX is just one mile across the state line in Oregon. For Southwest Washington i.e. anything south of Chehalis along I-5 exit 77 this is the nearest major airport. One daily non-stop from Tokyo and Amsterdam.
Vancouver International Airport IATA: YVR is in Canada 27 miles 44 km from the border. You will have to go through U.S. customs at Blaine, Washington. For U.S. residents, going through customs twice probably isn't worth it unless you also want to visit Vancouver see Bellingham below. For Canadians wanting to go to the San Juan Islands, it's the best choice. Also has lots of international flights.
Tri-Cities Airport IATA: PSC is a commercial airport located 2 miles northwest of the city of Pasco and is the third largest commercial air terminal in the State of Washington. Flights go to Seattle, San Francisco, Los Angeles, Las Vegas, Mesa near Phoenix, Salt Lake City, Denver, and Minneapolis seasonal.
Bellingham International Airport IATA: BLI is a regional airport about 90 miles north of Seattle and 60 miles south of Vancouver, Canada. Allegiant and Alaska Airlines have jet service to Las Vegas, Los Angeles, Oakland, Mesa near Phoenix, San Diego, Honolulu and Palm Springs seasonal. There are many shorter flights mostly to Seattle with turboprop aircraft.
By train
Amtrak has 3 routes into Seattle's King Street Station. These are Amtrak Cascades and Coast Starlight, which serve the West Coast from Vancouver, BC to Los Angeles, and the Empire Builder which serves destinations to the East, running through Spokane, northern Montana, Fargo, St. Paul, Milwaukee, and arriving at Chicago as its terminus.
By bus
Greyhound (http://www.greyhound.com/...) has a number of bus stations throughout the state in metropolitan areas as well as the smaller micropolitan areas.