Book a Flight +some taxes, additional fees apply   Seattle, WA to Denver, CO Current Fare : USD 116.00+  How many travelers are there?  Anyone under age 18 traveling alone? Adults 12-64:  0 1 2 3 4 5 6 Children 2-11:  0 1 2 3 4 5 Seniors 65+:  0 1 2 3 4 5 6