Cheap flights from St. Louis to Seattle (XLS to SEA) - Expedia

An Alaska Airlines plane taking off with a snow-capped mountain in the background.

Popular airlines from St. Louis (XLS) to Seattle-Tacoma International Airport (SEA)

Be in the know
Get alerts if flight prices drop or rise*
Book smarter
Save up to 45% on select hotels after you book a flight*
Earn twice
Earn your airline miles on top of our rewards
Sign in

Travel information

Origin airport	St. Louis
Destination airport	Seattle-Tacoma International Airport
Distance	9,840 km away

*Available to One Key members.