$125 Cheap Alaska Airlines flights Seattle (SEA) to St. Louis (STL)

View $125 flight on Mon, Oct 27, 2025Opens in a new window

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$125 Cheap Alaska Airlines flights Seattle (SEA) to St. Louis (STL)

Prices were available within the past 7 days and start at $125 for one-way flights and $206 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Alaska Airlines
Tue, Sep 16 - Fri, Sep 26
SEA
Seattle
STL
St. Louis
$206 Roundtrip, found 7 hours ago
$206
Roundtrip
found 7 hours ago
Select Alaska Airlines flight, departing Tue, Sep 16 from Seattle to St. Louis, returning Fri, Sep 26, priced at $206 found 7 hours ago
Alaska Airlines
Fri, Aug 29 - Thu, Sep 4
SEA
Seattle
STL
St. Louis
$249 Roundtrip, just found
$249
Roundtrip
just found
Select Alaska Airlines flight, departing Fri, Aug 29 from Seattle to St. Louis, returning Thu, Sep 4, priced at $249 just found
Flights from Seattle (SEA) to St. Louis (STL)
Origin airport
Seattle - Tacoma Intl.
Destination airport
Lambert-St. Louis Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, Sun Country Airlines, United
Popular airline
Alaska Airlines
Distance
1705 mi
Average flight time
5 hours 53 mins

Frequently asked questions

How much is an Alaska Airlines flight from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL)?
You'll discover affordable return Alaska Airlines flights from $206 from SEA to STL by organizing your results from "Price (lowest to highest)" on Expedia. Or search for bargains from $125 for a one-way journey.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.
What is the cheapest month to fly from SEA to STL with Alaska Airlines?
Browse for one-way or return flights to St. Louis in January or February. You could find lower fares with Alaska Airlines during these off-peak travel months.
What is the cheapest time to book flights from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL) with Alaska Airlines?
Start searching one to three months ahead of your travel date to get cheaper fares on Alaska Airlines flights from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL). You can save 25% by booking your domestic flight 34 to 86 days in advance versus last-minute reservations made 6 to 12 days out. You could also cut costs by buying your fare on a Sunday, as it's 6% cheaper on average than a Monday, the most expensive day to book.* Get your timing right, and you can enjoy significant savings on domestic trips.*Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.
Does Alaska Airlines fly nonstop from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL)?
You can easily fly from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL) on one of Alaska Airlines's 7 direct weekly flights. Apply our "Nonstop" and "Airline" filters to find the Alaska Airlines flight that'll get you to STL at a time that suits you.
How long does it take to fly from SEA to STL with Alaska Airlines?
It takes approximately 3h 52m to travel nonstop from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL) with Alaska Airlines.
Which day of the week has the most Alaska Airlines flights from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL)?
If you're looking for flexibility, Thursday offers the most choice for Alaska Airlines flights from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL). You can pick from 2 different departures.
What is the earliest Alaska Airlines flight from SEA to STL?
Setting off from SEA at 8:00AM UTC-8, the earliest Alaska Airlines flight to STL arrives at 1:53PM UTC-6. Flying early means you're less likely to encounter delays or cancellations.* Prefer a later start? The last Alaska Airlines flight from SEA to STL departs at 6:09PM UTC-8 and touches down at 11:59PM UTC-6.*Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports does Alaska Airlines fly into in St. Louis?
Lambert-St. Louis Intl. Airport (STL) is the primary St. Louis hub for Alaska Airlines flights from Seattle - Tacoma Intl. Airport (SEA).
Why fly with Alaska Airlines from SEA to STL?
Alaska Airlines makes traveling from SEA to STL more enjoyable with a rewarding loyalty program and an excellent in-flight experience. You may even earn points with Mileage Plan. Don't forget to join our free One Key™ rewards program to earn OneKeyCash™*, which can be redeemed on future travel.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.
What type of plane does Alaska Airlines fly from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL)?
For the Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL) route, Alaska Airlines typically flies Boeing 737 MAX 9 and Boeing 737-800 planes. Remember that last-minute changes can occur for operational purposes, meaning your flight may be on a different aircraft.
Can I change or cancel my Alaska Airlines flight from Seattle - Tacoma Intl. Airport (SEA) to Lambert-St. Louis Intl. Airport (STL)?
Depending on your ticket type, a fee typically applies if you change or cancel your booking more than 24 hours after it's confirmed. To secure tickets with more flexibility, select our "No cancel fee" or "Changes included" filter when you search for flights. For more details on canceling or changing your reservation, visit "Trips," select your flight and click on "Manage Booking."
*Available to One Key members.