£117 Cheap Flights from St. Louis (STL) to Seattle (SEA)

View £117 flight on Tue, 9 Jun 2026Opens in a new window

Flight 1

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

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Cheap Flights from St. Louis (STL) to Seattle (SEA)

Prices were available within the past 7 days and start at £117 for one-way flights and £289 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Alaska Airlines
Sat, 6 Jun - Wed, 10 Jun
STL
St. Louis
SEA
Seattle
£289 Return, found 3 days ago
£289
Return
found 3 days ago
Select Alaska Airlines flight, departing Sat, 6 Jun from St. Louis to Seattle, returning Wed, 10 Jun, priced at £289 found 3 days ago
Alaska Airlines
Sat, 6 Jun - Wed, 10 Jun
STL
St. Louis
SEA
Seattle
£297 Return, found 3 days ago
£297
Return
found 3 days ago
Select Alaska Airlines flight, departing Sat, 6 Jun from St. Louis to Seattle, returning Wed, 10 Jun, priced at £297 found 3 days ago
Alaska Airlines
Sat, 6 Jun - Wed, 10 Jun
STL
St. Louis
SEA
Seattle
£309 Return, found 3 days ago
£309
Return
found 3 days ago
Select Alaska Airlines flight, departing Sat, 6 Jun from St. Louis to Seattle, returning Wed, 10 Jun, priced at £309 found 3 days ago
Alaska Airlines
Mon, 3 Aug - Thu, 6 Aug
STL
St. Louis
SEA
Seattle
£316 Return, found 9 hours ago
£316
Return
found 9 hours ago
Select Alaska Airlines flight, departing Mon, 3 Aug from St. Louis to Seattle, returning Thu, 6 Aug, priced at £316 found 9 hours ago
Alaska Airlines
Sat, 6 Jun - Wed, 10 Jun
STL
St. Louis
SEA
Seattle
£319 Return, found 3 days ago
£319
Return
found 3 days ago
Select Alaska Airlines flight, departing Sat, 6 Jun from St. Louis to Seattle, returning Wed, 10 Jun, priced at £319 found 3 days ago
Alaska Airlines
Mon, 3 Aug - Thu, 6 Aug
STL
St. Louis
SEA
Seattle
£324 Return, found 9 hours ago
£324
Return
found 9 hours ago
Select Alaska Airlines flight, departing Mon, 3 Aug from St. Louis to Seattle, returning Thu, 6 Aug, priced at £324 found 9 hours ago
Alaska Airlines
Sat, 6 Jun - Wed, 10 Jun
STL
St. Louis
SEA
Seattle
£338 Return, found 3 days ago
£338
Return
found 3 days ago
Select Alaska Airlines flight, departing Sat, 6 Jun from St. Louis to Seattle, returning Wed, 10 Jun, priced at £338 found 3 days ago
Alaska Airlines
Mon, 3 Aug - Thu, 6 Aug
STL
St. Louis
SEA
Seattle
£339 Return, found 9 hours ago
£339
Return
found 9 hours ago
Select Alaska Airlines flight, departing Mon, 3 Aug from St. Louis to Seattle, returning Thu, 6 Aug, priced at £339 found 9 hours ago
Alaska Airlines
Wed, 22 Jul - Mon, 3 Aug
STL
St. Louis
SEA
Seattle
£342 Return, found 5 days ago
£342
Return
found 5 days ago
Select Alaska Airlines flight, departing Wed, 22 Jul from St. Louis to Seattle, returning Mon, 3 Aug, priced at £342 found 5 days ago
Alaska Airlines
Sat, 6 Jun - Wed, 10 Jun
STL
St. Louis
SEA
Seattle
£343 Return, found 3 days ago
£343
Return
found 3 days ago
Select Alaska Airlines flight, departing Sat, 6 Jun from St. Louis to Seattle, returning Wed, 10 Jun, priced at £343 found 3 days ago

Find the cheapest month to fly from St. Louis (STL) to Seattle (SEA)

April is typically the cheapest month to fly

From £134 - £218 per traveller.

Frequently asked questions

Which airlines fly direct from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
Enter STL to SEA and your travel dates, then apply the 'Nonstop' filter to see only direct flights.
How do I find cheap flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
To find a cheap flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.
What is the best airline to fly with from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
The best airline to fly with from St. Louis, MO (STL-Lambert-St. Louis Intl.) (STL) to Seattle, WA (SEA-Seattle - Tacoma Intl.) (SEA) will differ from traveller to traveller. If you like to fly early, AS offers early morning flights. If price is the most important factor, WN typically offers the lowest fares. WN offers the most daily flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) (STL) to Seattle, WA (SEA-Seattle - Tacoma Intl.) (SEA), which is brilliant if flexibility is what you value most. The best carrier for this journey could also be the one you have a loyalty membership with, as flying with that airline or another airline within the same alliance could help you collect points or enjoy lounge access.
What is the best time to fly from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
The best time to fly is usually mid-week (Tuesday or Wednesday) and during early morning hours as flights tend to be cheaper, less crowded, and generally more on-time. Avoid major holidays and peak vacation seasons for smoother travel. Combining off-peak days and hours often gives the best combination of cost, comfort, and convenience.
How many flights per day from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
There are approximately 1 connecting flight per day from St. Louis, MO (STL-Lambert-St. Louis Intl.) (STL) to Seattle, WA (SEA-Seattle - Tacoma Intl.) (SEA). For even more choice, look at flights that include layovers. You'll find around 122 connecting flights per day. Some common connection points include O'Hare Intl. (ORD), Denver Intl. (DEN), and Sky Harbor Intl. (PHX).
What is the earliest flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
The earliest flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) typically departs at approximately 5:00 AM local time, operated by American Airlines. This is a seasonal service active in December. An early departure like this can help you maximise your time at your destination. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.
What day of the week has the most flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
You'll typically find the most flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) on a Thursday, with around 86 flights available. This gives you plenty of options for your travel plans. Major airlines on this route include Southwest Airlines, United Airlines, and Alaska Airlines. Flight schedules are consistent throughout the week.
What are the most popular departure times for flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
The most popular departure times for flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) are in the morning, between 6am and 9am. About 32% of passengers prefer this time. Many major carriers, including Alaska Airlines, American Airlines and Delta, offer flights during this window. This timing works well because it allows you to get an early start on your travel day and arrive in Seattle with plenty of time to settle in.
How long does it take to fly from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
A nonstop flight from STL to SEA typically takes around 4 hours 20 minutes, covering approximately 1,705 miles. Connecting flights on this route usually add 4 hours 10 minutes to your travel time. Keep in mind that actual flight times can vary due to wind patterns, weather, and air traffic.
Can you fly business or first class from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
Select the "Business class" and "First class" filters when looking for STL to SEA flights on Expedia. This is the easiest way to compare prices, routes and flight times for your trip.
How do I earn miles on a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) flight with Expedia?
It's easy to earn miles on a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia. *Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.
What airports do you fly into for Seattle from Lambert-St. Louis Intl. (STL)?
If you're planning to travel to Seattle from Lambert-St. Louis Intl. (STL), you can fly directly into Seattle - Tacoma Intl. (SEA) Some flights may connect through major hubs like Seattle - Tacoma Intl. (SEA), O'Hare Intl. (ORD), Love Field (DAL) before reaching Seattle. Compare routes and airports on Expedia to find the best flight options for your travel plans.
Is it cheaper to buy a plane ticket from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) at the last minute?
Typically, booking a last minute flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) flight and hotel package?
Securing a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.)?
If you booked your St. Louis, MO (STL-Lambert-St. Louis Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.

Travel information

Origin airport
Lambert-St. Louis Intl.
Destination airport
Seattle - Tacoma Intl.
Airlines serving
Alaska Airlines
Return price
£289
Distance
2728 km
Average flight time
3 hours 23 mins

Book with confidence

Compare flights from St. Louis to Seattle easily and book with confidence

For travelling on business or for pleasure, Expedia makes it easy to book your flights from St. Louis to Seattle. Operating between them flights per day, 20 airlines cover the route. And fly direct, getting you to Seattle - Tacoma Intl. in just hours. If you have a preferred carrier, use our advanced search tool to find the right flight from Lambert-St. Louis Intl. to Seattle - Tacoma Intl..  

To make things even better, in the advanced search, you can also choose to fly economy, premium economy, business or first class, select your maximum number of stops, and pick your preferred departure and arrival time. You can also opt for refundable and direct flights. 

Grab a great deal on your flight from Lambert-St. Louis Intl. (STL) to Seattle - Tacoma Intl. (SEA)

The easiest way to view the best deals on flights from St. Louis to Seattle today is to enter your travel dates and hit search. From here, you can sort your results by price to see the cheapest flights first. Right now, return flights from Lambert-St. Louis Intl. to Seattle - Tacoma Intl. start at just £289 and range up to £343.  

To find an even better deal, try  

  • being flexible on your dates – midweek flights can be cheaper
  • looking for other airports near St. Louis and Seattle
  • booking your flight during June, the cheapest month on this route
  • varying your flight times – early morning and late at night are sometimes cheaper 

Why you should book your St. Louis to Seattle flight with Expedia!

We cater for all flight types, cabin classes and airlines. So whether you’re booking flights from Lambert-St. Louis Intl. to Seattle - Tacoma Intl. for a budget break or a business trip with a bit of pleasure thrown in, we make it easy to secure the seat that’s right for you.  

Thanks to our supersized inventory that offers great choice all in one place, you know you’ll get a great deal with Expedia. Especially if you bundle your flight together with your hotel, you will unlock amazing savings. For added peace of mind, you can choose flexible bookings or filter to find refundable options, so you won’t pay a fee to change your flight.  

Compare flights from St. Louis to Seattle easily and book with confidence

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*Available to Expedia members.