HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Seattle

$59+ Cheap flights from St. Louis to Seattle (STL - SEA)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 1/7. Fares are subject to change and may not be available on all flights or dates of travel.
STL — SEA
Dec 12 — Dec 191
Fri 12/12
Fri 12/19
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from St. Louis to Seattle with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheapflights Tip: The best prices from Lambert-St Louis to Seattle/Tacoma Intl are usually found in October or September, booked 66 days in advance, depart on a Tuesday or Wednesday and return on a Thursday

Find flight deals from St. Louis to Seattle

Cheapest flights from St. Louis to Seattle
Explore the most affordable flight options available from St. Louis to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on November 12, 2025.

This Kiwi.com deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/239:54 pmSTL - SEA
1 stop17h 28mFrontier
Fri 11/282:17 pmSEA - STL
2 stops17h 45mFrontier
Deal found 11/11$192
This Expedia deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/57:43 pmSTL - SEA
1 stop18h 10mMultiple Airlines
Sun 12/76:05 pmSEA - STL
Nonstop3h 54mMultiple Airlines
Deal found 11/11$193
This Kiwi.com deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/43:30 pmSTL - SEA
2 stops22h 23mFrontier
Sun 12/146:18 pmSEA - STL
1 stop15h 54mFrontier
Deal found 11/11$195
This Kiwi.com deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/2110:10 pmSTL - SEA
1 stop14h 01mFrontier
Sat 12/271:31 pmSEA - STL
2 stops29h 54mFrontier
Deal found 11/11$197
This Kiwi.com deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/267:43 pmSTL - SEA
1 stop18h 13mFrontier
Sun 11/309:53 pmSEA - STL
2 stops46h 40mFrontier
Deal found 11/11$198
This Kiwi.com deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/57:43 pmSTL - SEA
1 stop18h 10mFrontier
Thu 12/1112:48 pmSEA - STL
2 stops18h 11mFrontier
Deal found 11/11$200
This Expedia deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/2110:10 pmSTL - SEA
1 stop14h 01mMultiple Airlines
Mon 12/296:05 pmSEA - STL
Nonstop3h 54mMultiple Airlines
Deal found 11/11$201
This Kiwi.com deal was found by Cheapflights users on 11/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/137:43 pmSTL - SEA
2 stops16h 13mFrontier
Sun 12/146:18 pmSEA - STL
1 stop15h 54mFrontier
Deal found 11/12$202
This Kiwi.com deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/79:14 pmSTL - SEA
1 stop14h 52mFrontier
Fri 12/123:40 pmSEA - STL
1 stop16h 34mFrontier
Deal found 11/11$205
This Kiwi.com deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/2112:01 pmSTL - SEA
1 stop27h 21mFrontier
Wed 11/2612:51 pmSEA - STL
1 stop28h 07mFrontier
Deal found 11/11$206
This Delta deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/96:30 amSTL - SEA
1 stop8h 27mDelta
Tue 12/166:00 amSEA - STL
1 stop8h 49mDelta
Deal found 11/11$209

Cheap flight deals from St. Louis to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Seattle (SEA). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated November 12, 2025.

Most accurate provider

CheapOair
3 stars

Most trusted provider

CheapOair
3 stars

Round-trip from

$192
(Kiwi.com)

One-way from

$59
(Trip.com)

Popular in

July

Cheapest in

October

Average price

$306

Good round-trip deal

$348 or less

Good one-way deal

$267 or less
Provider with most accurate pricing for Lambert-St Louis-Seattle/Tacoma Intl flight deals.
Search Deals
Provider most trusted by Cheapflights users for Lambert-St Louis-Seattle/Tacoma Intl flights.
Search Deals
From Lambert-St Louis to Seattle/Tacoma Intl
Search Deals
One-way flight from Lambert-St Louis to Seattle/Tacoma Intl
Search Deals
Highest demand for flights based on searches. 12% potential increase in price ($48 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($9 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in November 2025
Search Deals
Price to beat on a round-trip flight from Lambert-St Louis to Seattle/Tacoma Intl.
Search Deals
Price to beat on a one-way flight from Lambert-St Louis to Seattle/Tacoma Intl.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from St. Louis to Seattle that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated November 12, 2025.
Use the filters below to find and compare flights from St. Louis to Seattle that are best for you.

Fly from

St. Louis

Fly to

Seattle

Route

Depart

Return

Price

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 12/9

5:25 pm-10:55 pm

1 stop7h 30m

Seattle/Tacoma Intl

Tue 12/16

8:10 am-7:45 pm

2 stops9h 35m

$214

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sun 12/7

7:00 am-9:40 am

Nonstop4h 40m

Seattle/Tacoma Intl

Wed 12/10

8:34 am-2:27 pm

Nonstop3h 53m

$227

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 12/9

7:00 am-9:40 am

Nonstop4h 40m

Seattle/Tacoma Intl

Thu 12/11

6:05 pm-11:59 pm

Nonstop3h 54m

$227

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 12/9

2:25 pm-10:55 pm

2 stops10h 30m

Seattle/Tacoma Intl

Mon 12/15

5:15 am-5:15 pm

2 stops10h 00m

$237

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Thu 12/4

3:23 pm-5:59 pm

Nonstop4h 36m

Seattle/Tacoma Intl

Sun 12/14

8:34 am-2:27 pm

Nonstop3h 53m

$237

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sun 12/7

7:00 am-9:40 am

Nonstop4h 40m

Seattle/Tacoma Intl

Sun 12/14

6:05 pm-11:59 pm

Nonstop3h 54m

$237

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Wed 11/26

7:47 pm-12:11 am

1 stop6h 24m

Seattle/Tacoma Intl

Wed 12/3

5:00 pm-1:01 am

1 stop6h 01m

$253

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 12/9

7:00 am-9:40 am

Nonstop4h 40m

Seattle/Tacoma Intl

Tue 12/16

8:34 am-2:27 pm

Nonstop3h 53m

$283

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 12/2

1:50 pm-10:30 pm

2 stops10h 40m

Seattle/Tacoma Intl

Thu 12/4

5:15 am-5:15 pm

2 stops10h 00m

$312

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sun 1/11

6:45 am-3:44 pm

1 stop10h 59m

Seattle/Tacoma Intl

Sat 1/17

5:00 am-4:03 pm

2 stops9h 03m

$314

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/9

Showing 1-10 of 20 results
1
2

Compare providers for flights from St. Louis to Seattle

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from St. Louis to Seattle in November.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice Accuracy3 starsTrust Score*3 stars
CheapflightsfaresPrice Accuracy3 starsTrust Score*2 stars
CheapOairPrice Accuracy3 starsTrust Score*3 stars
CheapfaremartPrice Accuracy-Trust Score*1 star
JustAirTicketPrice Accuracy-Trust Score*1 star

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on St. Louis-Seattle flights, users find the pricing of CheapOair to be most consistent on Cheapflights vs. CheapOair Users can find the same prices on St. Louis-Seattle flight deals on Cheapflights vs. CheapOair >95% of the time. Price accuracy is based on data collected from St. Louis-Seattle flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on St. Louis-Seattle flights, Cheapflights users trust CheapOair the most. CheapOair has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Seattle flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from St. Louis to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from St. Louis with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from St. Louis to Seattle

How far ahead should I book a flight from St. Louis to Seattle?

Use this chart to determine the optimal time to book a round-trip flight from St. Louis to Seattle. Price data was last updated on November 7, 2025.

The best time to book flights from St. Louis to Seattle is 66 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

What is the cheapest month to book a flight from St. Louis to Seattle?

Currently, April is the cheapest month in which you can book a flight from St. Louis to Seattle (average of $138). Flying from St. Louis to Seattle in February is currently the most expensive (average of $216). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from STL to SEA?

Find hourly flight availability from St. Louis to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated November 12, 2025.

Unlike at noon, when flights are generally more expensive, you can save up to 14% on flights from St. Louis to Seattle by exploring options for tickets in the afternoon.

What is the cheapest day to fly from St. Louis to Seattle?

Use this chart to determine the cheapest time to fly round-trip from St. Louis to Seattle. Price data was last updated on November 2, 2025.

Travelers seeking maximum savings on their St. Louis to Seattle flight should consider departing on Monday evenings when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

The best insider tips for St. Louis to Seattle flights

Snippets provided in this section are AI-generated based on a summarization of Cheapflights-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
Cheapflights partnered with top experts to bring you the best recommendations for your St. Louis to Seattle trip
Airports
STL

Security lines at STL are usually quick, averaging 5 to 10 minutes during off-peak times. Check real-time wait times online before heading to the airport.

Read more about STLby Taryn White
SEA

Take the Link light rail from SEA to downtown Seattle. It's affordable, runs every 10 minutes, and takes less than 40 minutes.

Read more about SEAby Brandon Schultz
Our travel experts
Taryn White

Taryn White

Expert on STL

Taryn White

Taryn White

Taryn White is a freelance travel writer, digital creator, and travel advisor who has visited nearly 100 countries and all 50 states. She’s familiar with many airports and enjoys beach hopping, boutique hotels, spa experiences, and exploring local culture. Her work has appeared in Travel + Leisure, Condé Nast Traveler, National Geographic, Smithsonian Magazine, AFAR, and more.

Read more
Brandon Schultz

Brandon Schultz

Expert on SEA

Brandon Schultz

Brandon Schultz

Brandon Schultz is an award-winning food and travel writer based in New York City. His work has appeared in Forbes, AAA, Thrillist, Travel + Leisure, and The Daily Meal, among many others, and he is the author of 6 books, including 3 cookbooks.

Read more

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Seattle. Reviews last updated November 12, 2025.
Read through reviews of airlines operating flights from St. Louis to Seattle, such as Alaska Airlines, Southwest, and Delta. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
11,275 reviews

Entertainment

7.0

Food

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why
Alaska Airlines
8.0
Very good
11,275 reviews
Alaska Airlines
8.0
Very good
11,275 reviews

Entertainment

7.0

Food

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why
Southwest
8.0
Very good
4,235 reviews
Alaska Airlines
8.0
Very good
11,275 reviews

Entertainment

7.0

Food

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why
Delta
7.9
Good
8,008 reviews
Alaska Airlines
8.0
Very good
11,275 reviews

Entertainment

7.0

Food

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why
Hawaiian Airlines
7.8
Good
2,809 reviews
Alaska Airlines
8.0
Very good
11,275 reviews

Entertainment

7.0

Food

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why
American Airlines
7.2
Good
11,050 reviews
Alaska Airlines
8.0
Very good
11,275 reviews

Entertainment

7.0

Food

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why

Related info for your journey

Find useful and relevant information for your journey from St. Louis to Seattle. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airports do I use to fly from St. Louis to Seattle?

    Booking a flight from Lambert-St Louis (STL) to Seattle/Tacoma Intl (SEA) is your only option if you wish to fly from St. Louis to Seattle. On a typical day, there are 7 flights from Lambert-St Louis to Seattle/Tacoma Intl, all of which are around 4h 27m for a nonstop flight. You can also purchase a plane ticket from 7 airlines when you book a flight from Lambert-St Louis to Seattle.

  • How popular is this St. Louis to Seattle flight route?

    Within the past month, 53 users have taken a look at flights from Lambert-St Louis to Seattle/Tacoma Intl.

  • How long is the flight from St. Louis to Seattle?

    Airlines like Southwest and Alaska Airlines fly from St. Louis to Seattle in about 4h 40m. The time it takes to get you to your destination can typically vary by up to 2h 50m. There are 1704 mi between St. Louis and Seattle. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

  • What are the cheapest airlines flying from St. Louis to Seattle round-trip?

    Currently priced at $94, Delta will fly you from St. Louis to Seattle and back. In addition to Delta, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from Frontier and Southwest - these airlines can fly you to your destination from $120 and $176, respectively. You may be able to fly from St. Louis to Seattle for 73% less than the average price by searching for these airlines.

  • What are the most reliable airlines from St. Louis to Seattle?

    The top 3 most reliable airlines when flying from St. Louis to Seattle are Qatar Airways (95%), Japan Airlines (95%) and American Airlines (86%).

  • What are the cheapest flights from St. Louis to Seattle?

    Looking for the cheapest flight from St. Louis to Seattle? While on average our users pay $1,026, our data indicates the cheapest price to be $165. The most popular route (Lambert-St Louis - Seattle/Tacoma Intl), is priced around $157.

  • Can I find deals for flights from St. Louis to Seattle that include hotel bookings?

    Yes. In addition to deals on St. Louis to Seattle flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from St. Louis to Seattle?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Seattle.

  • Can I find deals for business class flights from St. Louis to Seattle?

    Yes. Cheapflights offers flight deals from St. Louis to Seattle by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from St. Louis to Seattle?

    Currently, April is the cheapest month in which you can book a flight from St. Louis to Seattle (average of $138). Flying from St. Louis to Seattle in February is currently the most expensive (average of $216). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
SeaTac
Tacoma
Tukwila
Lakewood
Olympia
Ocean Shores
Lynnwood
Edmonds
Leavenworth
Renton
Kirkland
Lacey
Kent
Cle Elum
Marysville
Puyallup
Federal Way
Fife
Issaquah
Aberdeen

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Top 7 airlines flying from St. Louis to Seattle

Discover the top 7 airlines that operate flights from St. Louis to Seattle. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated November 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$94Average$237FlexibilityNo cancel feeOn-timeN/A
FrontierCheapest$120Average$244FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$176Average$377FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$188Average$407FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$216Average$352FlexibilityNo cancel feeOn-time69%
Hawaiian AirlinesCheapest$237Average$380FlexibilityNo cancel feeOn-time85%
Alaska AirlinesCheapest$240Average$390FlexibilityNo cancel feeOn-time75%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.