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$66+ 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 2/28. Fares are subject to change and may not be available on all flights or dates of travel.
STL — SEA
Feb 20 — Feb 271
Fri 2/20
Fri 2/27
1 adult, Economy
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Find cheap flights from St. Louis to Seattle with Cheapflights

1. Tell us where you want to go

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

Cheap 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 January 21, 2026.

This Kiwi.com deal was found by Cheapflights users on 1/21. 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 3/45:18 pm
STL
-
SEA
2 stops16h 55m
Frontier
Sun 3/812:24 pm
SEA
-
STL
1 stop19h 25m
Frontier
Deal found 1/21$174
This Kiwi.com deal was found by Cheapflights users on 1/20. 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 2/282:51 pm
STL
-
SEA
1 stop22h 04m
Frontier
Tue 3/37:33 pm
SEA
-
STL
2 stops24h 54m
Frontier
Deal found 1/20$176
This Delta deal was found by Cheapflights users on 1/21. 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 4/216:45 pm
STL
-
SEA
1 stop7h 14m
Delta
Sat 4/255:35 am
SEA
-
STL
1 stop7h 05m
Delta
Deal found 1/21$177
This Kiwi.com deal was found by Cheapflights users on 1/20. 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 2/131:59 pm
STL
-
SEA
1 stop24h 02m
Frontier
Thu 2/191:16 pm
SEA
-
STL
1 stop21h 53m
Frontier
Deal found 1/20$183
This Kiwi.com deal was found by Cheapflights users on 1/21. 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 2/146:41 pm
STL
-
SEA
2 stops18h 14m
Frontier
Fri 2/2012:00 pm
SEA
-
STL
1 stop23h 56m
Frontier
Deal found 1/21$186
This Kiwi.com deal was found by Cheapflights users on 1/20. 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 2/142:51 pm
STL
-
SEA
1 stop22h 04m
Frontier
Sun 2/229:23 pm
SEA
-
STL
2 stops20h 39m
Frontier
Deal found 1/20$188
This Trip.com deal was found by Cheapflights users on 1/20. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 2/142:47 pm
STL
-
SEA
Nonstop4h 39m
Multiple Airlines
Sat 2/217:55 am
SEA
-
STL
Nonstop3h 56m
Multiple Airlines
Deal found 1/20$189
This WAYA deal was found by Cheapflights users on 1/21. 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 WAYA is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 2/282:51 pm
STL
-
SEA
1 stop7h 35m
Multiple Airlines
Wed 3/47:55 am
SEA
-
STL
Nonstop3h 56m
Multiple Airlines
Deal found 1/21$193
This Kiwi.com deal was found by Cheapflights users on 1/20. 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.
Mon 2/99:45 pm
STL
-
SEA
1 stop15h 09m
Frontier
Tue 2/106:30 pm
SEA
-
STL
2 stops17h 28m
Frontier
Deal found 1/20$195
This Alaska Airlines deal was found by Cheapflights users on 1/19. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/213:50 pm
STL
-
SEA
Nonstop4h 33m
Alaska Airlines
Sat 5/25:57 pm
SEA
-
STL
Nonstop4h 02m
Alaska Airlines
Deal found 1/19$197
This Delta deal was found by Cheapflights users on 1/20. 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.
Wed 3/116:12 pm
STL
-
SEA
1 stop7h 49m
Delta
Mon 3/161:32 pm
SEA
-
STL
1 stop8h 49m
Delta
Deal found 1/20$198
This Kiwi.com deal was found by Cheapflights users on 1/20. 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.
Mon 2/99:45 pm
STL
-
SEA
1 stop15h 09m
Frontier
Sun 2/229:23 pm
SEA
-
STL
2 stops20h 39m
Frontier
Deal found 1/20$199

Find 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 January 21, 2026.

Most accurate provider

CheapOair
3 stars

Most trusted provider

CheapOair
3 stars

Round-trip from

$174
(Kiwi.com)

One-way from

$66
(Kiwi.com)

Popular in

July

Cheapest in

October

Average price

$359

Good round-trip deal

$327 or less

Good one-way deal

$214 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. 14% potential increase in price ($58 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 January 2026
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 January 21, 2026.
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 4/21

1:40 pm-9:49 pm

1 stop10h 09m

Seattle/Tacoma Intl

Sat 5/2

8:20 am-5:02 pm

1 stop6h 42m

$177

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Thu 2/26

6:40 pm-12:09 am

1 stop7h 29m

Seattle/Tacoma Intl

Mon 3/2

11:15 pm-9:32 am

1 stop8h 17m

$177

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Fri 5/1

6:45 pm-11:59 pm

1 stop7h 14m

Seattle/Tacoma Intl

Sun 5/3

11:59 pm-8:30 am

1 stop6h 31m

$177

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 4/21

7:00 am-9:35 am

Nonstop4h 35m

Seattle/Tacoma Intl

Sat 5/2

9:39 am-3:50 pm

Nonstop4h 11m

$197

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Fri 3/20

5:25 pm-11:40 pm

1 stop8h 15m

Seattle/Tacoma Intl

Thu 3/26

1:32 pm-12:21 am

1 stop8h 49m

$198

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 2/10

2:50 pm-5:25 pm

Nonstop4h 35m

Seattle/Tacoma Intl

Thu 2/12

6:07 pm-11:59 pm

Nonstop3h 52m

$207

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 2/10

2:50 pm-5:25 pm

Nonstop4h 35m

Seattle/Tacoma Intl

Sun 2/22

6:07 pm-11:59 pm

Nonstop3h 52m

$207

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Thu 2/19

7:00 am-9:42 am

Nonstop4h 42m

Seattle/Tacoma Intl

Thu 2/26

7:55 am-1:51 pm

Nonstop3h 56m

$217

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Thu 2/26

2:47 pm-5:26 pm

Nonstop4h 39m

Seattle/Tacoma Intl

Mon 3/2

6:07 pm-11:59 pm

Nonstop3h 52m

$217

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 2/10

6:10 am-10:55 am

1 stop6h 45m

Seattle/Tacoma Intl

Sun 2/22

6:10 am-4:45 pm

1 stop8h 35m

$237

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/21

Showing 1-10 of 23 results
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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 January.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
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 January 16, 2026.

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 $133). Flying from St. Louis to Seattle in August is currently the most expensive (average of $222). 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 January 21, 2026.

Unlike in the morning, when flights are generally more expensive, you can save up to 11% 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 January 17, 2026.

Travelers seeking maximum savings on their St. Louis to Seattle flight should consider departing on Tuesday afternoons when fares are most often at their lowest. Tuesday 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

AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your St. Louis to Seattle trip
Our travel experts
Taryn White

Taryn White

Expert on STL

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 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 January 21, 2026.
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
11,775 reviews

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Dec 2025

SJC - SEA

The flight was great. Don’t have to make it better. Everything was OK.
Alaska Airlines
8.0
Very good
11,775 reviews
Alaska Airlines
8.0
Very good
11,775 reviews

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Dec 2025

SJC - SEA

The flight was great. Don’t have to make it better. Everything was OK.
Southwest
8.0
Very good
4,266 reviews
Alaska Airlines
8.0
Very good
11,775 reviews

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Dec 2025

SJC - SEA

The flight was great. Don’t have to make it better. Everything was OK.
Delta
7.9
Good
8,088 reviews
Alaska Airlines
8.0
Very good
11,775 reviews

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Dec 2025

SJC - SEA

The flight was great. Don’t have to make it better. Everything was OK.
Hawaiian Airlines
7.8
Good
2,829 reviews
Alaska Airlines
8.0
Very good
11,775 reviews

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Dec 2025

SJC - SEA

The flight was great. Don’t have to make it better. Everything was OK.
American Airlines
7.2
Good
11,173 reviews
Alaska Airlines
8.0
Very good
11,775 reviews

Overall

8.0

Comfort

7.8

Crew

8.5

Entertainment

7.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Dec 2025

SJC - SEA

The flight was great. Don’t have to make it better. Everything was OK.

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 3 flights from Lambert-St Louis to Seattle/Tacoma Intl, all of which are around 4h 15m 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, 45 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 Delta and Alaska Airlines fly from St. Louis to Seattle in about 4h 35m. The time it takes to get you to your destination can typically vary by up to 5h 34m. 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 $100 and $176, respectively. You may be able to fly from St. Louis to Seattle for 72% less than the average price by searching for these airlines.

  • What are the cheapest airlines to fly from St. Louis to Seattle one-way?

    The cheapest airlines for a one-way flight from St. Louis to Seattle are Frontier ($78), Southwest ($88), and American Airlines ($94).

  • 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 (87%), Alaska Airlines (83%) and Hawaiian Airlines (79%).

  • 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 $966, our data indicates the cheapest price to be $118. The most popular route (Lambert-St Louis - Seattle/Tacoma Intl), is priced around $153.

  • 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 $133). Flying from St. Louis to Seattle in August is currently the most expensive (average of $222). 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
Tacoma
SeaTac
Lakewood
Ocean Shores
Olympia
Lynnwood
Lacey
Edmonds
Renton
Puyallup
Kirkland
Kent
Tukwila
Fife
Aberdeen
Shoreline
Marysville
Centralia
Federal Way
Chehalis

Browse thousands of different options on Cheapflights for your next trip

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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 January 21, 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$94Average$225FlexibilityNo cancel feeOn-timeN/A
FrontierCheapest$100Average$194FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$176Average$380FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$179Average$353FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$188Average$398FlexibilityNo cancel feeOn-time71%
Hawaiian AirlinesCheapest$217Average$376FlexibilityNo cancel feeOn-time85%
Alaska AirlinesCheapest$237Average$380FlexibilityNo cancel feeOn-time75%

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