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$119+ 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 8/16. Fares are subject to change and may not be available on all flights or dates of travel.
STL — SEA
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
1 adult, Economy
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Cheapflights Tip: The best prices from Lambert-St Louis to Seattle/Tacoma Intl are usually found in September or October, booked 36 days in advance, depart on a Wednesday or Tuesday and return on a Thursday

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 June 12, 2025.

Round-trip from

$194
(Southwest)

One-way from

$119
(Delta)

Popular in

July

Cheapest in

September

Average price

$417

Good round-trip deal

$325 or less

Good one-way deal

$184 or less
From Lambert-St Louis to Seattle/Tacoma Intl
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One-way flight from Lambert-St Louis to Seattle/Tacoma Intl
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Highest demand for flights based on searches. 14% potential increase in price ($60 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($10 potential savings vs. average RT price).
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Average for round-trip flights in June 2025
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Price to beat on a round-trip flight from Lambert-St Louis to Seattle/Tacoma Intl.
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Price to beat on a one-way flight from Lambert-St Louis to Seattle/Tacoma Intl.
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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 June 12, 2025.

This Southwest deal was found by Cheapflights users on 6/9. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/74:20 pmSTL - SEA
1 stop9h 45mSouthwest
Tue 8/1210:45 pmSEA - STL
1 stop10h 05mSouthwest
Deal found 6/9$194
This Delta deal was found by Cheapflights users on 6/11. 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.
Thu 9/186:59 pmSTL - SEA
1 stop7h 10mDelta
Sat 9/275:45 pmSEA - STL
1 stop5h 37mDelta
Deal found 6/11$209
This American Airlines deal was found by Cheapflights users on 6/12. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/214:32 pmSTL - SEA
1 stop8h 23mAmerican Airlines
Mon 8/2512:45 amSEA - STL
1 stop10h 09mAmerican Airlines
Deal found 6/12$212
This United Airlines deal was found by Cheapflights users on 6/10. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/124:40 pmSTL - SEA
1 stop8h 19mUnited Airlines
Sat 9/207:00 amSEA - STL
1 stop6h 44mUnited Airlines
Deal found 6/10$218
This CheapOair deal was found by Cheapflights users on 6/10. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/127:52 pmSTL - SEA
1 stop6h 39mFrontier
Mon 9/158:34 pmSEA - STL
1 stop10h 33mFrontier
Deal found 6/10$239
This Hawaiian Airlines deal was found by Cheapflights users on 6/11. 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/183:24 pmSTL - SEA
Nonstop4h 26mHawaiian Airlines
Mon 9/811:34 amSEA - STL
Nonstop4h 00mHawaiian Airlines
Deal found 6/11$249
This Mytrip deal was found by Cheapflights users on 6/10. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/128:44 amSTL - SEA
2 stops33h 09mSpirit Airlines
Sat 9/204:58 pmSEA - STL
2 stops12h 51mSpirit Airlines
Deal found 6/10$316
This Orbitz deal was found by Cheapflights users on 6/10. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/103:24 pmSTL - SEA
Nonstop4h 26mMultiple Airlines
Sun 8/177:48 pmSEA - STL
1 stop11h 23mMultiple Airlines
Deal found 6/10$327
This Alaska Airlines deal was found by Cheapflights users on 6/10. 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.
Mon 7/77:32 pmSTL - SEA
Nonstop4h 28mAlaska Airlines
Mon 7/148:32 amSEA - STL
Nonstop3h 54mAlaska Airlines
Deal found 6/10$329

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 June 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

Thu 8/7

4:20 pm-12:05 am

1 stop9h 45m

Seattle/Tacoma Intl

Tue 8/12

10:45 pm-10:50 am

1 stop10h 05m

$194

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Thu 8/21

4:32 pm-10:55 pm

1 stop8h 23m

Seattle/Tacoma Intl

Mon 8/25

12:45 am-12:54 pm

1 stop10h 09m

$212

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sat 8/16

7:35 am-12:33 pm

1 stop6h 58m

Seattle/Tacoma Intl

Tue 8/19

5:30 am-1:29 pm

1 stop5h 59m

$213

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Wed 7/9

5:00 am-9:50 am

1 stop6h 50m

Seattle/Tacoma Intl

Wed 7/16

7:00 am-4:45 pm

1 stop7h 45m

$247

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Mon 8/18

3:24 pm-5:50 pm

Nonstop4h 26m

Seattle/Tacoma Intl

Mon 9/8

11:34 am-5:34 pm

Nonstop4h 00m

$249

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Mon 8/11

7:29 pm-12:34 am

1 stop7h 05m

Seattle/Tacoma Intl

Sun 8/17

7:48 pm-9:11 am

1 stop11h 23m

$260

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sun 7/13

10:47 am-4:25 pm

2 stops31h 38m

Seattle/Tacoma Intl

Wed 7/16

5:30 pm-9:52 am

2 stops14h 22m

$321

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sun 8/10

3:24 pm-5:50 pm

Nonstop4h 26m

Seattle/Tacoma Intl

Sun 8/17

7:48 pm-9:11 am

1 stop11h 23m

$327

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Mon 7/7

7:32 pm-10:00 pm

Nonstop4h 28m

Seattle/Tacoma Intl

Sat 7/19

6:06 pm-11:59 pm

Nonstop3h 53m

$329

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sun 7/6

6:36 am-8:05 am

1 stop27h 29m

Seattle/Tacoma Intl

Sun 7/13

8:12 am-7:31 pm

1 stop9h 19m

$425

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/11

Showing 1-10 of 20 results
1
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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

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 June 9, 2025.

The best time to book flights from St. Louis to Seattle is 36 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, January is the cheapest month in which you can book a flight from St. Louis to Seattle (average of $238). Flying from St. Louis to Seattle in July is currently the most expensive (average of $391). 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 June 12, 2025.

Unlike in the morning, when flights are generally more expensive, you can save up to 9% 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 June 8, 2025.

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

Weekly flight availability from St. Louis to Seattle

Explore weekly flight availability from St. Louis to Seattle. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated June 12, 2025.

The most flights from STL to SEA are scheduled on a Thursday (15 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (6 on average).

Rainfall in Seattle by month

Plan your trip to Seattle by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Seattle ranges from 0.7 - 6.6 inches per month. November is typically the wettest month, when rainfall can reach 6.6 in. July is typically the driest time to visit Seattle when rainfall is around 0.7 in.

Temperature in Seattle by month

Plan your trip to Seattle by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Seattle, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 66.2 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 41.0 F).

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 June 12, 2025.
See what other customers who have flown with Alaska Airlines, Southwest and Delta from St. Louis to Seattle have to say. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Boarding

8.1

Comfort

7.8

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Boarding

8.1

Comfort

7.8

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Southwest
8.0
Very good
4,287 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Boarding

8.1

Comfort

7.8

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Delta
8.0
Very good
7,946 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Boarding

8.1

Comfort

7.8

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Hawaiian Airlines
7.9
Good
2,494 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Boarding

8.1

Comfort

7.8

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
United Airlines
7.4
Good
8,790 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Food

7.1

Boarding

8.1

Comfort

7.8

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

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 10 flights from Lambert-St Louis to Seattle/Tacoma Intl, all of which are around 4h 19m 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, 40 users have taken a look at flights from Lambert-St Louis to Seattle/Tacoma Intl.

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

    Currently priced at $194, Southwest will fly you from St. Louis to Seattle and back. In addition to Southwest, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from American Airlines and Delta - these airlines can fly you to your destination from $212 and $213, respectively. You may be able to fly from St. Louis to Seattle for 46% 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 Delta ($119), Southwest ($120), and Hawaiian Airlines ($122).

  • 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 Japan Airlines (87%), Qatar Airways (86%) and American Airlines (80%).

  • 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 $1,118, our data indicates the cheapest price to be $124. The most popular route (Lambert-St Louis - Seattle/Tacoma Intl), is priced around $179.

  • 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, January is the cheapest month in which you can book a flight from St. Louis to Seattle (average of $238). Flying from St. Louis to Seattle in July is currently the most expensive (average of $391). 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 St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
SeaTac
Tukwila
Tacoma
Lakewood
Ocean Shores
Lacey
Leavenworth
Federal Way
Lynnwood
Olympia
Shoreline
Kent
Cle Elum
Centralia
Kirkland
Aberdeen
Renton
Shelton
Silverdale
Issaquah

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 June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$94Average$249FlexibilityNo cancel feeOn-timeN/A
FrontierCheapest$110Average$183FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$188Average$397FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$196Average$440FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$216Average$361FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$236Average$397FlexibilityNo cancel feeOn-time75%
Hawaiian AirlinesCheapest$241Average$415FlexibilityNo cancel feeOn-time85%

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