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Cheap flights from Seattle to St. Louis

SEA — STL
25 Apr — 2 May1
1 adult
1 adult, Economy, 0 bags

Find flight deals from Seattle to St. Louis

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to St. Louis (STL). 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 26 March 2026.

Popular in

December

Cheapest in

January

Average price

C$ 594

Good round-trip deal

C$ 383 or less
Highest demand for flights based on searches. 4% potential increase in price (C$ 35 potential increase over avg. RT price).
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Cheapest flight prices on average. 4% potential price decrease (C$ 29 potential savings vs. average RT price).
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Average for round-trip flights in March 2026
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Price to beat on a round-trip flight from Seattle/Tacoma Intl to Lambert-St Louis.
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Best time to book a flight from Seattle to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Seattle 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 Seattle to St. Louis

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

Use this chart to determine the optimal time to book a round-trip flight from Seattle to St. Louis. Price data was last updated on 13 March 2026.

The price you pay for your flight from Seattle to St. Louis may vary depending on when you book. For the best chance of a lower fare, look to book 67 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

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

Currently, January is the cheapest month in which you can book a flight from Seattle to St. Louis (average of C$ 210). Flying from Seattle to St. Louis in December is currently the most expensive (average of C$ 359). 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 SEA to STL?

Find hourly flight availability from Seattle to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 26 March 2026.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Seattle to St. Louis as you normally would.

Reviews of airlines servicing St. Louis

Get insights into the airlines that provide service to St. Louis. 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 St. Louis. Reviews last updated 26 March 2026.
Get a feel of what it's like to fly with Alaska Airlines from Seattle to St. Louis by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
7.9
Good
12,116 reviews
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Food

7.0

Overall

7.9

Entertainment

7.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.
Alaska Airlines
7.9
Good
12,116 reviews
Alaska Airlines
7.9
Good
12,116 reviews
Check prices

Food

7.0

Overall

7.9

Entertainment

7.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.

Related info for your journey

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

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

    Flights from Seattle/Tacoma Intl to Lambert-St Louis have been viewed 2 times in the past calendar month.

  • What is the cheapest airline to fly from Seattle to St. Louis round-trip?

    Flying on Alaska Airlines is currently your cheapest option to St. Louis, with prices starting at C$ 279. Alaska Airlines is 44% cheaper than the average price of flights available within the next 90 days to this destination.

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

    The top 3 most reliable airlines when flying from Seattle to St. Louis are Air Tahiti Nui (96%), Alaska Airlines (96%) and Hawaiian Airlines (96%).

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Seattle to St. Louis 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 Seattle to St. Louis?

    Currently, January is the cheapest month in which you can book a flight from Seattle to St. Louis (average of C$ 210). Flying from Seattle to St. Louis in December is currently the most expensive (average of C$ 359). 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

Travelling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
Chesterfield

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Top airline flying from Seattle to St. Louis

Discover the top airline that operate flights from Seattle to St. Louis. 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 629,999 searches. Data last updated 26 March 2026.
AirlineCheapestAverageFlexibilityOn-time
Alaska AirlinesCheapestC$ 279AverageC$ 431FlexibilityNo cancel feeOn-time75%
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Fly with Cheapflights

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How does Cheapflights help users find flights from Seattle to St. Louis?

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Why should you use Cheapflights to find cheap flight tickets from Seattle to St. Louis?

Cheapflights helps you find that perfect flight to St. Louis from Seattle by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

Can Cheapflights find flights from Seattle to St. Louis with no change fees?

Users can book flights with no change fees policies with our dedicated filters. Book flights from Seattle to St. Louis flexibly with Cheapflights today.

Can Cheapflights notify me if prices for flights from Seattle to St. Louis become cheaper?

Yes! Start tracking prices for Seattle to St. Louis flights today and get alerted whenever prices for these flights change. To access this feature, click the bell icon next to the flight deals above, which will prompt you for a valid email address to receive your alerts.

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