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

Popular airlines from Seattle-Tacoma International Airport (SEA) to St. Louis, MO (CPS-St. Louis Downtown)

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Alternative airports near St. Louis

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Lambert-St. Louis Intl. STL. Cheapest option available. Average driving time to city center is 20 minutes. Flights from $231
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $231

Frequently asked questions

How much does a flight from Seattle - Tacoma Intl. Airport (SEA) to St. Louis Downtown Airport (CPS) cost?
Grab a cheap one-way flight or cheap return flight from Seattle - Tacoma Intl. Airport (SEA) to St. Louis Downtown Airport (CPS) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to find our cheapest flight deals on this route.
What is the cheapest month to fly from Seattle - Tacoma Intl. Airport (SEA) to St. Louis Downtown Airport (CPS)?
The cheapest month to fly from SEA to CPS is , when there's less demand. Off-peak season is typically when better flight deals are available between these airports.
What is the cheapest airline that flies from Seattle - Tacoma Intl. Airport (SEA) to St. Louis Downtown Airport (CPS)?
Use the filters on Expedia to compare airlines and find the cheapest carrier that'll take you from SEA to CPS. Then, sort your results by "Price (lowest to highest)" to snap up a good deal.
How many flights per day from Seattle - Tacoma Intl. Airport (SEA) to St. Louis Downtown Airport (CPS)?
You'll need to take a flight with a layover if you're traveling from Seattle - Tacoma Intl. Airport (SEA) to St. Louis Downtown Airport (CPS). Direct flights don't operate daily on this route. However, simply filter your search to include one or more stops to discover an option that works for you.
What day of the week has the most flights from SEA to CPS?
Generally you'll find the largest variety of flight choices on a Friday. Tuesdays tend to be the quietest.* However, this can change depending on the airline, season and other factors.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Seattle - Tacoma Intl. Airport (SEA) to St. Louis Downtown Airport (CPS)?
To touch down at St. Louis Downtown Airport (CPS) on schedule, select a flight that leaves Seattle - Tacoma Intl. Airport (SEA) before 3 PM. The chance of cancellations is 22% higher, on average, for departures after this time.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports do you fly into for East St. Louis from Seattle - Tacoma Intl. Airport (SEA)?
Lambert-St. Louis Intl. Airport (STL) is the only airport in East St. Louis with direct flights from Seattle - Tacoma Intl. Airport (SEA). Browse your options and discover cheap fares on Expedia.
Is it cheaper to buy a plane ticket from Seattle - Tacoma Intl. Airport (SEA) to St. Louis Downtown Airport (CPS) last-minute?
Holding off until just before your trip to book your flight from SEA to CPS often results in higher prices. Although you may find some last-minute offers, they aren't always guaranteed. Be flexible with your itinerary for a better chance of scoring a bargain.
Is it cheaper to book a SEA to CPS flight and hotel package?
You'll typically save money by securing a SEA to CPS flight and hotel package compared to booking separately. In fact, you could save hundreds of dollars by bundling with Expedia. And it's simple to manage everything in one convenient place. After selecting your ideal accommodations and flights, you can add extras like activities, car rentals and tours.
Can I cancel or change the date of my flight from Seattle - Tacoma Intl. Airport (SEA) to St. Louis Downtown Airport (CPS)?
Typically, you're able to reschedule or cancel your SEA to CPS flight. However, there may be additional charges, especially if you booked over 24 hours ago. Check your itinerary for the airline's fees and guidelines on flight changes, or if you'd like more information, go to our Customer Service portal.

Travel information

Origin airport
Seattle - Tacoma Intl.
Destination airport
St. Louis Downtown
Distance
1720 mi

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Seattle to St. Louis Flights

The cheapest times to fly from Seattle to St. Louis

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Seattle to St. Louis are during the month of . You can find some of the cheapest flights from Seattle to St. Louis with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Seattle to St. Louis

Sunday is one of the best days to book for cheap flights from Seattle to St. Louis: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Seattle to St. Louis

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Seattle to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Seattle to St. Louis flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Seattle to St. Louis airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Seattle to St. Louis Flights

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