C$ 144 Find Cheap Flights from Seattle to St. Louis – Compare and Save

Among airlines operating Seattle to St. Louis flights:

• Alaska Airlines: offers extra legroom; offers free seat selection
• American Airlines: offers free seat selection
• Southwest: offers free seat selection

Extra legroom and free seat selection availability depends on fare class and route.

2 airlines operate flights between Seattle and St. Louis. The airlines offering direct flights on this route include:

• Alaska Airlines
• Southwest

Flights from Seattle to St. Louis usually depart from Seattle/Tacoma Intl (SEA) and arrive at Lambert-St Louis (STL).

Here are some options for this route, based on selected ticket types and cabin classes:

• Alaska Airlines: a carry-on bag and a checked bag in Economy Class
• American Airlines: a carry-on bag and a checked bag in First Class
• Southwest: a cabin bag in Economy Class class

Bag allowance can vary by ticket type, cabin class, route, and airline, so travellers should check the fare details before booking.

Two cabin classes are available on flights from Seattle to St. Louis:

• Economy Class
• First Class

On this route, layover flights are cheaper than direct options on average. Layover fares average C$ 338 round-trip via Dallas/Fort Worth (DFW), compared to C$ 631 for direct.

There is no standard. Checked bag policies vary by airline on this route. Most carriers charge C$ 56–C$ 139 for the first checked bag in economy. Premium fares and elite status bookings typically include a free checked bag.

The Boeing 737 family is used most often on this route, operated mainly by American Airlines. Other aircraft seen on the route include Boeing 737 MAX 8 variants.

One-stop flights from Seattle to St. Louis most commonly connect through:

• Denver Intl (DEN) – 46% of one-stop connections
• Salt Lake City (SLC) – 21% of one-stop connections
• Chicago O'Hare Intl (ORD) – 11% of one-stop connections
• Dallas/Fort Worth (DFW) – 8% of one-stop connections

Denver Intl (DEN) handles the largest share of one-stop connections on this route.

Yes. Being flexible with your travel dates can save you up to 43% on the Seattle to St. Louis route. Tuesday is the cheapest departure day at C$ 502 round-trip on average, while Sunday is the most expensive at C$ 871, a difference of C$ 370. KAYAK's flexible dates feature shows options up to 3 days before and after your selected dates, making it easier to compare nearby fares.

Morning is the busiest departure period on Seattle to St. Louis flights, with 50% leaving in that window. Evening departures account for 50%, Afternoon flights for 0%, and Night flights for 0%.

Some of the most popular sights in St. Louis are Forest Park Hotel, Hyatt Regency St Louis At The Arch, and America's Center Convention Complex. These are among the most viewed places in St. Louis on KAYAK.

These are the earliest and latest flight times available from Seattle to St. Louis:

• Earliest: departs at 8:03 am and lands at 12:02 pm
• Latest: departs at 6:08 pm and lands at 10:07 pm.

The flight takes about 3h 59m.

Last-minute fares on this route – booked within 2 weeks of departure – run 47% above the route average of C$ 594. Book 15 weeks before departure for the lowest fares.

A direct flight from Seattle to St. Louis takes 3h 59m, covering 4,413 km.

No, a passport is not required for this domestic route, but you will need a real ID-compliant driver's license, a state ID, or another TSA-accepted form of identification.

One-way fares from Seattle to St. Louis are currently lower than usual. Average one-way flight prices are about C$ 160, which is 56% below the typical average for this route.

Flying via Salt Lake City (SLC) gives the shortest average 1-stop total travel time at 6h 33m, compared with 7h 10m via Minneapolis St Paul (MSP) and 7h 25m via Dallas/Fort Worth (DFW).

St. Louis is 2 hours ahead of Seattle (Central Time vs Pacific Time). Plan for the time shift when scheduling connections or first-day activities.

Lambert-St Louis Airport (STL) hosts 5 major car rental companies, with daily rates starting from around C$ 42 for economy cars. Top options include:
• Hertz
• Budget
• Alamo
• Enterprise Rent-A-Car
• Payless

Round-trip flights from Seattle to St. Louis range from C$ 410 to C$ 831, with an average of C$ 594 over the past 12 months. Anything below C$ 410 counts as a good deal.

Alaska Airlines is the only airline on the Seattle to St. Louis route offering in-flight Wi-Fi. Pricing depends on fare class.