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St. Louis

$171+ Cheap flights from Ottawa (YOW) to St. Louis (STL)

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 5/16. Fares are subject to change and may not be available on all flights or dates of travel.
YOW — STL
May 2 — May 91
Sat 5/2
Sat 5/9
1 adult, Economy
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Cheap flight deals from Ottawa to St. Louis

Cheapest flights from Ottawa to St. Louis
Explore the most affordable flight options available from Ottawa to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 2, 2026.

This Trip.com deal was found by Cheapflights users on 3/30. 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.
Mon 5/183:00 pm
YOW
-
STL
1 stop6h 25m
Air Canada
Sun 5/247:05 am
STL
-
YOW
1 stop5h 00m
Air Canada
Deal found 3/30$265
This Air Canada deal was found by Cheapflights users on 4/1. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/162:35 pm
YOW
-
STL
1 stop6h 50m
Air Canada
Sat 5/237:05 am
STL
-
YOW
1 stop5h 00m
Air Canada
Deal found 4/1$282
This United Airlines deal was found by Cheapflights users on 3/30. 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.
Wed 6/310:44 am
YOW
-
STL
1 stop11h 32m
United Airlines
Sat 6/69:23 am
STL
-
YOW
1 stop11h 12m
United Airlines
Deal found 3/30$288
This Air Canada deal was found by Cheapflights users on 3/30. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/39:55 am
YOW
-
STL
2 stops6h 51m
Air Canada
Sat 6/61:13 pm
STL
-
YOW
1 stop7h 22m
Air Canada
Deal found 3/30$341
This United Airlines deal was found by Cheapflights users on 4/1. 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.
Sat 5/1612:00 pm
YOW
-
STL
2 stops10h 13m
United Airlines
Sat 5/237:05 am
STL
-
YOW
1 stop5h 00m
United Airlines
Deal found 4/1$357
This United Airlines deal was found by Cheapflights users on 3/28. 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.
Sat 9/196:25 am
YOW
-
STL
1 stop10h 13m
United Airlines
Mon 9/218:30 pm
STL
-
YOW
2 stops16h 40m
United Airlines
Deal found 3/28$359
This United Airlines deal was found by Cheapflights users on 4/1. 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 4/245:00 am
YOW
-
STL
2 stops17h 13m
United Airlines
Wed 4/296:30 am
STL
-
YOW
2 stops6h 57m
United Airlines
Deal found 4/1$386

Find flight deals from Ottawa to St. Louis

Discover tips and strategies to find the most affordable flight options for your journey from Ottawa (YOW) 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 April 2, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$265
(Trip.com)

One-way from

$171
(Air Canada)

Popular in

April

Cheapest in

January

Average price

$836
Provider with most accurate pricing for Ottawa-Lambert-St Louis flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ottawa-Lambert-St Louis flights.
Search Deals
From Ottawa to Lambert-St Louis
Search Deals
One-way flight from Ottawa to Lambert-St Louis
Search Deals
Highest demand for flights based on searches. 19% potential increase in price ($146 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($24 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in April 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ottawa to St. Louis 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 April 2, 2026.
Use the filters below to find and compare flights from Ottawa to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Fri 4/24

7:30 pm-10:31 am

1 stop16h 01m

Lambert-St Louis

Wed 4/29

11:15 am-5:07 pm

1 stop4h 52m

$288

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 6/3

10:44 am-9:16 pm

1 stop11h 32m

Lambert-St Louis

Sat 6/6

9:23 am-9:35 pm

1 stop11h 12m

$288
Quickest round-trip

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 6/3

9:55 am-3:46 pm

2 stops6h 51m

Lambert-St Louis

Sat 6/6

1:13 pm-9:35 pm

1 stop7h 22m

$341
Cheapest one-way
Quickest one-way

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 5/16

2:35 pm-8:25 pm

1 stop6h 50m

$171

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 5/16

10:25 am-10:45 pm

2 stops13h 20m

$200

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 5/16

7:15 pm-8:55 am

3 stops38h 40m

$368

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/1

Sorted by cheapest first
  • Most accurate provider: When it comes to deals on Ottawa-St. Louis flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ottawa-St. Louis flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ottawa-St. Louis flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ottawa-St. Louis flights, Cheapflights users trust FlightHub the most. FlightHub 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 Ottawa-St. Louis 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 Ottawa to St. Louis

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

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

Currently, May is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of $269). Flying from Ottawa to St. Louis in August is currently the most expensive (average of $582). 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.

How much does it cost to fly round-trip from Ottawa to St. Louis?

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 April 2, 2026.
Read through reviews of airlines operating flights from Ottawa to St. Louis, such as Air Canada. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Air Canada
7.1
Good
10,880 reviews

Overall

7.1

Comfort

7.1

Crew

7.8

Food

6.3

Boarding

7.3

Entertainment

6.8

Reviews

1 / 20
4.0
Okay

Sugith,Jan 2026

YSB - YYZ

Left 2 hours late. Stuck on plane for an hour after boarding before take off.
Air Canada
7.1
Good
10,880 reviews
Air Canada
7.1
Good
10,880 reviews

Overall

7.1

Comfort

7.1

Crew

7.8

Food

6.3

Boarding

7.3

Entertainment

6.8

Reviews

1 / 20
4.0
Okay

Sugith,Jan 2026

YSB - YYZ

Left 2 hours late. Stuck on plane for an hour after boarding before take off.

Related info for your journey

Find useful and relevant information for your journey from Ottawa 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 long is the flight from Ottawa to St. Louis?

    Departing from Ottawa to St. Louis will take you 16h 01m. The distance from Ottawa to St. Louis is about 878 mi.

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

    Our cheapest airline available from Ottawa to St. Louis is Air Canada. Our recent data shows that you can find tickets from as low as $343 on this airline. You may be able to fly from Ottawa to St. Louis for 43% less than the average price by searching for this airline.

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

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

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

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

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

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

    Currently, May is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of $269). Flying from Ottawa to St. Louis in August is currently the most expensive (average of $582). 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
Edwardsville
O'Fallon
Fenton
Swansea
Fairview Heights
Maryland Heights
Collinsville
Eureka
Wentzville
Glencoe
Chesterfield
Alton
Farmington
Festus

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Ottawa to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.
Pearson Intl to St. Louis flights
Pierre Elliott Trudeau Intl to St. Louis flights
Ottawa to Kansas City flights

Top airline flying from Ottawa to St. Louis

Discover the top airline that operate flights from Ottawa 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 2,558,603 searches. Data last updated April 2, 2026.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$343Average$641FlexibilityNo cancel feeOn-time67%

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