HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
St. Louis

$203+ 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 7/9. Fares are subject to change and may not be available on all flights or dates of travel.
YOW — STL
Jun 25 — Jul 21
Thu 6/25
Thu 7/2
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Ottawa to St. Louis with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

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 May 26, 2026.

This United Airlines deal was found by Cheapflights users on 5/22. 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.
Thu 6/116:25 am
YOW
-
STL
1 stop10h 21m
United Airlines
Mon 6/156:00 am
STL
-
YOW
1 stop15h 05m
United Airlines
Deal found 5/22$348
This United Airlines deal was found by Cheapflights users on 5/21. 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.
Thu 8/206:00 am
YOW
-
STL
2 stops10h 38m
United Airlines
Tue 9/18:00 am
STL
-
YOW
1 stop12h 35m
United Airlines
Deal found 5/21$349
This Air Canada deal was found by Cheapflights users on 5/24. 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.
Sun 6/217:00 am
YOW
-
STL
1 stop6h 21m
Air Canada
Sun 6/288:40 am
STL
-
YOW
1 stop5h 30m
Air Canada
Deal found 5/24$350
This Air Canada deal was found by Cheapflights users on 5/25. 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.
Tue 8/252:35 pm
YOW
-
STL
1 stop5h 07m
Air Canada
Sat 8/298:55 am
STL
-
YOW
1 stop5h 15m
Air Canada
Deal found 5/25$354
This Air Canada deal was found by Cheapflights users on 5/21. 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 8/222:35 pm
YOW
-
STL
1 stop5h 07m
Air Canada
Sun 8/308:55 am
STL
-
YOW
1 stop5h 15m
Air Canada
Deal found 5/21$355
This Air Canada deal was found by Cheapflights users on 5/21. 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.
Sun 8/239:00 am
YOW
-
STL
1 stop6h 02m
Air Canada
Sun 8/308:55 am
STL
-
YOW
1 stop5h 15m
Air Canada
Deal found 5/21$360
This Air Canada deal was found by Cheapflights users on 5/22. 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.
Thu 8/1310:00 am
YOW
-
STL
1 stop5h 02m
Air Canada
Sun 8/168:55 am
STL
-
YOW
1 stop7h 15m
Air Canada
Deal found 5/22$375
This Air Canada deal was found by Cheapflights users on 5/21. 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 8/222:35 pm
YOW
-
STL
1 stop5h 07m
Air Canada
Mon 8/318:55 am
STL
-
YOW
1 stop14h 50m
Air Canada
Deal found 5/21$392
This Air Canada deal was found by Cheapflights users on 5/21. 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.
Sun 8/239:00 am
YOW
-
STL
1 stop6h 02m
Air Canada
Tue 9/18:55 am
STL
-
YOW
1 stop14h 50m
Air Canada
Deal found 5/21$397

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 May 26, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$348
(United Airlines)

One-way from

$203
(United Airlines)

Popular in

March

Cheapest in

May

Average price

$359
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. 6% potential increase in price ($35 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($17 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in May 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 May 26, 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

Thu 6/11

6:25 am-3:46 pm

1 stop10h 21m

Lambert-St Louis

Mon 6/15

6:00 am-10:05 pm

1 stop15h 05m

$348

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 7/9

5:50 pm-11:44 pm

1 stop6h 54m

Lambert-St Louis

Sat 7/11

6:00 am-6:48 pm

2 stops11h 48m

$349

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 8/22

5:57 pm-11:38 pm

1 stop6h 41m

Lambert-St Louis

Wed 8/26

8:00 am-9:35 pm

1 stop12h 35m

$349
Quickest round-trip

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 8/25

2:35 pm-6:42 pm

1 stop5h 07m

Lambert-St Louis

Sat 8/29

8:55 am-3:10 pm

1 stop5h 15m

$354

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sun 6/21

6:25 am-3:46 pm

1 stop10h 21m

Lambert-St Louis

Sun 6/28

1:13 pm-9:35 pm

1 stop7h 22m

$431
Cheapest one-way
Quickest one-way

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 7/9

3:10 pm-11:44 pm

1 stop9h 34m

$203

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/24

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

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 May 26, 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
11,090 reviews

Crew

7.8

Entertainment

6.8

Overall

7.1

Comfort

7.1

Boarding

7.3

Food

6.3

Reviews

1 / 20
2.0
Mediocre

Lori,May 2026

YYZ - YFC

Didn't land, sent back to Toronto. No food, no accommodation, no help at all!!
Air Canada
7.1
Good
11,090 reviews
Air Canada
7.1
Good
11,090 reviews

Crew

7.8

Entertainment

6.8

Overall

7.1

Comfort

7.1

Boarding

7.3

Food

6.3

Reviews

1 / 20
2.0
Mediocre

Lori,May 2026

YYZ - YFC

Didn't land, sent back to Toronto. No food, no accommodation, no help at all!!

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 10h 21m. 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 $285 on this airline. You may be able to fly from Ottawa to St. Louis for 41% 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.

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

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

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 May 26, 2026.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$285Average$375FlexibilityNo cancel feeOn-time67%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.
Site
©2026 Cheapflights