HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Ottawa

$150+ Cheap flights from St. Louis (STL) to Ottawa (YOW)

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 4/11. Fares are subject to change and may not be available on all flights or dates of travel.
STL — YOW
Mar 16 — Mar 231
Mon 3/16
Mon 3/23
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from St. Louis to Ottawa 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 St. Louis to Ottawa

Cheapest flights from St. Louis to Ottawa
Explore the most affordable flight options available from St. Louis to Ottawa. Find the lowest fares from popular airlines and budget airlines, with prices last updated on February 14, 2026.

This Air Canada deal was found by Cheapflights users on 2/13. 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 5/107:30 am
STL
-
YOW
1 stop4h 40m
Air Canada
Wed 5/132:25 pm
YOW
-
STL
1 stop6h 40m
Air Canada
Deal found 2/13$353
This United Airlines deal was found by Cheapflights users on 2/11. 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 3/286:25 am
STL
-
YOW
1 stop9h 47m
United Airlines
Sat 4/410:44 am
YOW
-
STL
1 stop12h 03m
United Airlines
Deal found 2/11$355
This United Airlines deal was found by Cheapflights users on 2/13. 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.
Sun 3/17:41 am
STL
-
YOW
1 stop8h 26m
United Airlines
Sat 3/75:11 pm
YOW
-
STL
1 stop5h 30m
United Airlines
Deal found 2/13$356
This Kiwi.com deal was found by Cheapflights users on 2/12. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 3/294:51 pm
STL
-
YOW
1 stop30h 11m
Multiple Airlines
Sun 4/53:05 pm
YOW
-
STL
2 stops21h 22m
Multiple Airlines
Deal found 2/12$436
This United Airlines deal was found by Cheapflights users on 2/10. 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.
Mon 2/237:00 am
STL
-
YOW
1 stop5h 34m
United Airlines
Wed 2/256:20 am
YOW
-
STL
1 stop15h 45m
United Airlines
Deal found 2/10$441
This United Airlines deal was found by Cheapflights users on 2/13. 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.
Sun 5/107:30 am
STL
-
YOW
1 stop4h 40m
United Airlines
Wed 5/1310:00 am
YOW
-
STL
2 stops12h 08m
United Airlines
Deal found 2/13$445
This Delta deal was found by Cheapflights users on 2/13. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/106:40 am
STL
-
YOW
2 stops9h 55m
Delta
Wed 5/135:55 am
YOW
-
STL
2 stops12h 51m
Delta
Deal found 2/13$483
This American Airlines deal was found by Cheapflights users on 2/13. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 3/13:33 pm
STL
-
YOW
2 stops24h 15m
American Airlines
Sat 3/76:45 am
YOW
-
STL
2 stops25h 53m
American Airlines
Deal found 2/13$495

Find flight deals from St. Louis to Ottawa

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Ottawa (YOW). 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 February 14, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$353
(Air Canada)

One-way from

$150
(United Airlines)

Popular in

July

Cheapest in

March

Average price

$362
Provider with most accurate pricing for Lambert-St Louis-Ottawa flight deals.
Search Deals
Provider most trusted by Cheapflights users for Lambert-St Louis-Ottawa flights.
Search Deals
From Lambert-St Louis to Ottawa
Search Deals
One-way flight from Lambert-St Louis to Ottawa
Search Deals
Highest demand for flights based on searches. 20% potential increase in price ($183 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 6% potential price decrease ($42 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in February 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from St. Louis to Ottawa 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 February 14, 2026.
Use the filters below to find and compare flights from St. Louis to Ottawa that are best for you.

Fly from

St. Louis

Fly to

Ottawa

Route

Depart

Return

Price

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 5/10

7:30 am-1:10 pm

1 stop4h 40m

Ottawa

Wed 5/13

2:25 pm-8:05 pm

1 stop6h 40m

$353

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sat 3/28

6:25 am-5:12 pm

1 stop9h 47m

Ottawa

Sat 4/4

10:44 am-9:47 pm

1 stop12h 03m

$355

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 3/1

7:41 am-5:07 pm

1 stop8h 26m

Ottawa

Sat 3/7

5:11 pm-9:41 pm

1 stop5h 30m

$356

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 3/29

7:45 am-1:59 pm

1 stop5h 14m

Ottawa

Sun 4/5

5:20 pm-9:08 pm

1 stop4h 48m

$356

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 3/29

4:51 pm-12:02 am

1 stop30h 11m

Ottawa

Sun 4/5

3:05 pm-11:27 am

2 stops21h 22m

$436

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 5/10

7:30 am-1:10 pm

1 stop4h 40m

Ottawa

Wed 5/13

10:00 am-9:08 pm

2 stops12h 08m

$445

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 3/29

12:04 pm-12:39 am

2 stops11h 35m

Ottawa

Sun 4/5

5:40 am-4:32 pm

2 stops11h 52m

$495

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 3/1

3:33 pm-4:48 pm

2 stops24h 15m

Ottawa

Sat 3/7

6:45 am-7:38 am

2 stops25h 53m

$495

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 3/29

7:05 am-6:23 pm

2 stops10h 18m

Ottawa

Sun 4/5

6:45 am-6:07 pm

3 stops12h 22m

$722

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 5/10

6:07 pm-2:55 pm

3 stops19h 48m

Ottawa

Wed 5/13

7:00 am-10:19 pm

2 stops16h 19m

$832

Flights are sorted by cheapest round-trip flights first.

Deals found on 2/11

Showing 1-10 of 17 results
1
2
  • Most accurate provider: When it comes to deals on St. Louis-Ottawa flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Ottawa flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from St. Louis-Ottawa flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on St. Louis-Ottawa 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 St. Louis-Ottawa 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 St. Louis to Ottawa

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

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

Currently, March is the cheapest month in which you can book a flight from St. Louis to Ottawa (average of $179). Flying from St. Louis to Ottawa in January is currently the most expensive (average of $642). 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.

Reviews of airlines servicing Ottawa

Get insights into the airlines that provide service to Ottawa. 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 Ottawa. Reviews last updated February 14, 2026.
Get a feel of what it's like to fly with United Airlines and Air Canada from St. Louis to Ottawa by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
United Airlines
7.4
Good
9,289 reviews

Crew

8.1

Comfort

7.3

Entertainment

7.1

Food

6.6

Overall

7.4

Boarding

7.7

Reviews

1 / 20
10.0
Excellent

Dane,Jan 2026

TYS - IAD

It was a short flight, so no time for amenities. Just glad everything was quick and easy from boarding to arriving at my destination with my family
United Airlines
7.4
Good
9,289 reviews
United Airlines
7.4
Good
9,289 reviews

Crew

8.1

Comfort

7.3

Entertainment

7.1

Food

6.6

Overall

7.4

Boarding

7.7

Reviews

1 / 20
10.0
Excellent

Dane,Jan 2026

TYS - IAD

It was a short flight, so no time for amenities. Just glad everything was quick and easy from boarding to arriving at my destination with my family
Air Canada
7.1
Good
10,717 reviews
United Airlines
7.4
Good
9,289 reviews

Crew

8.1

Comfort

7.3

Entertainment

7.1

Food

6.6

Overall

7.4

Boarding

7.7

Reviews

1 / 20
10.0
Excellent

Dane,Jan 2026

TYS - IAD

It was a short flight, so no time for amenities. Just glad everything was quick and easy from boarding to arriving at my destination with my family

Related info for your journey

Find useful and relevant information for your journey from St. Louis to Ottawa. 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 St. Louis to Ottawa?

    A quick flight from St. Louis to Ottawa can take about 4h 40m. Air Canada provides one of the quickest options available for as low as $353. St. Louis and Ottawa are separated by a distance of 878 mi. This flight may include one or multiple stops.

  • What are the cheapest airlines flying from St. Louis to Ottawa round-trip?

    Currently priced at $139, Air Canada will fly you from St. Louis to Ottawa and back. In addition to Air Canada, many other airlines offer competitively priced options for your trip. Check Cheapflights for deals on United Airlines for as low as $362. Air Canada is 80% cheaper than the average price of flights available within the next 90 days to this destination.

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

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

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

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

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

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

    Currently, March is the cheapest month in which you can book a flight from St. Louis to Ottawa (average of $179). Flying from St. Louis to Ottawa in January is currently the most expensive (average of $642). 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 Ottawa?

Book flights to Ottawa if you plan to visit one of these locations
Gatineau
Petawawa

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.

Top 2 airlines flying from St. Louis to Ottawa

Discover the top 2 airlines that operate flights from St. Louis to Ottawa. 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 February 14, 2026.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$139Average$812FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$362Average$824FlexibilityNo cancel feeOn-time69%

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.