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$141+ 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 5/14. Fares are subject to change and may not be available on all flights or dates of travel.
STL — YOW
May 1 — May 81
Fri 5/1
Fri 5/8
1 adult, Economy
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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 April 1, 2026.

This Trip.com deal was found by Cheapflights users on 3/29. 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.
Wed 5/131:05 pm
STL
-
YOW
1 stop6h 41m
Air Canada
Wed 5/202:00 pm
YOW
-
STL
1 stop7h 09m
Air Canada
Deal found 3/29$290
This Trip.com 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/167:05 am
STL
-
YOW
1 stop5h 00m
Air Canada
Sat 5/237:00 am
YOW
-
STL
1 stop6h 06m
Air Canada
Deal found 4/1$293
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 5/131:05 pm
STL
-
YOW
1 stop6h 41m
Air Canada
Sun 5/173:00 pm
YOW
-
STL
1 stop6h 25m
Air Canada
Deal found 3/30$334
This Air Canada deal was found by Cheapflights users on 3/31. 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 5/127:05 am
STL
-
YOW
1 stop5h 00m
Air Canada
Mon 5/183:00 pm
YOW
-
STL
1 stop6h 25m
Air Canada
Deal found 3/31$338
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.
Tue 5/127:05 am
STL
-
YOW
1 stop5h 00m
Air Canada
Sat 5/162:35 pm
YOW
-
STL
1 stop6h 50m
Air Canada
Deal found 3/30$339
This United Airlines deal was found by Cheapflights users on 3/31. 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 6/86:00 am
STL
-
YOW
1 stop14h 35m
United Airlines
Wed 6/106:25 am
YOW
-
STL
1 stop10h 21m
United Airlines
Deal found 3/31$342
This Air Canada deal was found by Cheapflights users on 3/31. 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.
Fri 5/157:05 am
STL
-
YOW
1 stop5h 00m
Air Canada
Fri 5/227:00 am
YOW
-
STL
1 stop6h 06m
Air Canada
Deal found 3/31$343
This Flightnetwork 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 Flightnetwork is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/277:45 am
STL
-
YOW
2 stops13h 20m
Air Canada
Mon 5/42:35 pm
YOW
-
STL
1 stop6h 50m
Air Canada
Deal found 3/30$346
This Air Canada deal was found by Cheapflights users on 3/29. 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.
Mon 6/89:23 am
STL
-
YOW
1 stop6h 44m
Air Canada
Wed 6/109:55 am
YOW
-
STL
2 stops6h 51m
Air Canada
Deal found 3/29$422

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 April 1, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$290
(Trip.com)

One-way from

$141
(United Airlines)

Popular in

August

Cheapest in

March

Average price

$590
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. 10% potential increase in price ($76 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($25 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 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 April 1, 2026.
Use the filters below to find and compare flights from St. Louis to Ottawa that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip
Quickest round-trip

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sat 5/16

7:05 am-1:05 pm

1 stop5h 00m

Ottawa

Sat 5/23

7:00 am-12:06 pm

1 stop6h 06m

$293

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 5/12

7:05 am-1:05 pm

1 stop5h 00m

Ottawa

Sat 5/16

2:35 pm-8:25 pm

1 stop6h 50m

$338

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Mon 6/8

7:05 am-1:05 pm

1 stop5h 00m

Ottawa

Wed 6/10

2:35 pm-8:25 pm

1 stop6h 50m

$339

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Mon 6/8

6:00 am-9:35 pm

1 stop14h 35m

Ottawa

Wed 6/10

6:25 am-3:46 pm

1 stop10h 21m

$342

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 5/12

6:30 am-2:22 pm

2 stops6h 52m

Ottawa

Sat 5/16

6:25 am-9:13 pm

1 stop15h 48m

$352
Cheapest one-way

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Thu 5/14

7:45 am-5:07 pm

1 stop8h 22m

$141
Quickest one-way

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 7/8

7:22 am-1:59 pm

1 stop5h 37m

$154

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Thu 5/14

6:55 pm-5:35 pm

2 stops45h 40m

$179

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Fri 4/10

7:45 am-5:07 pm

1 stop8h 22m

$221

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 7/8

8:08 pm-5:40 pm

3 stops20h 32m

$296

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/30

Showing 1-10 of 12 resultsSorted by cheapest first
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.

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

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 April 1, 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
9,529 reviews

Food

6.6

Boarding

7.7

Comfort

7.3

Crew

8.1

Overall

7.4

Entertainment

7.1

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
9,529 reviews
United Airlines
7.4
Good
9,529 reviews

Food

6.6

Boarding

7.7

Comfort

7.3

Crew

8.1

Overall

7.4

Entertainment

7.1

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
10,873 reviews
United Airlines
7.4
Good
9,529 reviews

Food

6.6

Boarding

7.7

Comfort

7.3

Crew

8.1

Overall

7.4

Entertainment

7.1

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 5h. Air Canada provides one of the quickest options available for as low as $293. 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 $359. Air Canada is 79% 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

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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 April 1, 2026.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$139Average$697FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$359Average$754FlexibilityNo cancel feeOn-time69%

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