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Cheap flights from Ottawa to St. Louis from C$ 244

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 9/4. Fares are subject to change and may not be available on all flights or dates of travel.
YOW — STL
25 Feb — 4 Mar1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Ottawa to St. Louis

Enter your travel dates to find the best prices.

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 26 January 2026.

Sat 16/57:00 a.m.
YOW
-
STL
1 stop6h 06m
Air Canada
Mon 18/57:30 a.m.
STL
-
YOW
1 stop4h 40m
Air Canada
Deal found 26/1C$ 470
Sat 16/510:25 a.m.
YOW
-
STL
2 stops12h 27m
United Airlines
Mon 18/57:30 a.m.
STL
-
YOW
1 stop4h 40m
United Airlines
Deal found 26/1C$ 557
Mon 2/27:27 p.m.
YOW
-
STL
1 stop15h 46m
United Airlines
Thu 5/27:00 a.m.
STL
-
YOW
1 stop5h 32m
United Airlines
Deal found 25/1C$ 594
Mon 2/22:15 p.m.
YOW
-
STL
2 stops9h 43m
Air Canada
Thu 5/28:05 a.m.
STL
-
YOW
2 stops9h 33m
Air Canada
Deal found 25/1C$ 679
Sat 16/58:40 a.m.
YOW
-
STL
2 stops11h 46m
American Airlines
Mon 18/56:00 a.m.
STL
-
YOW
2 stops7h 55m
American Airlines
Deal found 26/1C$ 733

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 26 January 2026.

Round-trip from

C$ 470

One-way from

C$ 244

Popular in

August

Cheapest in

January

Average price

C$ 556
Air Canada
  • Air Canada
  • 16/5-18/5
  • 2 total stops
  • 10h 46m total
  • Ottawa to St. Louis
Search Deals
Air Canada
  • Air Canada
  • 9/4
  • 1 total stop
  • 7h 09m total
  • Ottawa to St. Louis
Search Deals
Highest demand for flights based on searches. 6% potential increase in price (C$ 77 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease (C$ 21 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in January 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 629,999 searches. Data last updated 26 January 2026.
Use the filters below to find and compare flights from Ottawa to St. Louis that are best for you.

Fly from

Ottawa

Fly to

St. Louis

Route

Depart

Return

Price

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 16/5

7:00 a.m.-12:06 p.m.

1 stop6h 06m

Lambert-St Louis

Mon 18/5

7:30 a.m.-1:10 p.m.

1 stop4h 40m

C$ 470

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 16/5

10:25 a.m.-9:52 p.m.

2 stops12h 27m

Lambert-St Louis

Mon 18/5

7:30 a.m.-1:10 p.m.

1 stop4h 40m

C$ 557

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 16/5

8:40 a.m.-7:26 p.m.

2 stops11h 46m

Lambert-St Louis

Mon 18/5

6:00 a.m.-2:55 p.m.

2 stops7h 55m

C$ 733

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 9/4

9:15 a.m.-3:24 p.m.

1 stop7h 09m

C$ 244

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 12/3

5:55 p.m.-11:51 p.m.

1 stop6h 56m

C$ 256

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 9/4

6:00 a.m.-4:56 p.m.

2 stops11h 56m

C$ 300

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 9/4

4:35 p.m.-11:55 p.m.

3 stops32h 20m

C$ 341

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 12/3

3:35 p.m.-1:34 p.m.

3 stops22h 59m

C$ 345

Flights are sorted by cheapest round-trip flights first.

Deals found on 25/1

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 C$ 374). Flying from Ottawa to St. Louis in August is currently the most expensive (average of C$ 797). 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 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 26 January 2026.
Check out reviews from past customers who have flown with United Airlines and Air Canada from Ottawa to St. Louis to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
United Airlines
7.4
Good
9,200 reviews
Check prices

Comfort

7.3

Food

6.6

Boarding

7.7

Crew

8.1

Overall

7.4

Entertainment

7.1

Reviews

1 / 20
6.0
Good

Gerry,Jan 2026

YVR - DEN

Seats were uncomfortable. Second leg of my flight on United had much more comfortable seats
United Airlines
7.4
Good
9,200 reviews
United Airlines
7.4
Good
9,200 reviews
Check prices

Comfort

7.3

Food

6.6

Boarding

7.7

Crew

8.1

Overall

7.4

Entertainment

7.1

Reviews

1 / 20
6.0
Good

Gerry,Jan 2026

YVR - DEN

Seats were uncomfortable. Second leg of my flight on United had much more comfortable seats
Air Canada
7.1
Good
10,656 reviews
United Airlines
7.4
Good
9,200 reviews
Check prices

Comfort

7.3

Food

6.6

Boarding

7.7

Crew

8.1

Overall

7.4

Entertainment

7.1

Reviews

1 / 20
6.0
Good

Gerry,Jan 2026

YVR - DEN

Seats were uncomfortable. Second leg of my flight on United had much more comfortable seats

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?

    There are many flights that can get you from Ottawa to St. Louis in 6h 06m. Fly via Air Canada, United Airlines, or American Airlines to get the fastest option. Airlines will cover a distance of 1413 km. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

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

    United Airlines, at C$ 476, was found to be the cheapest airline from Ottawa to St. Louis. An alternate airline flying to your destination would be Air Canada. United Airlines is currently priced 41% below the average price you’ll pay for this route.

  • 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 C$ 374). Flying from Ottawa to St. Louis in August is currently the most expensive (average of C$ 797). 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

Travelling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
Chesterfield

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Top 2 airlines flying from Ottawa to St. Louis

Discover the top 2 airlines 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 629,999 searches. Data last updated 26 January 2026.
AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapestC$ 476AverageC$ 754FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Air CanadaCheapestC$ 485AverageC$ 864FlexibilityNo cancel feeOn-time67%
Search Air Canada flights

Fly with Cheapflights

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How does Cheapflights help users find flights from Ottawa to St. Louis?

When you search for this flight from Ottawa to St. Louis, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

Why should you use Cheapflights to find cheap flight tickets from Ottawa to St. Louis?

Cheapflights helps you find that perfect flight to St. Louis from Ottawa by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

Can Cheapflights find flights from Ottawa to St. Louis with no change fees?

Users can book flights with no change fees policies with our dedicated filters. Book flights from Ottawa to St. Louis flexibly with Cheapflights today.

Can Cheapflights notify me if prices for flights from Ottawa to St. Louis become cheaper?

Yes! Start tracking prices for Ottawa to St. Louis flights today and get alerted whenever prices for these flights change. To access this feature, click the bell icon next to the flight deals above, which will prompt you for a valid email address to receive your alerts.

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