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Cheap flights from Ottawa to St. Louis from C$ 249

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 11/12. Fares are subject to change and may not be available on all flights or dates of travel.
YOW — STL
26 Nov — 3 Dec1
1 adult
1 adult, Economy, 0 bags

Cheap 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 27 October 2025.

Round-trip from

C$ 420

One-way from

C$ 249

Popular in

December

Cheapest in

September

Average price

C$ 775
United Airlines
  • United Airlines
  • 19/11-23/11
  • 2 total stops
  • 20h 22m total
  • Ottawa to St. Louis
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Air Canada
  • Air Canada
  • 11/12
  • 1 total stop
  • 6h 09m total
  • Ottawa to St. Louis
Search Deals
Highest demand for flights based on searches. 2% potential increase in price (C$ 36 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease (C$ 22 potential savings vs. average RT price).
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Average for round-trip flights in October 2025
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Find 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 27 October 2025.

Wed 19/1111:10 a.m.YOW - STL
1 stop5h 39mUnited Airlines
Sun 23/116:43 p.m.STL - YOW
1 stop14h 43mUnited Airlines
Deal found 25/10C$ 420
Thu 6/115:55 p.m.YOW - STL
1 stop6h 47mUnited Airlines
Mon 10/1111:05 a.m.STL - YOW
2 stops9h 51mUnited Airlines
Deal found 26/10C$ 656
Sat 20/123:55 p.m.YOW - STL
2 stops18h 45mMultiple Airlines
Mon 5/110:40 a.m.STL - YOW
1 stop29h 33mMultiple Airlines
Deal found 25/10C$ 687
Wed 19/119:25 a.m.YOW - STL
3 stops25h 33mMultiple Airlines
Sun 23/1111:08 a.m.STL - YOW
3 stops29h 17mMultiple Airlines
Deal found 25/10C$ 803
Wed 19/116:45 a.m.YOW - STL
3 stops15h 34mAmerican Airlines
Sun 23/113:35 p.m.STL - YOW
2 stops24h 14mAmerican Airlines
Deal found 25/10C$ 887
Sat 20/1212:05 p.m.YOW - STL
2 stops11h 38mUnited Airlines
Mon 5/16:35 p.m.STL - YOW
2 stops18h 55mUnited Airlines
Deal found 25/10C$ 898

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 27 October 2025.
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

Tue 7/4

6:52 a.m.-12:20 p.m.

1 stop6h 28m

Lambert-St Louis

Wed 8/4

6:30 a.m.-12:41 p.m.

1 stop5h 11m

C$ 420

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 19/11

11:10 a.m.-3:49 p.m.

1 stop5h 39m

Lambert-St Louis

Sun 23/11

6:43 p.m.-10:26 a.m.

1 stop14h 43m

C$ 420

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 7/4

5:45 a.m.-2:18 p.m.

2 stops9h 33m

Lambert-St Louis

Wed 8/4

4:05 p.m.-11:04 p.m.

1 stop5h 59m

C$ 504

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 6/11

5:55 p.m.-11:42 p.m.

1 stop6h 47m

Lambert-St Louis

Mon 10/11

8:25 a.m.-2:27 p.m.

1 stop5h 02m

C$ 656

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 11/12

10:20 a.m.-3:29 p.m.

1 stop6h 09m

C$ 249

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 11/12

5:55 p.m.-12:39 p.m.

2 stops19h 44m

C$ 256

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 11/12

4:35 p.m.-9:47 a.m.

3 stops18h 12m

C$ 302

Flights are sorted by cheapest round-trip flights first.

Deals found on 27/10

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, November is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of C$ 491). Flying from Ottawa to St. Louis in August is currently the most expensive (average of C$ 814). 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 27 October 2025.
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
8,997 reviews
Check prices

Food

6.6

Comfort

7.3

Entertainment

7.1

Overall

7.4

Boarding

7.7

Crew

8.1

Reviews

1 / 20
2.0
Mediocre

Sebrena,Oct 2025

IAH - RSW

The worst that I have ever experienced in my life so bad if it was free I'm not ever going to use your Airline again I dont believe ..... very disappointed 😞 😔0000000000000
United Airlines
7.4
Good
8,997 reviews
United Airlines
7.4
Good
8,997 reviews
Check prices

Food

6.6

Comfort

7.3

Entertainment

7.1

Overall

7.4

Boarding

7.7

Crew

8.1

Reviews

1 / 20
2.0
Mediocre

Sebrena,Oct 2025

IAH - RSW

The worst that I have ever experienced in my life so bad if it was free I'm not ever going to use your Airline again I dont believe ..... very disappointed 😞 😔0000000000000
Air Canada
7.1
Good
10,370 reviews
United Airlines
7.4
Good
8,997 reviews
Check prices

Food

6.6

Comfort

7.3

Entertainment

7.1

Overall

7.4

Boarding

7.7

Crew

8.1

Reviews

1 / 20
2.0
Mediocre

Sebrena,Oct 2025

IAH - RSW

The worst that I have ever experienced in my life so bad if it was free I'm not ever going to use your Airline again I dont believe ..... very disappointed 😞 😔0000000000000

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 28m. Fly via United Airlines to get the fastest option. Airlines will cover a distance of 1413 km.

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

    United Airlines, at C$ 495, 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 43% 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, November is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of C$ 491). Flying from Ottawa to St. Louis in August is currently the most expensive (average of C$ 814). 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
St. Peters

Browse thousands of different options on Cheapflights for your next trip

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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 27 October 2025.
AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapestC$ 495AverageC$ 862FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Air CanadaCheapestC$ 754AverageC$ 883FlexibilityNo 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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