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Cheap flights from Ottawa to St. Louis from C$ 326

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 10/9. Fares are subject to change and may not be available on all flights or dates of travel.
YOW — STL
3 Aug — 10 Aug1
1 adult

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 29 July 2025.

Round-trip from

C$ 716

One-way from

C$ 326

Popular in

August

Cheapest in

September

Average price

C$ 934
21/8-25/8
  • 21/8-25/8
  • 5 total stops
  • 47h 57m total
  • Ottawa to St. Louis
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10/9
  • 10/9
  • 3 total stops
  • 21h 30m total
  • Ottawa to St. Louis
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High demand for flights, 0% potential price rise
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Cheapest flight prices on average. 1% potential price decrease (C$ 17 potential savings vs. average RT price).
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Average for round-trip flights in July 2025
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Find 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 29 July 2025.

Thu 21/84:25 p.m.YOW - STL
2 stops22h 07mMultiple Airlines
Mon 25/82:30 p.m.STL - YOW
3 stops25h 50mMultiple Airlines
Deal found 29/7C$ 716
Thu 11/95:25 p.m.YOW - STL
1 stop23h 19mUnited Airlines
Thu 18/97:04 p.m.STL - YOW
1 stop25h 31mUnited Airlines
Deal found 28/7C$ 794
Thu 21/85:55 a.m.YOW - STL
2 stops8h 25mWestJet
Mon 25/83:42 p.m.STL - YOW
2 stops7h 40mWestJet
Deal found 29/7C$ 899
Thu 21/82:25 p.m.YOW - STL
1 stop6h 35mAir Canada
Mon 25/81:30 p.m.STL - YOW
1 stop5h 45mAir Canada
Deal found 29/7C$ 927

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 29 July 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

Thu 21/8

4:25 p.m.-1:32 p.m.

2 stops22h 07m

Lambert-St Louis

Mon 25/8

2:30 p.m.-5:20 p.m.

3 stops25h 50m

C$ 716

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 11/9

5:25 p.m.-3:44 p.m.

1 stop23h 19m

Lambert-St Louis

Thu 18/9

7:04 p.m.-9:35 p.m.

1 stop25h 31m

C$ 794

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 21/8

5:55 a.m.-1:20 p.m.

2 stops8h 25m

Lambert-St Louis

Mon 25/8

3:42 p.m.-12:22 a.m.

2 stops7h 40m

C$ 899

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 21/8

2:25 p.m.-8:00 p.m.

1 stop6h 35m

Lambert-St Louis

Mon 25/8

1:30 p.m.-8:15 p.m.

1 stop5h 45m

C$ 927

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 10/9

2:20 p.m.-10:50 a.m.

3 stops21h 30m

C$ 326

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 10/9

6:33 a.m.-3:44 p.m.

1 stop10h 11m

C$ 395

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 15/9

2:40 p.m.-7:57 p.m.

1 stop6h 17m

C$ 432

Flights are sorted by cheapest round-trip flights first.

Deals found on 26/7

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, January is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of C$ 365). Flying from Ottawa to St. Louis in September is currently the most expensive (average of C$ 491). 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.

What’s the top layover airport for flights from Ottawa to St. Louis?

Share of one-stop round-trip flights from Ottawa to St. Louis chosen by Cheapflights users in the past 12 months, using the same layover each way.

Chicago (ORD) – chosen by Cheapflights users on 63% of one-stop itineraries from Ottawa to St. Louis on Cheapflights.

What’s the cheapest layover airport for flights from Ottawa to St. Louis?

Average round-trip fare for 1-stop flights from Ottawa to St. Louis, chosen by Cheapflights users in the past 12 months, with the same layover each way.

Toronto (YYZ) is the most affordable 1-stop option, with an average round-trip price of C$ 789.

What’s the fastest layover option from Ottawa to St. Louis?

Shortest average travel time for 1-stop one-way flights from Ottawa to St. Louis, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by layover airport.

Flights via Chicago (ORD) have the shortest average one-way travel time for 1-stop routes: 2h 41m.

Which airport typically offers the quickest layover for flights from Ottawa to St. Louis?

Average layover duration for 1-stop one-way flights from Ottawa to St. Louis, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via Chicago (ORD) offer the fastest connection on this route, with an average layover time of 1h 17m.

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 29 July 2025.
Check out reviews from past customers who have flown with United Airlines,WestJet, andAir 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
8,899 reviews
Check prices

Boarding

7.7

Entertainment

7.1

Comfort

7.3

Crew

8.1

Food

6.6

Overall

7.4

Reviews

1 / 20
4.0
Okay

Thomas,Apr 2025

TPE - SFO

The boarding experience was okay. The dietary food choices were limited, the midway snacks were hard and dry. The seat was uncomfortable - stiff seat cushion, seat back kept springing back to the upright position, narrow seat width. Love the app and the ability to track my luggage. Flight crew was efficient.
United Airlines
7.4
Good
8,899 reviews
United Airlines
7.4
Good
8,899 reviews
Check prices

Boarding

7.7

Entertainment

7.1

Comfort

7.3

Crew

8.1

Food

6.6

Overall

7.4

Reviews

1 / 20
4.0
Okay

Thomas,Apr 2025

TPE - SFO

The boarding experience was okay. The dietary food choices were limited, the midway snacks were hard and dry. The seat was uncomfortable - stiff seat cushion, seat back kept springing back to the upright position, narrow seat width. Love the app and the ability to track my luggage. Flight crew was efficient.
WestJet
7.2
Good
2,973 reviews
United Airlines
7.4
Good
8,899 reviews
Check prices

Boarding

7.7

Entertainment

7.1

Comfort

7.3

Crew

8.1

Food

6.6

Overall

7.4

Reviews

1 / 20
4.0
Okay

Thomas,Apr 2025

TPE - SFO

The boarding experience was okay. The dietary food choices were limited, the midway snacks were hard and dry. The seat was uncomfortable - stiff seat cushion, seat back kept springing back to the upright position, narrow seat width. Love the app and the ability to track my luggage. Flight crew was efficient.
Air Canada
7.1
Good
9,822 reviews
United Airlines
7.4
Good
8,899 reviews
Check prices

Boarding

7.7

Entertainment

7.1

Comfort

7.3

Crew

8.1

Food

6.6

Overall

7.4

Reviews

1 / 20
4.0
Okay

Thomas,Apr 2025

TPE - SFO

The boarding experience was okay. The dietary food choices were limited, the midway snacks were hard and dry. The seat was uncomfortable - stiff seat cushion, seat back kept springing back to the upright position, narrow seat width. Love the app and the ability to track my luggage. Flight crew was efficient.

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.

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

    United Airlines, at C$ 794, was found to be the cheapest airline from Ottawa to St. Louis.Alternate airlines to your destination round-trip include WestJet and Air Canada. United Airlines is currently priced 10% 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, January is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of C$ 365). Flying from Ottawa to St. Louis in September is currently the most expensive (average of C$ 491). 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

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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 629,999 searches. Data last updated 29 July 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapestC$ 761AverageC$ 885FlexibilityNo 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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