HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Ottawa

$203+ 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 10/11. Fares are subject to change and may not be available on all flights or dates of travel.
STL — YOW
Jul 23 — Jul 301
Wed 7/23
Wed 7/30
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

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 July 18, 2025.

Round-trip from

$425
(Kiwi.com)

One-way from

$203
(Kiwi.com)
From Lambert-St Louis to Ottawa
Search Deals
One-way flight from Lambert-St Louis to Ottawa
Search Deals

Find 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 July 18, 2025.

This Kiwi.com deal was found by Cheapflights users on 7/17. 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.
Thu 8/1410:37 amSTL - YOW
1 stop29h 43mMultiple Airlines
Thu 8/213:50 pmYOW - STL
2 stops22h 42mMultiple Airlines
Deal found 7/17$425
This United Airlines deal was found by Cheapflights users on 7/16. 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 8/309:17 amSTL - YOW
1 stop11h 18mUnited Airlines
Sat 9/66:33 amYOW - STL
1 stop8h 46mUnited Airlines
Deal found 7/16$701
This Booking.com deal was found by Cheapflights users on 7/15. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/303:20 pmSTL - YOW
1 stop5h 15mAir Canada
Sat 9/62:40 pmYOW - STL
1 stop6h 17mAir Canada
Deal found 7/15$746
This Trip.com deal was found by Cheapflights users on 7/17. 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.
Thu 8/143:42 pmSTL - YOW
2 stops7h 40mWestJet
Thu 8/215:55 amYOW - STL
2 stops8h 25mWestJet
Deal found 7/17$763
This Delta deal was found by Cheapflights users on 7/17. 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 7/203:41 pmSTL - YOW
2 stops7h 41mDelta
Sat 7/265:55 amYOW - STL
2 stops11h 36mDelta
Deal found 7/17$1,279

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 July 18, 2025.
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

Thu 8/14

10:37 am-5:20 pm

1 stop29h 43m

Ottawa

Thu 8/21

3:50 pm-1:32 pm

2 stops22h 42m

$425

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sat 8/30

9:17 am-9:35 pm

1 stop11h 18m

Ottawa

Sat 9/6

6:33 am-2:19 pm

1 stop8h 46m

$701

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sat 8/30

3:20 pm-9:35 pm

1 stop5h 15m

Ottawa

Sat 9/6

2:40 pm-7:57 pm

1 stop6h 17m

$746

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Thu 8/14

3:42 pm-12:22 am

2 stops7h 40m

Ottawa

Thu 8/21

5:55 am-1:20 pm

2 stops8h 25m

$763

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 7/20

3:41 pm-12:22 am

2 stops7h 41m

Ottawa

Sat 7/26

5:55 am-4:31 pm

2 stops11h 36m

$1,279

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sat 10/11

7:00 pm-5:20 pm

1 stop21h 20m

$203

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 10/12

6:15 am-6:52 pm

3 stops11h 37m

$1,138

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/17

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, January is the cheapest month in which you can book a flight from St. Louis to Ottawa (average of $294). Flying from St. Louis to Ottawa in September is currently the most expensive (average of $428). 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 July 18, 2025.
Get a feel of what it's like to fly with United Airlines, WestJet, 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
8,864 reviews

Food

6.6

Crew

8.1

Comfort

7.3

Entertainment

7.0

Boarding

7.7

Overall

7.4

Reviews

1 / 20
4.0
Okay

Thomas,Mar 2025

SFO - TPE

When I asked for an extra snack, I got an unhappy look from the stewardess. Geez, does one extra snack really affect the bottom line??
United Airlines
7.4
Good
8,864 reviews
United Airlines
7.4
Good
8,864 reviews

Food

6.6

Crew

8.1

Comfort

7.3

Entertainment

7.0

Boarding

7.7

Overall

7.4

Reviews

1 / 20
4.0
Okay

Thomas,Mar 2025

SFO - TPE

When I asked for an extra snack, I got an unhappy look from the stewardess. Geez, does one extra snack really affect the bottom line??
WestJet
7.2
Good
2,948 reviews
United Airlines
7.4
Good
8,864 reviews

Food

6.6

Crew

8.1

Comfort

7.3

Entertainment

7.0

Boarding

7.7

Overall

7.4

Reviews

1 / 20
4.0
Okay

Thomas,Mar 2025

SFO - TPE

When I asked for an extra snack, I got an unhappy look from the stewardess. Geez, does one extra snack really affect the bottom line??
Air Canada
7.1
Good
9,738 reviews
United Airlines
7.4
Good
8,864 reviews

Food

6.6

Crew

8.1

Comfort

7.3

Entertainment

7.0

Boarding

7.7

Overall

7.4

Reviews

1 / 20
4.0
Okay

Thomas,Mar 2025

SFO - TPE

When I asked for an extra snack, I got an unhappy look from the stewardess. Geez, does one extra snack really affect the bottom line??

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.

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

    Currently priced at $701, United Airlines will fly you from St. Louis to Ottawa and back. In addition to United Airlines, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from Air Canada and WestJet - these airlines can fly you to your destination from $746 and $763, respectively.

  • 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, January is the cheapest month in which you can book a flight from St. Louis to Ottawa (average of $294). Flying from St. Louis to Ottawa in September is currently the most expensive (average of $428). 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 July 18, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$330Average$812FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$434Average$822FlexibilityNo 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.