HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
St. Louis

$215+ Cheap flights from Ottawa (YOW) to St. Louis (STL)

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 6/18. Fares are subject to change and may not be available on all flights or dates of travel.
YOW — STL
May 19 — May 261
Mon 5/19
Mon 5/26
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Ottawa to St. Louis 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 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 May 14, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
2 stars

Round-trip from

$346
(Kiwi.com)

One-way from

$215
(Mytrip)

Popular in

August

Cheapest in

September

Average price

$677
Provider with most accurate pricing for Ottawa-Lambert-St Louis flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ottawa-Lambert-St Louis flights.
Search Deals
From Ottawa to Lambert-St Louis
Search Deals
One-way flight from Ottawa to Lambert-St Louis
Search Deals
Highest demand for flights based on searches. 2% potential increase in price ($16 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($10 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in May 2025
Search Deals

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 May 14, 2025.

This Kiwi.com deal was found by Cheapflights users on 5/13. 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.
Fri 5/304:25 pmYOW - STL
1 stop8h 27mMultiple Airlines
Wed 6/185:47 pmSTL - YOW
1 stop22h 19mMultiple Airlines
Deal found 5/13$346
This FlightHub deal was found by Cheapflights users on 5/13. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/305:55 amYOW - STL
2 stops8h 24mWestJet
Fri 6/66:00 amSTL - YOW
2 stops17h 21mWestJet
Deal found 5/13$561
This United Airlines deal was found by Cheapflights users on 5/13. 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.
Wed 6/116:40 amYOW - STL
1 stop17h 05mUnited Airlines
Wed 6/189:50 amSTL - YOW
1 stop10h 45mUnited Airlines
Deal found 5/13$589
This Air Canada deal was found by Cheapflights users on 5/13. 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 7/42:25 pmYOW - STL
1 stop6h 35mAir Canada
Fri 7/111:30 pmSTL - YOW
1 stop5h 45mAir Canada
Deal found 5/13$618

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 2,558,603 searches. Data last updated May 14, 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

Fri 5/30

4:25 pm-11:52 pm

1 stop8h 27m

Lambert-St Louis

Wed 6/18

5:47 pm-5:06 pm

1 stop22h 19m

$346

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Fri 5/30

5:55 am-1:19 pm

2 stops8h 24m

Lambert-St Louis

Fri 6/6

6:00 am-12:21 am

2 stops17h 21m

$561

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 6/11

6:40 am-10:45 pm

1 stop17h 05m

Lambert-St Louis

Wed 6/18

9:50 am-9:35 pm

1 stop10h 45m

$589

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Fri 7/4

2:25 pm-8:00 pm

1 stop6h 35m

Lambert-St Louis

Fri 7/11

1:30 pm-8:15 pm

1 stop5h 45m

$618

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 6/18

7:00 am-5:04 pm

3 stops35h 04m

$215

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 6/28

6:33 am-10:40 am

1 stop5h 07m

$331

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/14

  • Most accurate provider: When it comes to deals on Ottawa-St. Louis flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ottawa-St. Louis flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ottawa-St. Louis flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ottawa-St. Louis 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 Ottawa-St. Louis 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 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, August is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of $311). Flying from Ottawa to St. Louis in March is currently the most expensive (average of $356). 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.

Rainfall in St. Louis by month

Plan your trip to St. Louis by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in St. Louis ranges from 2.2 - 4.7 inches per month. May is typically the wettest month, when rainfall can reach 4.7 in. February is typically the driest time to visit St. Louis when rainfall is around 2.2 in.

Temperature in St. Louis by month

Plan your trip to St. Louis by taking into account the average temperature totals by month.

If weather is an important factor for your trip to St. Louis, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 80.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 32.0 F).

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 May 14, 2025.
Peruse reviews from past customers who have flown with United Airlines, WestJet and Air Canada from Ottawa to St. Louis to help guide your decision. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
United Airlines
7.4
Good
8,730 reviews

Boarding

7.7

Comfort

7.3

Entertainment

7.1

Crew

8.1

Overall

7.4

Food

6.6

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
8,730 reviews
United Airlines
7.4
Good
8,730 reviews

Boarding

7.7

Comfort

7.3

Entertainment

7.1

Crew

8.1

Overall

7.4

Food

6.6

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
2,841 reviews
United Airlines
7.4
Good
8,730 reviews

Boarding

7.7

Comfort

7.3

Entertainment

7.1

Crew

8.1

Overall

7.4

Food

6.6

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
7.0
Good
9,333 reviews
United Airlines
7.4
Good
8,730 reviews

Boarding

7.7

Comfort

7.3

Entertainment

7.1

Crew

8.1

Overall

7.4

Food

6.6

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?

    Our cheapest airline available from Ottawa to St. Louis is WestJet. Our recent data shows that you can find tickets from as low as $561 on this airline. Additional options worth looking into are United Airlines and Air Canada, starting at $589 and $618 round-trip. You may be able to fly from Ottawa to St. Louis for 13% less than the average price by searching for these airlines.

  • 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, August is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of $311). Flying from Ottawa to St. Louis in March is currently the most expensive (average of $356). 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
Fenton
Maryland Heights
Fairview Heights
Collinsville
Wentzville
Eureka
St. Peters
Festus
Glencoe
Alton
Farmington
O'Fallon

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.

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.