How long is the flight from Ottawa to St. Louis?

Departing from Ottawa to St. Louis will take you 15h 46m. The distance from Ottawa to St. Louis is about 878 mi.

What is the cheapest airline to fly from Ottawa to St. Louis round-trip?

Our cheapest airline available from Ottawa to St. Louis is Air Canada. Our recent data shows that you can find tickets from as low as $350 on this airline. You may be able to fly from Ottawa to St. Louis for 42% less than the average price by searching for this airline.

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.

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).

What is the cheapest time of day to fly from YOW to STL?

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Ottawa to St. Louis as you normally would.

Most accurate provider : When it comes to deals on Ottawa-St. Louis flights, users find the pricing of eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on Ottawa-St. Louis flight deals on Cheapflights vs. eDreams >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 eDreams the most. eDreams 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.

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.

$176+ Flights from Ottawa to St. Louis

Home Search by date Vacation packages Hotels Flight deals Car rental Travel tips & news

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

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 December 4, 2025.

Mon 12/227:27 pmYOW - STL

2 stops18h 00mUnited Airlines

Mon 12/299:55 amSTL - YOW

1 stop10h 23mUnited Airlines

Deal found 12/3

$657

Mon 12/227:15 amYOW - STL

1 stop9h 14mAir Canada

Mon 12/299:55 amSTL - YOW

1 stop10h 23mAir Canada

Deal found 12/3

$671

Best flights from Ottawa to St. Louis
Discover carefully curated flight deals from Ottawa to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated December 4, 2025.

Mon 1/267:27 pmYOW - STL

1 stop15h 46mUnited Airlines

Thu 1/297:00 amSTL - YOW

1 stop5h 32mUnited Airlines

Deal found 12/2

$301

Mon 1/195:40 amYOW - STL

2 stops11h 57mDelta

Sat 1/2410:19 amSTL - YOW

2 stops13h 23mDelta

Deal found 12/3

$469

Thu 1/225:55 pmYOW - STL

1 stop7h 04mUnited Airlines

Sun 1/256:30 amSTL - YOW

2 stops6h 57mUnited Airlines

Deal found 12/4

$301

Mon 12/227:15 amYOW - STL

1 stop9h 14mAir Canada

Mon 12/299:55 amSTL - YOW

1 stop10h 23mAir Canada

Deal found 12/3

$671

Mon 1/265:40 amYOW - STL

2 stops11h 57mDelta

Thu 1/2910:19 amSTL - YOW

2 stops13h 23mDelta

Deal found 12/3

$470

Mon 12/227:27 pmYOW - STL

2 stops18h 00mUnited Airlines

Mon 12/299:55 amSTL - YOW

1 stop10h 23mUnited Airlines

Deal found 12/3

$657

Last-minute flights from Ottawa to St. Louis
Discover last-minute flight deals from Ottawa to St. Louis. Data last updated December 4, 2025 and is based on user searches.

Mon 12/227:27 pmYOW - STL

2 stops18h 00mUnited Airlines

Mon 12/299:55 amSTL - YOW

1 stop10h 23mUnited Airlines

Deal found 12/3

$657

Mon 12/227:15 amYOW - STL

1 stop9h 14mAir Canada

Mon 12/299:55 amSTL - YOW

1 stop10h 23mAir Canada

Deal found 12/3

$671

Mon 1/195:55 pmYOW - STL

1 stop7h 04mUnited Airlines

Sat 1/248:05 amSTL - YOW

1 stop12h 13mUnited Airlines

Deal found 12/4

$301

Mon 1/195:40 amYOW - STL

2 stops11h 57mDelta

Sat 1/2410:19 amSTL - YOW

2 stops13h 23mDelta

Deal found 12/3

$469

Thu 1/224:20 pmYOW - STL

1 stop19h 03mMultiple Airlines

Sun 1/255:42 pmSTL - YOW

1 stop22h 31mMultiple Airlines

Deal found 12/4

$290

Mon 1/267:27 pmYOW - STL

1 stop15h 46mUnited Airlines

Thu 1/297:00 amSTL - YOW

2 stops9h 18mUnited Airlines

Deal found 12/2

$360

One-way flights from Ottawa to St. Louis
Search for one-way flight options from Ottawa to St. Louis. Find affordable one-way fares based on user searches. Data last updated December 4, 2025.

Sun 3/85:55 pmYOW - STL

1 stop6h 56mUnited Airlines

Deal found 12/3

$176

Thu 1/156:20 amYOW - STL

1 stop9h 10mUnited Airlines

Deal found 12/4

$178

Mon 3/24:15 pmYOW - STL

3 stops42h 47mMultiple Airlines

Deal found 12/3

$203

Mon 3/25:40 amYOW - STL

2 stops12h 02mDelta

Deal found 12/3

$210

Thu 1/159:15 amYOW - STL

3 stops22h 36mMultiple Airlines

Deal found 12/4

$238

Mon 3/25:48 pmYOW - STL

1 stop7h 17mUnited Airlines

Deal found 12/3

$243

Sun 3/84:35 pmYOW - STL

3 stops30h 58mMultiple Airlines

Deal found 12/3

$248

Find flight deals from Ottawa to St. Louis

Most accurate provider	eDreams 3 stars
Most trusted provider	eDreams 3 stars
Round-trip from	$295 (Air Canada)
One-way from	$176 (United Airlines)
Popular in	August
Cheapest in	November
Average price	$622

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. 3% potential increase in price ($25 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 1% potential price decrease ($9 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in December 2025

Search Deals

Fly from

Fly to

Route

Depart

Return

Price

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 1/26

7:27 pm-10:13 am

1 stop15h 46m

Lambert-St Louis

Thu 1/29

7:00 am-1:32 pm

1 stop5h 32m

$301

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 1/22

5:55 pm-11:59 pm

1 stop7h 04m

Lambert-St Louis

Sun 1/25

6:30 am-2:27 pm

2 stops6h 57m

$301

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 1/19

5:40 am-4:37 pm

2 stops11h 57m

Lambert-St Louis

Sat 1/24

10:19 am-12:42 am

2 stops13h 23m

$469

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 1/26

5:40 am-4:37 pm

2 stops11h 57m

Lambert-St Louis

Thu 1/29

10:19 am-12:42 am

2 stops13h 23m

$470

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 12/22

7:27 pm-12:27 pm

2 stops18h 00m

Lambert-St Louis

Mon 12/29

9:55 am-9:18 pm

1 stop10h 23m

$657

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 12/22

7:15 am-3:29 pm

1 stop9h 14m

Lambert-St Louis

Mon 12/29

9:55 am-9:18 pm

1 stop10h 23m

$671

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sun 3/8

5:55 pm-11:51 pm

1 stop6h 56m

$176

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 1/15

6:20 am-2:30 pm

1 stop9h 10m

$178

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 3/2

4:15 pm-10:02 am

3 stops42h 47m

$203

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 3/2

5:40 am-4:42 pm

2 stops12h 02m

$210

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/3

Showing 1-10 of 13 results

Compare providers for flights from Ottawa to St. Louis

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ottawa to St. Louis in December.

Provider	Price Accuracy	Trust Score*
FlightHub	Price Accuracy3 stars	Trust Score*1 star
eDreams	Price Accuracy3 stars	Trust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

Most accurate provider: When it comes to deals on Ottawa-St. Louis flights, users find the pricing of eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on Ottawa-St. Louis flight deals on Cheapflights vs. eDreams >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 eDreams the most. eDreams 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, May is the cheapest month in which you can book a flight from Ottawa to St. Louis (average of $273). Flying from Ottawa to St. Louis in August is currently the most expensive (average of $582). 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

Read through reviews of airlines operating flights from Ottawa to St. Louis, such as Air Canada. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

Air Canada

7.1

Good

10,500 reviews

Reviews

1 / 20

10.0

Excellent

Anonymous,Nov 2025

YYZ - LAS

It's was great and the crew are very nice, captain has a smooth land on the runway 👍

Air Canada

7.1

Good

10,500 reviews

Air Canada

7.1

Good

10,500 reviews

Reviews

1 / 20

10.0

Excellent

Anonymous,Nov 2025

YYZ - LAS

It's was great and the crew are very nice, captain has a smooth land on the runway 👍

Related info for your journey

How long is the flight from Ottawa to St. Louis?
Departing from Ottawa to St. Louis will take you 15h 46m. The distance from Ottawa to St. Louis is about 878 mi.
What is the cheapest airline to fly from Ottawa to St. Louis round-trip?
Our cheapest airline available from Ottawa to St. Louis is Air Canada. Our recent data shows that you can find tickets from as low as $350 on this airline. You may be able to fly from Ottawa to St. Louis for 42% less than the average price by searching for this airline.
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 $273). Flying from Ottawa to St. Louis in August is currently the most expensive (average of $582). 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

Edwardsville

O'Fallon

Fairview Heights

Maryland Heights

Collinsville

Swansea

Eureka

Glencoe

St. Peters

Chesterfield

Alton

Farmington

Festus

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for Ottawa to St. Louis

Pearson Intl to St. Louis flights

Pearson Intl to Kansas City flights

Pierre Elliott Trudeau Intl to St. Louis flights

Pierre Elliott Trudeau Intl to Kansas City flights

Ottawa to Kansas City flights

Pearson Intl to Joplin flights

Pearson Intl to Springfield flights

Complete your trip

St. Louis car rentals

Lambert-St Louis Airport car rentals

Springfield Capital Airport car rentals

Belleville Airport car rentals

Marion Williamson County Airport car rentals

Kansas City car rentals

Springfield car rentals

Joplin car rentals

Columbia car rentals

Fort Leonard Wood car rentals

Downtown car rentals

The Hill car rentals

Other flights to St. Louis

Top airline flying from Ottawa to St. Louis

Airline	Cheapest	Average	Flexibility	On-time
Air Canada	Cheapest$350	Average$641	FlexibilityNo cancel fee	On-time67%

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.

$176+ 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 3/8. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Ottawa to St. Louis with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheap flight deals from Ottawa to St. Louis

Cheapest flights from Ottawa to St. LouisExplore 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 December 4, 2025.

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 December 4, 2025.

Find flight deals from Ottawa to St. Louis

Most accurate provider

Most trusted provider

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Cheapflights Fare Finder

Use the filters below to find and compare flights from Ottawa to St. Louis that are best for you.

Compare providers for flights from Ottawa to St. Louis

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ottawa to St. Louis in December.

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.

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?

Reviews of airlines servicing St. Louis

Read through reviews of airlines operating flights from Ottawa to St. Louis, such as Air Canada. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

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?

What is the cheapest airline to fly from Ottawa to St. Louis round-trip?

Can I find deals for flights from Ottawa to St. Louis that include hotel bookings?

How can I find direct flights from Ottawa to St. Louis?

Can I find deals for business class flights from Ottawa to St. Louis?

What is the cheapest month to book a flight from Ottawa to St. Louis?

Traveling to a place near St. Louis?

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.

Alternative routes for Ottawa to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.

Top airline flying from Ottawa to St. Louis

100% Free

Book with Flexibility

Travel Smart

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 December 4, 2025.