Cheap flights from St. Louis to Ottawa from $184

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Ottawa departing on 9/29. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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0 bags

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Find the cheapest flights from St. Louis to Ottawa (STL-YOW)

Cheap round-trip flights

 Logo
1:57 pm - 4:57 pmSTL-YOW
26h 00m1 stop
 Logo
7:00 am - 8:37 pmYOW-STL
14h 37m2 stops
Mon, Sep 29 - Fri, Oct 3
 Logo
10:57 am - 5:25 pmSTL-YOW
29h 28m1 stop
 Logo
6:45 am - 11:01 amYOW-STL
29h 16m2 stops
Tue, Oct 28 - Sat, Jan 24
 Logo
1:57 pm - 4:57 pmSTL-YOW
26h 00m1 stop
 Logo
4:25 pm - 9:40 amYOW-STL
42h 15m2 stops
Mon, Sep 15 - Tue, Sep 23
 Logo
10:57 am - 5:25 pmSTL-YOW
29h 28m1 stop
 Logo
7:00 am - 11:01 amYOW-STL
29h 01m1 stop
Tue, Oct 28 - Sat, Jan 24
United Airlines Logo
7:04 pm - 9:35 pmSTL-YOW
25h 31m1 stop
United Airlines Logo
6:33 am - 2:19 pmYOW-STL
8h 46m1 stop
$587United Airlines
Find Deal
Mon, Sep 15 - Tue, Sep 23
United Airlines Logo
7:04 pm - 2:04 pmSTL-YOW
18h 00m1 stop
United Airlines Logo
5:25 pm - 10:49 amYOW-STL
18h 24m1 stop
$607United Airlines
Find Deal
Wed, Sep 17 - Wed, Sep 24
United Airlines Logo
7:04 pm - 2:04 pmSTL-YOW
18h 00m1 stop
United Airlines Logo
5:15 am - 6:23 pmYOW-STL
14h 08m2 stops
$619United Airlines
Find Deal
Wed, Sep 17 - Wed, Sep 24
 Logo
1:57 pm - 4:57 pmSTL-YOW
26h 00m1 stop
 Logo
7:00 am - 8:40 pmYOW-STL
14h 40m2 stops
Mon, Sep 15 - Fri, Sep 19
United Airlines Logo
6:30 am - 6:52 pmSTL-YOW
11h 22m2 stops
United Airlines Logo
10:25 am - 7:42 pmYOW-STL
10h 17m2 stops
$689United Airlines
Find Deal
Mon, Sep 29 - Fri, Oct 3
WestJet Logo
12:14 pm - 12:45 amSTL-YOW
35h 31m2 stops
WestJet Logo
5:40 am - 9:44 amYOW-STL
29h 04m2 stops
$1,043WestJet
Find Deal
Tue, Oct 28 - Sat, Jan 24

United Airlines flights from St. Louis to Ottawa

Our best United Airlines deals on St. Louis to Ottawa flight tickets
United Airlines
Sep 15
STL7:04 pmLambert-St Louis
25h 31m
1 stop
YOW9:35 pmOttawa
Sep 23
YOW6:33 amOttawa
8h 46m
1 stop
STL2:19 pmLambert-St Louis
United Airlines
Sep 17
STL7:04 pmLambert-St Louis
18h 00m
1 stop
YOW2:04 pmOttawa
Sep 24
YOW5:25 pmOttawa
18h 24m
1 stop
STL10:49 amLambert-St Louis
United Airlines
Sep 17
STL7:04 pmLambert-St Louis
18h 00m
1 stop
YOW2:04 pmOttawa
Sep 24
YOW5:15 amOttawa
14h 08m
2 stops
STL6:23 pmLambert-St Louis

momondo 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, momondo users made 832,500 searches. Data last updated August 21, 2025.
Use the filters below to find and compare flights from St. Louis to Ottawa that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Mon 9/29

1:57 pm-4:57 pm

1 stop26h 00m

Ottawa

Fri 10/3

7:00 am-8:37 pm

2 stops14h 37m

$433

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 10/28

10:57 am-5:25 pm

1 stop29h 28m

Ottawa

Sat 1/24

6:45 am-11:01 am

2 stops29h 16m

$438

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Mon 9/15

1:57 pm-4:57 pm

1 stop26h 00m

Ottawa

Tue 9/23

4:25 pm-9:40 am

2 stops42h 15m

$460

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 10/28

10:57 am-5:25 pm

1 stop29h 28m

Ottawa

Sat 1/24

7:00 am-11:01 am

1 stop29h 01m

$469

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Mon 9/15

7:04 pm-9:35 pm

1 stop25h 31m

Ottawa

Tue 9/23

6:33 am-2:19 pm

1 stop8h 46m

$587

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 9/17

7:04 pm-2:04 pm

1 stop18h 00m

Ottawa

Wed 9/24

5:25 pm-10:49 am

1 stop18h 24m

$607

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 9/17

7:04 pm-2:04 pm

1 stop18h 00m

Ottawa

Wed 9/24

5:15 am-6:23 pm

2 stops14h 08m

$619

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Mon 9/15

1:57 pm-4:57 pm

1 stop26h 00m

Ottawa

Fri 9/19

7:00 am-8:40 pm

2 stops14h 40m

$622

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Mon 9/29

6:30 am-6:52 pm

2 stops11h 22m

Ottawa

Fri 10/3

10:25 am-7:42 pm

2 stops10h 17m

$689

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 10/28

12:14 pm-12:45 am

2 stops35h 31m

Ottawa

Sat 1/24

5:40 am-9:44 am

2 stops29h 04m

$1,043

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 13 resultsSorted by cheapest first
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See travel insights to Ottawa from

How to get the cheapest flight ticket from St. Louis to Ottawa

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest day to depart on your flight to Ottawa?

The cheapest day to depart from St. Louis to Ottawa is on a Saturday. Travelers who choose to depart for Ottawa on a Saturday will often find tickets for as low as $407. Be sure to avoid booking your departure on a Monday as prices are generally higher than usual. According to our data, the average ticket price to Ottawa on Monday is $860.

What is the cheapest time of day to depart on your flight to Ottawa?

In the afternoon is the cheapest time of day to fly from St. Louis to Ottawa when you can find flight prices for as low as $615. Flying to Ottawa in the afternoon is an ideal time because this is during off-peak travel hours. If you have a flexible travel schedule, then try to avoid flying in the morning when prices are $682 on average. Flights to Ottawa from St. Louis in the morning are generally more expensive because this time of day is more convenient for travelers’ schedules.

When to book flights from St. Louis to Ottawa

Are you open to changing your travel dates? Check out the ideal times to fly from St. Louis to Ottawa according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap St. Louis to Ottawa (STL to YOW) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from St. Louis to Ottawa

Direct flights

None
There are no direct flights from St. Louis to Ottawa. There are no popular flight routes from St. Louis to Ottawa.
  • How far is Lambert-St Louis to Ottawa by plane?

    There are 877.2 mi between Lambert-St Louis and Ottawa. By plane, this route typically takes 5h 08m.

  • When did momondo last update prices for flights from Lambert-St Louis Airport to Ottawa Airport?

    Prices for flights from Lambert-St Louis Airport to Ottawa Airport are updated daily.

  • How many operators does momondo search for flights from Lambert-St Louis Airport to Ottawa Airport?

  • How old do you have to be to fly from Lambert-St Louis Airport to Ottawa Airport?

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Lambert-St Louis Airport to Ottawa Airport.

  • What documentation or ID do you need to fly to Ottawa Airport?

    The required travel and health documents for your Ottawa Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Ottawa Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

  • What is the most popular airline from St. Louis to Ottawa?

Best airlines flying from St. Louis to Ottawa

Compare and see reviews for airlines that fly from St. Louis to Ottawa with momondo
Airline
Rating
Free Cancellation
Price
Air CanadaPriceFrom $330Free CancellationRating
7.1
10,000 reviews
Search Air Canada flights
United AirlinesPriceFrom $434Free CancellationRating
7.4
8,930 reviews
Search United Airlines flights

Traveling to a place near Ottawa?

Book flights to Ottawa if you plan to visit one of these locations
Gatineau
Smiths Falls
Calabogie
Brockville
Pembroke
Petawawa
Perth
Prescott
Winchester
Wakefield

Why use momondo?

Why should I use momondo to find a flight deal from St. Louis to Ottawa?

momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from St. Louis to Ottawa. Millions of users trust and use momondo every year so you are in good hands.

Can I find flights from St. Louis to Ottawa with flexible booking policies on momondo?

Yes. momondo enables you to select and highlight flights to Ottawa from St. Louis with this policy.

How can momondo help me find flights from St. Louis to Ottawa?

momondo provides multiple filters to help you find the best flight to Ottawa from St. Louis. Filter by price, airline, airports, cabin, aircraft, payment method, number of stops and more.

I’m not ready to book a flight from St. Louis to Ottawa right now. Can momondo alert me if prices change?

Yes momondo offers price alerts on flights to Ottawa from St. Louis. After performing a search on this page you should be able to see the price alert set up feature. Simply provide a valid email address and momondo will instantly alert you when prices change.

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1 adult
Tue 8/26
Tue 9/2

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