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Cheap flights from Portland, Maine to St. Louis from $168

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Portland, Maine to St. Louis departing on 5/23. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from Portland, Maine to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
American Airlines Logo
7:10 am - 1:22 pm
PWM
-
STL
7h 12m
1 stop
American Airlines Logo
6:00 am - 12:40 pm
STL
-
PWM
5h 40m
1 stop
$259American Airlines
Wed, May 20 - Wed, May 27
American Airlines Logo
10:47 am - 3:13 pm
PWM
-
STL
5h 26m
1 stop
American Airlines Logo
5:00 pm - 12:35 am
STL
-
PWM
6h 35m
1 stop
$275American Airlines
Wed, May 20 - Wed, May 27
American Airlines Logo
7:19 pm - 11:54 pm
PWM
-
STL
5h 35m
1 stop
American Airlines Logo
5:00 pm - 12:35 am
STL
-
PWM
6h 35m
1 stop
$311American Airlines
Fri, May 29 - Tue, Jun 2
Delta Logo
11:03 am - 3:40 pm
PWM
-
STL
5h 37m
1 stop
Delta Logo
4:25 pm - 12:43 am
STL
-
PWM
7h 18m
1 stop
$324Delta
Tue, May 26 - Thu, Jun 4
Southwest Logo
7:10 pm - 11:00 pm
PWM
-
STL
4h 50m
1 stop
Southwest Logo
5:20 pm - 12:05 am
STL
-
PWM
5h 45m
1 stop
$343Southwest
Wed, Jun 10 - Mon, Jun 15
Southwest Logo
3:55 pm - 9:05 pm
PWM
-
STL
6h 10m
1 stop
Southwest Logo
4:25 pm - 12:05 am
STL
-
PWM
6h 40m
2 stops
$349Southwest
Tue, May 26 - Thu, Jun 4
Delta Logo
6:00 am - 12:20 pm
PWM
-
STL
7h 20m
1 stop
Delta Logo
6:45 am - 11:55 am
STL
-
PWM
4h 10m
1 stop
$353Delta
Sun, May 17 - Tue, May 19
United Airlines Logo
5:30 am - 12:47 pm
PWM
-
STL
8h 17m
2 stops
United Airlines Logo
6:00 am - 1:25 pm
STL
-
PWM
6h 25m
1 stop
$354United Airlines
Wed, May 20 - Wed, May 27
Southwest Logo
1:05 pm - 6:25 pm
PWM
-
STL
6h 20m
2 stops
Southwest Logo
5:20 pm - 12:05 am
STL
-
PWM
5h 45m
1 stop
$357Southwest
Wed, Jun 10 - Mon, Jun 15
Delta Logo
6:00 am - 12:20 pm
PWM
-
STL
7h 20m
1 stop
Delta Logo
10:51 am - 5:52 pm
STL
-
PWM
6h 01m
1 stop
$369Delta
Thu, Jun 4 - Sun, Jun 7

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American Airlines flights from Portland, Maine to St. Louis

Our best American Airlines deals on Portland, Maine to St. Louis flight tickets
American Airlines
May 20
PWM7:10 amPortland
7h 12m
1 stop
STL1:22 pmLambert-St Louis
May 27
STL6:00 amLambert-St Louis
5h 40m
1 stop
PWM12:40 pmPortland
$259
American Airlines
May 20
PWM10:47 amPortland
5h 26m
1 stop
STL3:13 pmLambert-St Louis
May 27
STL5:00 pmLambert-St Louis
6h 35m
1 stop
PWM12:35 amPortland
$275
American Airlines
May 29
PWM7:19 pmPortland
5h 35m
1 stop
STL11:54 pmLambert-St Louis
Jun 2
STL5:00 pmLambert-St Louis
6h 35m
1 stop
PWM12:35 amPortland
$311

United Airlines flights from Portland, Maine to St. Louis

Our best United Airlines deals on Portland, Maine to St. Louis flight tickets
United Airlines
May 20
PWM5:30 amPortland
8h 17m
2 stops
STL12:47 pmLambert-St Louis
May 27
STL6:00 amLambert-St Louis
6h 25m
1 stop
PWM1:25 pmPortland
$354
United Airlines
May 23
PWM6:00 amPortland
5h 34m
1 stop
STL10:34 amLambert-St Louis
May 27
STL6:00 amLambert-St Louis
6h 25m
1 stop
PWM1:25 pmPortland
$375
United Airlines
May 23
PWM10:04 amPortland
10h 19m
2 stops
STL7:23 pmLambert-St Louis
May 27
STL6:00 amLambert-St Louis
6h 25m
1 stop
PWM1:25 pmPortland
$390

momondo Fare Finder

 
Customize your flight search to find flights from Portland, Maine 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, momondo users made 832,500 searches. Data last updated April 24, 2026.
Use the filters below to find and compare flights from Portland, Maine to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 5/20

7:10 am-1:22 pm

1 stop7h 12m

Lambert-St Louis

Wed 5/27

6:00 am-12:40 pm

1 stop5h 40m

$259

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 5/20

10:47 am-3:13 pm

1 stop5h 26m

Lambert-St Louis

Wed 5/27

5:00 pm-12:35 am

1 stop6h 35m

$275

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Fri 5/29

7:19 pm-11:54 pm

1 stop5h 35m

Lambert-St Louis

Tue 6/2

5:00 pm-12:35 am

1 stop6h 35m

$311

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Tue 5/26

11:03 am-3:40 pm

1 stop5h 37m

Lambert-St Louis

Thu 6/4

4:25 pm-12:43 am

1 stop7h 18m

$324
Quickest round-trip

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 6/10

7:10 pm-11:00 pm

1 stop4h 50m

Lambert-St Louis

Mon 6/15

5:20 pm-12:05 am

1 stop5h 45m

$343

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Tue 5/26

3:55 pm-9:05 pm

1 stop6h 10m

Lambert-St Louis

Thu 6/4

4:25 pm-12:05 am

2 stops6h 40m

$349

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sun 5/17

6:00 am-12:20 pm

1 stop7h 20m

Lambert-St Louis

Tue 5/19

6:45 am-11:55 am

1 stop4h 10m

$353

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 5/20

5:30 am-12:47 pm

2 stops8h 17m

Lambert-St Louis

Wed 5/27

6:00 am-1:25 pm

1 stop6h 25m

$354

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 6/10

1:05 pm-6:25 pm

2 stops6h 20m

Lambert-St Louis

Mon 6/15

5:20 pm-12:05 am

1 stop5h 45m

$357

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Thu 6/4

6:00 am-12:20 pm

1 stop7h 20m

Lambert-St Louis

Sun 6/7

10:51 am-5:52 pm

1 stop6h 01m

$369

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to St. Louis from

How to get the cheapest flight ticket from Portland, Maine to St. Louis

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 typical price of a round-trip flight between Portland, Maine and St. Louis?

What is the cheapest month to fly to St. Louis?

In general, September is the cheapest month to fly from Portland, Maine to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $333. The month of March is another great option to travel to St. Louis, with average flight prices from Portland, Maine averaging around $344.

How have Portland, Maine to St. Louis flight prices changed over time?

As of April 2026, prices for Portland, Maine to St. Louis flights are approximately 17% cheaper when compared to flights at the same time last year.

When to book flights from Portland, Maine to St. Louis

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

Cheap Portland, Maine to St. Louis (PWM to STL) flight deals and tips

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

Fastest flight time

5h 01m

Direct flights

None
The fastest flight from Portland, Maine to St. Louis takes 5h 01m
There are no direct flights from Portland, Maine to St. Louis. There are no popular flight routes from Portland, Maine to St. Louis.
Search flight deals

Frequently asked questions about flying from Portland, Maine to St. Louis

  • How far is Portland to Lambert-St Louis by plane?

    The distance between Portland and Lambert-St Louis is about 1090.4 mi. 5h 01m is a normal flight duration for this route.

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

    Prices for flights from Portland Airport to Lambert-St Louis Airport refresh daily.

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

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

    Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Portland Airport to Lambert-St Louis Airport.

  • What documentation or ID do you need to fly to Lambert-St Louis Airport?

    The travel and health documents you'll need for your trip to Lambert-St Louis Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Lambert-St Louis Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

  • What is the most popular airline from Portland, Maine to St. Louis?

Best airlines flying from Portland, Maine to St. Louis

Compare and see reviews for airlines that fly from Portland, Maine to St. Louis with momondo
Airline
Rating
Free Cancellation
Price
DeltaPriceFrom $236Free CancellationRating
7.9
8,451 reviews
Search Delta flights
American AirlinesPriceFrom $296Free CancellationRating
7.1
11,666 reviews
Search American Airlines flights
SouthwestPriceFrom $348Free CancellationRating
8.0
4,334 reviews
Search Southwest flights

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
St. Charles
Chesterfield
Hermann
Fairview Heights
Maryland Heights
O'Fallon
Florissant
St. Peters
Collinsville
Wentzville
Alton
Fenton
Farmington
Festus
Clayton
Eureka
Litchfield
Edwardsville
Shrewsbury
Grafton

Why use momondo?

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

Finding the right flight to St. Louis from Portland is quick and easy when you have a range of options in front of you, from reputable agents and recognisable airlines. Options that can then be filtered down to find the best fit. That is what momondo does. We make finding flights to St. Louis quick and easy, saving you time and money.

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

Flights from Portland to St. Louis with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.

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

momondo helps you find the best flight between Portland and St. Louis by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.

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

If you are simply researching potential flights to St. Louis, momondo offers a useful price alert feature which will track prices for flights to St. Louis from Portland and alert you when they change.

An easier way to manage your St. Louis trip

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