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Cheap flights from Portland, Maine to St. Louis from $159

1 adult
1 adult, Economy, 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
4:27 pm - 9:46 pmPWM  Portland-STL Lambert-St Louis
6h 19m1 stop New York LaGuardia
American Airlines Logo
9:16 am - 4:47 pmSTL  Lambert-St Louis-PWM Portland
6h 31m1 stop New York LaGuardia
$339American Airlines
Wed, Oct 7 - Sat, Oct 17
American Airlines Logo
6:00 am - 12:35 pmPWM  Portland-STL Lambert-St Louis
7h 35m1 stop Washington, D.C. Reagan-National
American Airlines Logo
5:08 pm - 11:59 pmSTL  Lambert-St Louis-PWM Portland
5h 51m1 stop Washington, D.C. Reagan-National
$339American Airlines
Wed, Oct 7 - Tue, Oct 13
American Airlines Logo
4:27 pm - 9:46 pmPWM  Portland-STL Lambert-St Louis
6h 19m1 stop New York LaGuardia
American Airlines Logo
5:27 pm - 11:40 pmSTL  Lambert-St Louis-PWM Portland
5h 13m1 stop Chicago O'Hare Intl
$339American Airlines
Wed, Oct 7 - Tue, Oct 13
Southwest Logo
3:25 pm - 9:55 pmPWM  Portland-STL Lambert-St Louis
7h 30m2 stops Baltimore/Washington Nashville Intl
Southwest Logo
6:25 am - 12:25 pmSTL  Lambert-St Louis-PWM Portland
5h 00m1 stop Baltimore/Washington
$344Southwest
Wed, Nov 4 - Sat, Nov 7
United Airlines Logo
8:45 am - 3:43 pmPWM  Portland-STL Lambert-St Louis
7h 58m2 stops Newark Chicago O'Hare Intl
United Airlines Logo
8:30 am - 2:16 pmSTL  Lambert-St Louis-PWM Portland
4h 46m1 stop Chicago O'Hare Intl
$344United Airlines
Wed, Nov 4 - Sat, Nov 7
United Airlines Logo
5:08 pm - 9:21 pmPWM  Portland-STL Lambert-St Louis
5h 13m1 stop Chicago O'Hare Intl
United Airlines Logo
2:56 pm - 11:59 pmSTL  Lambert-St Louis-PWM Portland
8h 03m2 stops Chicago O'Hare Intl Washington, D.C. Dulles Intl
$344United Airlines
Wed, Oct 7 - Sat, Oct 17
Southwest Logo
3:25 pm - 9:55 pmPWM  Portland-STL Lambert-St Louis
7h 30m2 stops Baltimore/Washington Nashville Intl
Southwest Logo
5:45 am - 2:45 pmSTL  Lambert-St Louis-PWM Portland
8h 00m2 stops Chicago Midway Baltimore/Washington
$349Southwest
Wed, Nov 4 - Sat, Nov 7
United Airlines Logo
6:00 am - 10:48 amPWM  Portland-STL Lambert-St Louis
5h 48m1 stop Chicago O'Hare Intl
United Airlines Logo
8:30 am - 2:16 pmSTL  Lambert-St Louis-PWM Portland
4h 46m1 stop Chicago O'Hare Intl
$362United Airlines
Fri, Oct 16 - Mon, Oct 26
Southwest Logo
3:25 pm - 10:10 pmPWM  Portland-STL Lambert-St Louis
7h 45m1 stop Baltimore/Washington
Southwest Logo
6:20 am - 2:45 pmSTL  Lambert-St Louis-PWM Portland
7h 25m2 stops Chicago Midway Baltimore/Washington
$367Southwest
Mon, Nov 16 - Thu, Nov 19
Delta Logo
4:45 pm - 8:35 pmPWM  Portland-STL Lambert-St Louis
4h 50m1 stop Detroit Metropolitan Wayne County
Delta Logo
1:40 pm - 9:00 pmSTL  Lambert-St Louis-PWM Portland
6h 20m1 stop Atlanta Hartsfield-Jackson
$428Delta
Tue, Sep 8 - Sat, Sep 12

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United Airlines flights from Portland, Maine to St. Louis

Our best United Airlines deals on Portland, Maine to St. Louis flight tickets
United Airlines
Oct 16
PWM6:00 amPortland
5h 48m
1 stop
STL10:48 amLambert-St Louis
Oct 26
STL8:30 amLambert-St Louis
4h 46m
1 stop
PWM2:16 pmPortland
$362
United Airlines
Nov 4
PWM8:45 amPortland
7h 58m
2 stops
STL3:43 pmLambert-St Louis
Nov 6
STL7:30 amLambert-St Louis
5h 46m
1 stop
PWM2:16 pmPortland
$367
United Airlines
Oct 9
PWM6:00 amPortland
6h 22m
1 stop
STL11:22 amLambert-St Louis
Oct 13
STL3:11 pmLambert-St Louis
5h 43m
1 stop
PWM9:54 pmPortland
$373

Southwest flights from Portland, Maine to St. Louis

Our best Southwest deals on Portland, Maine to St. Louis flight tickets
Southwest
Nov 4
PWM3:25 pmPortland
7h 30m
2 stops
STL9:55 pmLambert-St Louis
Nov 7
STL6:25 amLambert-St Louis
5h 00m
1 stop
PWM12:25 pmPortland
$344
Southwest
Nov 4
PWM3:25 pmPortland
7h 30m
2 stops
STL9:55 pmLambert-St Louis
Nov 7
STL5:45 amLambert-St Louis
8h 00m
2 stops
PWM2:45 pmPortland
$349
Southwest
Nov 4
PWM3:25 pmPortland
7h 30m
2 stops
STL9:55 pmLambert-St Louis
Nov 6
STL7:45 amLambert-St Louis
7h 45m
2 stops
PWM4:30 pmPortland
$385

momondo Fare Finder

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

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Route

Depart

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Price

Cheapest round-trip

PortlandSt. Louis

PWM Portland - STL Lambert-St Louis

PWMSTL

Portland

Wed 10/7

4:27 pm-9:46 pm

1 stop6h 19m

Lambert-St Louis

Sat 10/17

9:16 am-4:47 pm

1 stop6h 31m

$339

PortlandSt. Louis

PWM Portland - STL Lambert-St Louis

PWMSTL

Portland

Wed 10/7

6:00 am-12:35 pm

1 stop7h 35m

Lambert-St Louis

Tue 10/13

5:08 pm-11:59 pm

1 stop5h 51m

$339

PortlandSt. Louis

PWM Portland - STL Lambert-St Louis

PWMSTL

Portland

Wed 10/7

4:27 pm-9:46 pm

1 stop6h 19m

Lambert-St Louis

Tue 10/13

5:27 pm-11:40 pm

1 stop5h 13m

$339

PortlandSt. Louis

PWM Portland - STL Lambert-St Louis

PWMSTL

Portland

Wed 11/4

3:25 pm-9:55 pm

2 stops7h 30m

Lambert-St Louis

Sat 11/7

6:25 am-12:25 pm

1 stop5h 00m

$344

PortlandSt. Louis

PWM Portland - STL Lambert-St Louis

PWMSTL

Portland

Wed 11/4

8:45 am-3:43 pm

2 stops7h 58m

Lambert-St Louis

Sat 11/7

8:30 am-2:16 pm

1 stop4h 46m

$344

PortlandSt. Louis

PWM Portland - STL Lambert-St Louis

PWMSTL

Portland

Wed 10/7

5:08 pm-9:21 pm

1 stop5h 13m

Lambert-St Louis

Sat 10/17

2:56 pm-11:59 pm

2 stops8h 03m

$344

PortlandSt. Louis

PWM Portland - STL Lambert-St Louis

PWMSTL

Portland

Wed 11/4

3:25 pm-9:55 pm

2 stops7h 30m

Lambert-St Louis

Sat 11/7

5:45 am-2:45 pm

2 stops8h 00m

$349
Quickest round-trip

PortlandSt. Louis

PWM Portland - STL Lambert-St Louis

PWMSTL

Portland

Fri 10/16

6:00 am-10:48 am

1 stop5h 48m

Lambert-St Louis

Mon 10/26

8:30 am-2:16 pm

1 stop4h 46m

$362

PortlandSt. Louis

PWM Portland - STL Lambert-St Louis

PWMSTL

Portland

Mon 11/16

3:25 pm-10:10 pm

1 stop7h 45m

Lambert-St Louis

Thu 11/19

6:20 am-2:45 pm

2 stops7h 25m

$367

PortlandSt. Louis

PWM Portland - STL Lambert-St Louis

PWMSTL

Portland

Tue 9/8

4:45 pm-8:35 pm

1 stop4h 50m

Lambert-St Louis

Sat 9/12

1:40 pm-9:00 pm

1 stop6h 20m

$428

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?

Prices are currently typical for flights on this route.

Typical prices usually range from $333 to $526.
The lowest price recently found on this route was $339.

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

In general, March 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 $354. The month of May is another great option to travel to St. Louis, with average flight prices from Portland, Maine averaging around $407.

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

As of August 2026, prices for Portland, Maine to St. Louis flights are approximately 51% more expensive 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

Best Price Found

$159

Fastest flight time

5h 12m

Direct flights

None
The best one-way flight to St. Louis from Portland, Maine in the past 72 hours is $159. The best round-trip flight deal from Portland, Maine to St. Louis found on momondo in the last 72 hours is $339.
The fastest flight from Portland, Maine to St. Louis takes 5h 12m
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 12m 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 $268Free CancellationRating
7.8
8,531 reviews
Search Delta flights
American AirlinesPriceFrom $316Free CancellationRating
7.1
12,012 reviews
Search American Airlines flights
SouthwestPriceFrom $348Free CancellationRating
8.0
4,203 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
Fairview Heights
Maryland Heights
St. Peters
Hermann
Alton
Florissant
Collinsville
O'Fallon
Farmington
Clayton
Fenton
Festus
Wentzville
Eureka
Edwardsville
Litchfield
Grafton
Shrewsbury

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.

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