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Cheap flights from St. Louis to Boston from $130

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 Boston departing on 1/18. 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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Cheap round-trip flights

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Multiple Airlines Logo
8:32 pm - 10:22 am
STL
-
PWM
36h 50m2 stops
Multiple Airlines Logo
9:47 am - 11:33 pm
PWM
-
STL
14h 46m1 stop
$299Multiple Airlines
Mon, Jan 19 - Mon, Jan 26
United Airlines Logo
7:00 am - 1:56 pm
STL
-
PWM
5h 56m1 stop
United Airlines Logo
7:27 pm - 11:59 pm
PWM
-
STL
5h 32m1 stop
$335United Airlines
Mon, Jan 19 - Mon, Jan 26
Delta Logo
6:35 am - 12:08 pm
STL
-
PWM
4h 33m1 stop
Delta Logo
12:43 pm - 8:06 pm
PWM
-
STL
8h 23m1 stop
$344Delta
Sun, Jan 18 - Sun, Jan 25
United Airlines Logo
8:05 am - 2:39 pm
STL
-
PWM
5h 34m1 stop
United Airlines Logo
6:00 am - 2:30 pm
PWM
-
STL
9h 30m2 stops
$349United Airlines
Sun, Jan 18 - Sun, Jan 25
Multiple Airlines Logo
10:57 am - 9:06 am
STL
-
PWM
21h 09m2 stops
Multiple Airlines Logo
11:02 am - 10:33 pm
PWM
-
STL
12h 31m1 stop
$364Multiple Airlines
Sun, Jan 4 - Wed, Jan 7
United Airlines Logo
8:30 am - 2:29 pm
STL
-
PWM
4h 59m1 stop
United Airlines Logo
4:10 pm - 10:58 pm
PWM
-
STL
7h 48m1 stop
$388United Airlines
Sat, Jan 17 - Tue, Jan 20
United Airlines Logo
8:05 am - 6:54 pm
STL
-
PWM
9h 49m2 stops
United Airlines Logo
4:10 pm - 10:58 pm
PWM
-
STL
7h 48m1 stop
$393United Airlines
Sat, Jan 17 - Tue, Jan 20
American Airlines Logo
12:03 pm - 9:24 pm
STL
-
PWM
8h 21m1 stop
American Airlines Logo
5:30 pm - 11:24 pm
PWM
-
STL
6h 54m1 stop
$402American Airlines
Tue, Apr 14 - Sat, Apr 18
Delta Logo
9:00 am - 6:01 pm
STL
-
PWM
8h 01m1 stop
Delta Logo
6:50 pm - 11:38 pm
PWM
-
STL
5h 48m1 stop
$407Delta
Sun, Jun 7 - Sun, Jun 14
Delta Logo
6:45 am - 5:00 pm
STL
-
PWM
9h 15m2 stops
Delta Logo
6:50 pm - 11:38 pm
PWM
-
STL
5h 48m1 stop
$412Delta
Sat, Jun 20 - Fri, Jun 26

American Airlines flights from St. Louis to Portland, Maine

Our best American Airlines deals on St. Louis to Portland, Maine flight tickets
American Airlines
Apr 14
STL12:03 pmLambert-St Louis
8h 21m
1 stop
PWM9:24 pmPortland
Apr 18
PWM5:30 pmPortland
6h 54m
1 stop
STL11:24 pmLambert-St Louis
$402
Find similar
American Airlines
Mar 27
STL9:32 amLambert-St Louis
6h 22m
1 stop
PWM4:54 pmPortland
Mar 30
PWM5:38 pmPortland
7h 14m
1 stop
STL11:52 pmLambert-St Louis
$431
Find similar
American Airlines
Jun 19
STL2:23 pmLambert-St Louis
4h 50m
1 stop
PWM8:13 pmPortland
Jun 26
PWM2:38 pmPortland
7h 22m
1 stop
STL9:00 pmLambert-St Louis
$499
Find similar

Southwest flights from St. Louis to Portland, Maine

Our best Southwest deals on St. Louis to Portland, Maine flight tickets
Southwest
Mar 27
STL5:20 amLambert-St Louis
5h 35m
1 stop
PWM11:55 amPortland
Mar 30
PWM12:35 pmPortland
6h 15m
1 stop
STL5:50 pmLambert-St Louis
$427
Find similar
Southwest
Mar 27
STL4:25 pmLambert-St Louis
6h 40m
2 stops
PWM12:05 amPortland
Mar 30
PWM12:35 pmPortland
6h 15m
1 stop
STL5:50 pmLambert-St Louis
$432
Find similar
Southwest
Mar 27
STL4:25 pmLambert-St Louis
6h 40m
2 stops
PWM12:05 amPortland
Mar 30
PWM2:50 pmPortland
7h 05m
2 stops
STL8:55 pmLambert-St Louis
$437
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from St. Louis to Portland, Maine 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 December 23, 2025.
Use the filters below to find and compare flights from St. Louis to Portland, Maine that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Mon 1/19

8:32 pm-10:22 am

2 stops36h 50m

Portland

Mon 1/26

9:47 am-11:33 pm

1 stop14h 46m

$299

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Mon 1/19

7:00 am-1:56 pm

1 stop5h 56m

Portland

Mon 1/26

7:27 pm-11:59 pm

1 stop5h 32m

$335

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sun 1/18

6:35 am-12:08 pm

1 stop4h 33m

Portland

Sun 1/25

12:43 pm-8:06 pm

1 stop8h 23m

$344

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sun 1/18

8:05 am-2:39 pm

1 stop5h 34m

Portland

Sun 1/25

6:00 am-2:30 pm

2 stops9h 30m

$349

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sun 1/4

10:57 am-9:06 am

2 stops21h 09m

Portland

Wed 1/7

11:02 am-10:33 pm

1 stop12h 31m

$364

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sat 1/17

8:30 am-2:29 pm

1 stop4h 59m

Portland

Tue 1/20

4:10 pm-10:58 pm

1 stop7h 48m

$388

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sat 1/17

8:05 am-6:54 pm

2 stops9h 49m

Portland

Tue 1/20

4:10 pm-10:58 pm

1 stop7h 48m

$393

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Tue 4/14

12:03 pm-9:24 pm

1 stop8h 21m

Portland

Sat 4/18

5:30 pm-11:24 pm

1 stop6h 54m

$402

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sun 6/7

9:00 am-6:01 pm

1 stop8h 01m

Portland

Sun 6/14

6:50 pm-11:38 pm

1 stop5h 48m

$407

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sat 6/20

6:45 am-5:00 pm

2 stops9h 15m

Portland

Fri 6/26

6:50 pm-11:38 pm

1 stop5h 48m

$412

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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How to get the cheapest flight ticket from St. Louis to Portland, Maine

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 month to fly to Portland, Maine?

The cheapest month to fly to Portland, Maine from St. Louis is in February. Flight prices, which tend to average around $386, are often lower during this time because this is during the off-season. If you aren’t able to travel to Portland, Maine during the month of February, then flying in December is also cheap. Prices for this month can be found on momondo for an average of $386.

What is the cheapest day to depart on your flight to Portland, Maine?

On average, the least expensive day to fly to Portland, Maine from St. Louis is on a Tuesday. momondo users have found tickets for Tuesday departures for as low as $375. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Friday is the most expensive day to depart from St. Louis because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $456.

What is the cheapest time of day to depart on your flight to Portland, Maine?

In the evening is the cheapest time of day to fly from St. Louis to Portland, Maine when you can find flight prices for as low as $285. Flying to Portland, Maine in the evening is an ideal time because this is during off-peak travel hours. Try not to purchase tickets at noon because they tend to be around $436. Of course, these prices can vary depending on the time of year and what airport you fly to.

How far in advance should I book a flight to Portland, Maine?

You are more likely to see cheaper flights to Portland, Maine from St. Louis when booking weeks ahead of your departure date. In general, you can expect to find flights to Portland, Maine for around $437 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Portland, Maine from St. Louis for as low as $339 on momondo.

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

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

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

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

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

Fastest flight time

4h 10m

Direct flights

None
The fastest flight from St. Louis to Portland, Maine takes 4h 10m
There are no direct flights from St. Louis to Portland, Maine. There are no popular flight routes from St. Louis to Portland, Maine.
Search flight deals

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

    Portland is 1090.4 mi away from Lambert-St Louis. In terms of flight time, this usually takes a little over 4h 10m.

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

    Prices for flights from Lambert-St Louis Airport to Portland Airport are refreshed on a daily basis.

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

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

    The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Lambert-St Louis Airport to Portland Airport.

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

    The travel and health documents you'll need for your trip to Portland 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 Portland 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 St. Louis to Portland, Maine?

Best airlines flying from St. Louis to Portland, Maine

Compare and see reviews for airlines that fly from St. Louis to Portland, Maine with momondo
Airline
Rating
Free Cancellation
Price
United AirlinesPriceFrom $212Free CancellationRating
7.4
9,105 reviews
Search United Airlines flights
SouthwestPriceFrom $284Free CancellationRating
8.0
4,253 reviews
Search Southwest flights
American AirlinesPriceFrom $284Free CancellationRating
7.2
11,054 reviews
Search American Airlines flights
DeltaPriceFrom $286Free CancellationRating
7.9
8,014 reviews
Search Delta flights

Traveling to a place near Boston?

Book flights to Boston if you plan to visit one of these locations
North Conway
Boothbay Harbor
Jackson
Conway
Freeport
Lewiston
Brunswick
Bartlett
Gorham
Auburn
Windham
Intervale
Oxford
Bath
Georgetown
Falmouth
Tamworth

Why use momondo?

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

momondo collates all your flight options in one place and lets you filter them to find the perfect flight from St. Louis to Portland. momondo saves you time and could save you money on your trip.

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

All flight searches from St. Louis to Portland on momondo can be filtered to show those which offer flexible booking policies.

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

momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from St. Louis to Portland.

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

Price alerts on flights to Portland from St. Louis are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.

An easier way to manage your Portland, Maine trip

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