What is the cheapest airline that flies from Lambert-St Louis to Portland?

United Airlines, Southwest, and Delta are the most popular carriers operating from Lambert-St Louis to Portland

Which layover airport has the shortest connection time from St. Louis to Portland, Maine?

Detroit (DTW) has the shortest average layover time for this route: 0h 56m.

How many flights depart from St. Louis to Portland, Maine on average per week?

The number of flights available between St. Louis and Portland, Maine is 3 per week as of November 2025. The most frequent departure day is Thu, with 33% of weekly flights leaving on this day.

What airlines fly to Portland, Maine?

American Airlines, Southwest and Delta are the top three most popular airlines that fly to Portland, Maine from St. Louis according to our data. American Airlines is the first choice among our users, with 60% of people opting to fly with this airline when traveling to Portland, Maine. Keep in mind that there are 6 different airlines that fly to Portland, Maine on a routine basis, so you have a few additional options to choose from.

Which airport is the most popular layover for flights between St. Louis and Portland, Maine?

Detroit (DTW) was the most common stop: 75% of momondo users choosing 1-stop flights on this route connected there.

Which layover airport has the shortest travel time from St. Louis to Portland, Maine?

Flights connecting via Detroit (DTW) have the shortest average one-way travel time: 4h 33m.

Which layover airport offers the lowest fares from St. Louis to Portland, Maine?

Flights via Atlanta (ATL) offer the lowest average round-trip price of $387.

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?

The number of operators available for flights from Lambert-St Louis Airport to Portland Airport is 4 as of November 2025.

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.

$146 Cheap Flights from St. Louis to Portland in 2025/26

1 adult

0 bags

Discover deals from 900+ travel sites with momondo.

Save money when you book flights with momondo

Big names and deals

Search 100s of travel sites to compare prices.

Filter for what you want

Free Wi-Fi? Stopover? Instantly customize your results.

Trusted and free

We’re completely free to use - no hidden charges or fees.

Price Alerts

Not ready to book? to track prices.

Search flight deals

Find the cheapest flights from St. Louis to Portland

Round-trip

One-way

Last minute

Cheap round-trip flights

Enter your travel dates to find the best prices.

3:30 pm - 10:36 amSTL-PWM

18h 06m1 stop

9:46 am - 10:33 pmPWM-STL

13h 47m1 stop

$287Multiple Airlines

Find Deal

Tue, Dec 9 - Fri, Dec 12

6:35 am - 12:00 pmSTL-PWM

4h 25m1 stop

6:00 am - 12:25 pmPWM-STL

7h 25m1 stop

$318Delta

Find Deal

Sat, Feb 28 - Wed, Mar 4

6:25 am - 2:40 pmSTL-PWM

7h 15m2 stops

3:30 pm - 10:00 pmPWM-STL

7h 30m1 stop

$323Southwest

Find Deal

Sat, Dec 6 - Tue, Dec 9

12:20 pm - 9:55 pmSTL-PWM

8h 35m2 stops

5:30 am - 12:35 pmPWM-STL

8h 05m2 stops

$328Southwest

Find Deal

Sat, Dec 6 - Tue, Dec 9

5:45 am - 12:05 pmSTL-PWM

5h 20m1 stop

3:15 pm - 7:30 pmPWM-STL

5h 15m1 stop

$337Southwest

Find Deal

Sat, Dec 6 - Sat, Dec 6

5:45 am - 12:05 pmSTL-PWM

5h 20m1 stop

3:30 pm - 10:00 pmPWM-STL

7h 30m1 stop

$342Southwest

Find Deal

Sat, Dec 6 - Mon, Dec 8

5:00 am - 11:20 amSTL-PWM

5h 20m1 stop

5:20 pm - 9:45 pmPWM-STL

5h 25m1 stop

$353American Airlines

Find Deal

Thu, Dec 25 - Fri, Jan 2

6:00 am - 12:05 pmSTL-PWM

5h 05m1 stop

7:00 am - 1:16 pmPWM-STL

7h 16m1 stop

$398American Airlines

Find Deal

Sat, Feb 28 - Wed, Mar 4

3:10 pm - 11:59 pmSTL-PWM

7h 49m2 stops

6:00 am - 4:27 pmPWM-STL

11h 27m2 stops

$399United Airlines

Find Deal

Thu, Dec 25 - Fri, Jan 2

8:05 am - 2:14 pmSTL-PWM

5h 09m1 stop

7:08 pm - 11:33 pmPWM-STL

5h 25m1 stop

$422United Airlines

Find Deal

Sun, Dec 21 - Sat, Dec 27

Delta flights from St. Louis to Portland, Maine

Our best Delta deals on St. Louis to Portland, Maine flight tickets

Delta

Feb 28

STL6:35 amLambert-St Louis

4h 25m

1 stop

PWM12:00 pmPortland

Mar 4

PWM6:00 amPortland

7h 25m

1 stop

STL12:25 pmLambert-St Louis

$318

Find similar

Delta

Feb 28

STL1:00 pmLambert-St Louis

9h 49m

2 stops

PWM11:49 pmPortland

Mar 4

PWM2:35 pmPortland

10h 05m

2 stops

STL11:40 pmLambert-St Louis

$359

Find similar

Delta

Dec 6

STL6:39 amLambert-St Louis

4h 34m

1 stop

PWM12:13 pmPortland

Dec 6

PWM4:45 pmPortland

7h 42m

2 stops

STL11:27 pmLambert-St Louis

$373

Find similar

Southwest flights from St. Louis to Portland, Maine

Our best Southwest deals on St. Louis to Portland, Maine flight tickets

Southwest

Dec 6

STL6:25 amLambert-St Louis

7h 15m

2 stops

PWM2:40 pmPortland

Dec 9

PWM3:30 pmPortland

7h 30m

1 stop

STL10:00 pmLambert-St Louis

$323

Find similar

Southwest

Dec 6

STL12:20 pmLambert-St Louis

8h 35m

2 stops

PWM9:55 pmPortland

Dec 9

PWM5:30 amPortland

8h 05m

2 stops

STL12:35 pmLambert-St Louis

$328

Find similar

Southwest

Dec 6

STL5:45 amLambert-St Louis

5h 20m

1 stop

PWM12:05 pmPortland

Dec 6

PWM3:15 pmPortland

5h 15m

1 stop

STL7:30 pmLambert-St Louis

$337

Find similar

momondo Fare Finder

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

Tue 12/9

3:30 pm-10:36 am

1 stop18h 06m

Portland

Fri 12/12

9:46 am-10:33 pm

1 stop13h 47m

$287

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sat 2/28

6:35 am-12:00 pm

1 stop4h 25m

Portland

Wed 3/4

6:00 am-12:25 pm

1 stop7h 25m

$318

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sat 12/6

6:25 am-2:40 pm

2 stops7h 15m

Portland

Tue 12/9

3:30 pm-10:00 pm

1 stop7h 30m

$323

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sat 12/6

12:20 pm-9:55 pm

2 stops8h 35m

Portland

Tue 12/9

5:30 am-12:35 pm

2 stops8h 05m

$328

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sat 12/6

5:45 am-12:05 pm

1 stop5h 20m

Portland

Sat 12/6

3:15 pm-7:30 pm

1 stop5h 15m

$337

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sat 12/6

5:45 am-12:05 pm

1 stop5h 20m

Portland

Mon 12/8

3:30 pm-10:00 pm

1 stop7h 30m

$342

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Thu 12/25

5:00 am-11:20 am

1 stop5h 20m

Portland

Fri 1/2

5:20 pm-9:45 pm

1 stop5h 25m

$353

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sat 2/28

6:00 am-12:05 pm

1 stop5h 05m

Portland

Wed 3/4

7:00 am-1:16 pm

1 stop7h 16m

$398

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Thu 12/25

3:10 pm-11:59 pm

2 stops7h 49m

Portland

Fri 1/2

6:00 am-4:27 pm

2 stops11h 27m

$399

St. LouisPortland

STL - PWM

STLPWM

Lambert-St Louis

Sun 12/21

8:05 am-2:14 pm

1 stop5h 09m

Portland

Sat 12/27

7:08 pm-11:33 pm

1 stop5h 25m

$422

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first

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

Prices

Airlines

Layovers

Other information

What is the cheapest month to fly to Portland, Maine?

The cheapest month to fly to Portland, Maine from St. Louis is in January. Flight prices, which tend to average around $374, 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 January, then flying in November is also cheap. Prices for this month can be found on momondo for an average of $381.

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 $421 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 $325 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

Direct flights	None

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 12m.
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?
The number of operators available for flights from Lambert-St Louis Airport to Portland Airport is 4 as of November 2025.
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?
Based on momondo bookings for flights between St. Louis and Portland, Maine, the leading airline is American Airlines, making up 54% of the total bookings. Other popular airlines include Delta with 30%, Southwest with 12%, and United Airlines with 4%.

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 Airlines	PriceFrom $212	Free Cancellation	Rating 7.4 8,997 reviews	Search United Airlines flights
American Airlines	PriceFrom $284	Free Cancellation	Rating 7.2 11,038 reviews	Search American Airlines flights
Delta	PriceFrom $298	Free Cancellation	Rating 7.9 8,002 reviews	Search Delta flights
Southwest	PriceFrom $308	Free Cancellation	Rating 8.0 4,238 reviews	Search Southwest flights

Southwest Flights From St. Louis to Portland, Maine
Southwest operates around 3 flights from St. Louis to Portland, Maine every week. The average price of these flights found in the last 72 hours has been $498, but momondo users have found Southwest deals from St. Louis to Portland, Maine from as low as $308 round-trip. Southwest has been scored 8.0/10 in 4,238 reviews.

North Conway

Boothbay Harbor

Jackson

Conway

Freeport

Lewiston

Brunswick

Bartlett

Auburn

Gorham

Intervale

Windham

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

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.

Start using Trips

Find my bookings

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

1 adult

Wed 12/3

Wed 12/10

Email me momondo's favorite deals

By creating a price alert you accept our terms of use and privacy policy.

Find better results for your trip to the United States

Airports servicing Maine

Rockland Knox County Regional Airport

Popular cities in the United States

Flights to New Yorkfrom $49

Flights to Los Angelesfrom $49

Flights to Miamifrom $49

Flights to Chicagofrom $54

Flights to Orlandofrom $47

Flights to Las Vegasfrom $49

Flights to San Franciscofrom $54

Flights to Washington, D.C.from $54

Flights to Bostonfrom $40

Flights to Atlantafrom $40

Flights to Dallasfrom $49

Flights to Seattlefrom $68

Cheap flights from St. Louis to Portland from $146

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 Portland departing on 12/12. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.

Big names and deals

Big names and deals

Filter for what you want

Filter for what you want

Trusted and free

Trusted and free

Price Alerts

Price Alerts

Find the cheapest flights from St. Louis to Portland

Cheap round-trip flights

Cheap one-way flights

Cheap last minute flights

Delta flights from St. Louis to Portland, Maine

Our best Delta deals on St. Louis to Portland, Maine flight tickets

Southwest flights from St. Louis to Portland, Maine

Our best Southwest deals on St. Louis to Portland, Maine flight tickets

momondo Fare Finder

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

See travel insights to Portland from

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?

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

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

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

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

What is the cheapest airline that flies from Lambert-St Louis to Portland?

United Airlines, Southwest, and Delta are the most popular carriers operating from Lambert-St Louis to Portland

What airlines fly to Portland, Maine?

Which airport is the most popular layover for flights between St. Louis and Portland, Maine?

Detroit (DTW) was the most common stop: 75% of momondo users choosing 1-stop flights on this route connected there.

Which layover airport offers the lowest fares from St. Louis to Portland, Maine?

Flights via Atlanta (ATL) offer the lowest average round-trip price of $387.

Which layover airport has the shortest travel time from St. Louis to Portland, Maine?

Flights connecting via Detroit (DTW) have the shortest average one-way travel time: 4h 33m.

Which layover airport has the shortest connection time from St. Louis to Portland, Maine?

Detroit (DTW) has the shortest average layover time for this route: 0h 56m.

How many flights depart from St. Louis to Portland, Maine on average per week?

The number of flights available between St. Louis and Portland, Maine is 3 per week as of November 2025. The most frequent departure day is Thu, with 33% of weekly flights leaving on this day.

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

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

Direct flights

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

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

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?

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

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

Southwest Flights From St. Louis to Portland, Maine

Traveling to a place near Portland?

Why use momondo?

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

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

How can momondo help me find flights 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?

An easier way to manage your Portland, Maine trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

Find better results for your trip to the United States

Airports servicing Maine