What are the cheapest airlines flying from Portland, Maine to St. Louis round-trip?

Flying on Frontier is currently your cheapest option to St. Louis, with prices starting at $268. Additional round-trip tickets that might be worth considering are offered by American Airlines and Delta, with the lowest prices starting at $291 and $322, respectively. Frontier is 38% cheaper than the average price of flights available within the next 90 days to this destination.

What are the cheapest airlines to fly from Portland, Maine to St. Louis one-way?

For one-way options, check prices for American Airlines. According to our data, you can fly for as low as $159. Users have also found prices from $162 and $444 on United Airlines and Southwest, respectively.

What is the cheapest day to fly from Portland, Maine to St. Louis?

Travelers seeking maximum savings on their Portland, Maine to St. Louis flight should consider departing on Thursday afternoons when fares are most often at their lowest. Sunday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

What are the most popular airlines that fly from Portland, Maine to St. Louis?

When booking a flight from Portland, Maine to St. Louis, you may want to consider flying on American Airlines, Delta or United Airlines as they are the most popular for this route.

What is the cheapest day to fly round-trip from Portland, Maine to St. Louis?

Departing on a Monday is a good option for securing a great price. You can expect to save up to 43% when planning your travel around this day of the week.

How far in advance should I book a flight from Portland, Maine to St. Louis?

To save up to 145% on this flight, we recommend booking at least 11 days prior to travel. The price may fluctuate and will likely increase closer to your departure date. Users on Cheapflights have found tickets from Portland, Maine to St. Louis from $228 1-2 weeks out and tickets from $639 for flights departing within the next 72 hours.

What is the cheapest month to fly from Portland, Maine to St. Louis?

Due to multiple factors, expect to potentially pay more when booking in December. For low rates, February can be a great choice for travel to St. Louis. Flights to St. Louis from Portland, Maine in February are about $436 on average during February, but can be found for as low as $213.

Most accurate provider : When it comes to deals on Portland, Maine-St. Louis flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Portland, Maine-St. Louis flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Portland, Maine-St. Louis flight searches over the past month and is updated monthly.

Most trusted provider : When it comes to deals on Portland, Maine-St. Louis flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Portland, Maine-St. Louis flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Can I find deals for flights from Portland to St. Louis that include hotel bookings?

Yes. In addition to deals on Portland to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from Portland to St. Louis?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Portland to St. Louis.

Can I find deals for business class flights from Portland to St. Louis?

Yes. Cheapflights offers flight deals from Portland to St. Louis by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$159+ Flights from Portland, ME to St. Louis

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1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

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Cheapflights Tip: The best prices from Portland to Lambert-St Louis are usually found in February or January, booked 10 days in advance, depart on a Tuesday or Friday and return on a Tuesday

Cheap flight deals from Portland to St. Louis

Most accurate provider	FlightHub 3 stars
Most trusted provider	FlightHub 3 stars
Round-trip from	$268 (Booking.com)
One-way from	$159 (American Airlines)
Popular in	December
Cheapest in	February
Average price	$451

Provider with most accurate pricing for Portland-Lambert-St Louis flight deals.

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Provider most trusted by Cheapflights users for Portland-Lambert-St Louis flights.

Search Deals

From Portland to Lambert-St Louis

Search Deals

One-way flight from Portland to Lambert-St Louis

Search Deals

Highest demand for flights based on searches. 2% potential increase in price ($8 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 2% potential price decrease ($10 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in March 2025

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Find flight deals from Portland to St. Louis

Cheapest flights from Portland to St. Louis
Explore the most affordable flight options available from Portland to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 25, 2025.

Sat 4/1210:12 amPWM - STL

1 stop14h 34mFrontier

Sun 4/134:57 pmSTL - PWM

1 stop20h 13mFrontier

Deal found 3/24

$268

Wed 5/2812:08 pmPWM - STL

1 stop12h 43mAmerican Airlines

Wed 6/41:59 pmSTL - PWM

1 stop8h 06mAmerican Airlines

Deal found 3/24

$291

Sat 5/105:00 pmPWM - STL

2 stops7h 26mDelta

Tue 5/135:40 pmSTL - PWM

1 stop5h 19mDelta

Deal found 3/24

$322

Tue 6/105:30 amPWM - STL

2 stops8h 05mSouthwest

Mon 6/165:05 pmSTL - PWM

1 stop6h 00mSouthwest

Deal found 3/24

$357

Wed 4/96:15 amPWM - STL

2 stops10h 32mUnited Airlines

Mon 4/148:00 amSTL - PWM

1 stop5h 53mUnited Airlines

Deal found 3/24

$374

Fri 5/96:16 pmPWM - STL

3 stops15h 59mMultiple Airlines

Sun 5/1110:10 amSTL - PWM

2 stops26h 57mMultiple Airlines

Deal found 3/24

$606

Best flights from Portland to St. Louis
Discover carefully curated flight deals from Portland to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated March 25, 2025.

Sat 4/1210:12 amPWM - STL

1 stop14h 34mFrontier

Sun 4/134:57 pmSTL - PWM

1 stop20h 13mFrontier

Deal found 3/24

$268

Wed 5/2812:08 pmPWM - STL

1 stop12h 43mAmerican Airlines

Wed 6/41:59 pmSTL - PWM

1 stop8h 06mAmerican Airlines

Deal found 3/24

$291

Sat 5/105:00 pmPWM - STL

2 stops7h 26mDelta

Tue 5/135:40 pmSTL - PWM

1 stop5h 19mDelta

Deal found 3/24

$322

Tue 6/105:30 amPWM - STL

2 stops8h 05mSouthwest

Mon 6/163:35 pmSTL - PWM

2 stops7h 30mSouthwest

Deal found 3/24

$362

Wed 4/96:15 amPWM - STL

2 stops10h 32mUnited Airlines

Mon 4/148:00 amSTL - PWM

1 stop5h 53mUnited Airlines

Deal found 3/24

$374

Fri 5/96:16 pmPWM - STL

3 stops15h 59mMultiple Airlines

Sun 5/1110:10 amSTL - PWM

2 stops26h 57mMultiple Airlines

Deal found 3/24

$606

Last-minute flights from Portland to St. Louis
Discover last-minute flight deals from Portland to St. Louis. Data last updated March 25, 2025 and is based on user searches.

Wed 4/96:15 amPWM - STL

2 stops10h 32mUnited Airlines

Tue 4/153:40 pmSTL - PWM

1 stop4h 55mUnited Airlines

Deal found 3/24

$374

Wed 4/96:15 amPWM - STL

2 stops8h 45mSouthwest

Sun 4/136:40 amSTL - PWM

1 stop4h 15mSouthwest

Deal found 3/24

$452

Sat 4/1210:12 amPWM - STL

1 stop14h 34mFrontier

Sun 4/134:57 pmSTL - PWM

1 stop20h 13mFrontier

Deal found 3/24

$268

Wed 4/1612:15 pmPWM - STL

1 stop9h 32mAmerican Airlines

Sat 4/196:15 amSTL - PWM

1 stop4h 45mAmerican Airlines

Deal found 3/23

$315

Wed 4/1611:40 amPWM - STL

2 stops7h 22mDelta

Sat 4/196:50 amSTL - PWM

1 stop3h 59mDelta

Deal found 3/23

$322

One-way flights from Portland to St. Louis
Search for one-way flight options from Portland to St. Louis. Find affordable one-way fares based on user searches. Data last updated March 25, 2025.

Wed 4/165:38 amPWM - STL

1 stop5h 14mAmerican Airlines

Deal found 3/23

$159

Wed 4/166:15 amPWM - STL

2 stops10h 32mUnited Airlines

Deal found 3/23

$162

Sun 6/2212:50 pmPWM - STL

2 stops10h 10mSouthwest

Deal found 3/24

$444

Cheapflights Fare Finder

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

Fly from

Fly to

Route

Depart

Return

Price

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sat 4/12

10:12 am-11:46 pm

1 stop14h 34m

Lambert-St Louis

Sun 4/13

4:57 pm-2:10 pm

1 stop20h 13m

$268

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 5/28

12:08 pm-11:51 pm

1 stop12h 43m

Lambert-St Louis

Wed 6/4

1:59 pm-11:05 pm

1 stop8h 06m

$291

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sat 5/10

5:00 pm-11:26 pm

2 stops7h 26m

Lambert-St Louis

Tue 5/13

5:40 pm-11:59 pm

1 stop5h 19m

$322

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Tue 6/10

5:30 am-12:35 pm

2 stops8h 05m

Lambert-St Louis

Mon 6/16

5:05 pm-12:05 am

1 stop6h 00m

$357

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 4/9

6:15 am-3:47 pm

2 stops10h 32m

Lambert-St Louis

Tue 4/15

3:40 pm-9:35 pm

1 stop4h 55m

$374

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Fri 5/9

6:16 pm-9:15 am

3 stops15h 59m

Lambert-St Louis

Sun 5/11

10:10 am-2:07 pm

2 stops26h 57m

$606

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 4/16

5:38 am-9:52 am

1 stop5h 14m

$159

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Wed 4/16

6:15 am-3:47 pm

2 stops10h 32m

$162

PortlandSt. Louis

PWM - STL

PWMSTL

Portland

Sun 6/22

12:50 pm-10:00 pm

2 stops10h 10m

$444

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/23

Compare providers for flights from Portland to St. Louis

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Portland to St. Louis in March.

Provider	Price Accuracy	Trust Score*
Expedia	Price Accuracy1 star	Trust Score*3 stars
FlightHub	Price Accuracy3 stars	Trust Score*3 stars
eDreams	Price Accuracy3 stars	Trust Score*3 stars
Gotogate	Price Accuracy3 stars	Trust Score*3 stars
Mytrip	Price Accuracy3 stars	Trust Score*3 stars
Flightnetwork	Price Accuracy2 stars	Trust Score*3 stars
Cheapfaremart	Price Accuracy-	Trust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

Most accurate provider: When it comes to deals on Portland, Maine-St. Louis flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Portland, Maine-St. Louis flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Portland, Maine-St. Louis flight searches over the past month and is updated monthly.
Most trusted provider: When it comes to deals on Portland, Maine-St. Louis flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Portland, Maine-St. Louis flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Portland to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Portland with our price prediction graph.

Estimated round-trip price

Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Portland to St. Louis

How far ahead should I book a flight from Portland, Maine to St. Louis?

The price you pay for your flight from Portland, Maine to St. Louis may vary depending on when you book. For the best chance of a lower fare, look to book 10 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

What is the cheapest month to book a flight from Portland, Maine to St. Louis?

Currently, August is the cheapest month in which you can book a flight from Portland, Maine to St. Louis (average of $311). Flying from Portland, Maine to St. Louis in March is currently the most expensive (average of $356). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from PWM to STL?

When flying from Portland, Maine to St. Louis, the time of day you fly usually plays a role in the price. Save by searching for a flight in the afternoon, which can drop the price by up to 28% versus a flight at noon.

Rainfall in St. Louis by month

In terms of precipitation, rainfall in St. Louis ranges from 2.2 - 4.7 inches per month. May is typically the wettest month, when rainfall can reach 4.7 in. February is typically the driest time to visit St. Louis when rainfall is around 2.2 in.

Temperature in St. Louis by month

If weather is an important factor for your trip to St. Louis, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 80.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 32.0 F).

Reviews of airlines servicing St. Louis

Southwest

8.0

Very good

4,272 reviews

Reviews

1 / 20

8.0

Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.

Southwest

8.0

Very good

4,272 reviews

Southwest

8.0

Very good

4,272 reviews

Reviews

1 / 20

8.0

Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.

Delta

8.0

Very good

7,890 reviews

Southwest

8.0

Very good

4,272 reviews

Reviews

1 / 20

8.0

Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.

United Airlines

7.4

Good

8,605 reviews

Southwest

8.0

Very good

4,272 reviews

Reviews

1 / 20

8.0

Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.

American Airlines

7.2

Good

10,000 reviews

Southwest

8.0

Very good

4,272 reviews

Reviews

1 / 20

8.0

Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.

Frontier

6.0

Okay

3,273 reviews

Southwest

8.0

Very good

4,272 reviews

Reviews

1 / 20

8.0

Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.

Related info for your journey

What are the cheapest airlines flying from Portland, Maine to St. Louis round-trip?
Flying on Frontier is currently your cheapest option to St. Louis, with prices starting at $268. Additional round-trip tickets that might be worth considering are offered by American Airlines and Delta, with the lowest prices starting at $291 and $322, respectively. Frontier is 38% cheaper than the average price of flights available within the next 90 days to this destination.
What are the cheapest airlines to fly from Portland, Maine to St. Louis one-way?
For one-way options, check prices for American Airlines. According to our data, you can fly for as low as $159. Users have also found prices from $162 and $444 on United Airlines and Southwest, respectively.
Can I find deals for flights from Portland to St. Louis that include hotel bookings?
Yes. In addition to deals on Portland to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Portland to St. Louis?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Portland to St. Louis.
Can I find deals for business class flights from Portland to St. Louis?
Yes. Cheapflights offers flight deals from Portland to St. Louis by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.
What is the cheapest month to book a flight from Portland, Maine to St. Louis?
Currently, August is the cheapest month in which you can book a flight from Portland, Maine to St. Louis (average of $311). Flying from Portland, Maine to St. Louis in March is currently the most expensive (average of $356). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Fenton

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Collinsville

Wentzville

Eureka

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Festus

Glencoe

Alton

Farmington

Chesterfield

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Other flights to St. Louis

Top 4 airlines flying from Portland to St. Louis

Airline	Cheapest	Average	Flexibility	On-time
American Airlines	Cheapest$308	Average$439	FlexibilityNo cancel fee	On-time71%
United Airlines	Cheapest$341	Average$478	FlexibilityNo cancel fee	On-time69%
Southwest	Cheapest$351	Average$416	FlexibilityNo cancel fee	On-time63%
Delta	Cheapest$361	Average$503	FlexibilityNo cancel fee	On-timeN/A

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$159+ Cheap flights from Portland, ME to St. Louis (PWM - STL)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 4/16. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Portland to St. Louis with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheapflights Tip: The best prices from Portland to Lambert-St Louis are usually found in February or January, booked 10 days in advance, depart on a Tuesday or Friday and return on a Tuesday

Cheap flight deals from Portland to St. Louis

Most accurate provider

Most trusted provider

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Find flight deals from Portland to St. Louis

Cheapest flights from Portland to St. LouisExplore the most affordable flight options available from Portland to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 25, 2025.

Explore the most affordable flight options available from Portland to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 25, 2025.

Cheapflights Fare Finder

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

Compare providers for flights from Portland to St. Louis

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Portland to St. Louis in March.

Best time to book a flight from Portland to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Portland with our price prediction graph.

Cheapflights Insights

Everything you need to know about your flight from Portland to St. Louis

How far ahead should I book a flight from Portland, Maine to St. Louis?

Use this chart to determine the optimal time to book a round-trip flight from Portland to St. Louis. Price data was last updated on March 21, 2025.

What is the cheapest month to book a flight from Portland, Maine to St. Louis?

What is the cheapest time of day to fly from PWM to STL?

Find hourly flight availability from Portland to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated March 25, 2025.

Rainfall in St. Louis by month

Plan your trip to St. Louis by taking into account the average rainfall totals by month.

Temperature in St. Louis by month

Plan your trip to St. Louis by taking into account the average temperature totals by month.

Reviews of airlines servicing St. Louis

Related info for your journey

Find useful and relevant information for your journey from Portland to St. Louis. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

What are the cheapest airlines flying from Portland, Maine to St. Louis round-trip?

What are the cheapest airlines to fly from Portland, Maine to St. Louis one-way?

Can I find deals for flights from Portland to St. Louis that include hotel bookings?

How can I find direct flights from Portland to St. Louis?

Can I find deals for business class flights from Portland to St. Louis?

What is the cheapest month to book a flight from Portland, Maine to St. Louis?

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Top 4 airlines flying from Portland to St. Louis

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Cheapest flights from Portland to St. Louis
Explore the most affordable flight options available from Portland to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 25, 2025.