What are the cheapest airlines to fly from Porto to St. Louis one-way?

To fly one-way, consider booking your trip with British Airways, which is currently one of the cheapest options available, starting at $709. Lufthansa flights start at $736 while deals on United Airlines start at $1,351 one-way.

What is the cheapest month to book a flight from Porto to St. Louis?

Currently, August is the cheapest month in which you can book a flight from Porto to St. Louis (average of $311). Flying from Porto 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 OPO to STL?

When flying from Porto to St. Louis, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

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

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

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

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

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

Yes. Cheapflights offers flight deals from Porto 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.

$662+ Flights from Porto to St. Louis

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Cheap flight deals from Porto to St. Louis

Round-trip from	$811 (United Airlines)
One-way from	$662 (Mytrip)

From Porto to Lambert-St Louis

Search Deals

One-way flight from Porto to Lambert-St Louis

Search Deals

Find flight deals from Porto to St. Louis

Cheapest flights from Porto to St. Louis
Explore the most affordable flight options available from Porto to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 12, 2025.

Sat 8/306:00 amOPO - STL

2 stops36h 25mUnited Airlines

Mon 9/86:15 amSTL - OPO

2 stops21h 20mUnited Airlines

Deal found 6/10

$811

Tue 6/176:15 amOPO - STL

2 stops17h 04mDelta

Tue 7/86:04 pmSTL - OPO

2 stops15h 31mDelta

Deal found 6/10

$855

Sat 9/2012:05 pmOPO - STL

1 stop31h 25mLufthansa

Sat 10/412:25 pmSTL - OPO

2 stops16h 50mLufthansa

Deal found 6/10

$869

Sat 9/208:15 amOPO - STL

2 stops18h 17mAmerican Airlines

Sat 10/410:25 amSTL - OPO

2 stops19h 15mAmerican Airlines

Deal found 6/10

$901

Sat 8/304:35 pmOPO - STL

1 stop26h 55mMultiple Airlines

Mon 9/81:30 pmSTL - OPO

1 stop14h 05mMultiple Airlines

Deal found 6/10

$957

Sun 7/2712:20 pmOPO - STL

2 stops17h 31mBritish Airways

Sun 8/38:01 pmSTL - OPO

2 stops13h 54mBritish Airways

Deal found 6/12

$1,085

Sun 7/275:00 amOPO - STL

2 stops21h 36mKLM

Sun 8/35:45 pmSTL - OPO

2 stops56h 40mKLM

Deal found 6/12

$1,249

Sun 7/611:20 amOPO - STL

1 stop15h 30mAir Canada

Mon 7/71:30 pmSTL - OPO

1 stop14h 05mAir Canada

Deal found 6/10

$2,089

Best flights from Porto to St. Louis
Discover carefully curated flight deals from Porto to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 12, 2025.

Sat 8/306:00 amOPO - STL

2 stops36h 25mUnited Airlines

Mon 9/86:15 amSTL - OPO

2 stops21h 20mUnited Airlines

Deal found 6/10

$811

Sat 9/2012:05 pmOPO - STL

1 stop31h 25mLufthansa

Sat 10/412:25 pmSTL - OPO

2 stops16h 50mLufthansa

Deal found 6/10

$869

Sat 9/208:15 amOPO - STL

2 stops18h 17mAmerican Airlines

Sat 10/410:25 amSTL - OPO

2 stops19h 15mAmerican Airlines

Deal found 6/10

$901

Sat 8/304:35 pmOPO - STL

1 stop26h 55mMultiple Airlines

Mon 9/81:30 pmSTL - OPO

1 stop14h 05mMultiple Airlines

Deal found 6/10

$957

Sun 7/2712:20 pmOPO - STL

2 stops17h 31mBritish Airways

Sun 8/38:01 pmSTL - OPO

2 stops13h 54mBritish Airways

Deal found 6/12

$1,085

Thu 6/266:30 amOPO - STL

2 stops16h 49mDelta

Mon 6/3010:30 amSTL - OPO

2 stops23h 05mDelta

Deal found 6/10

$1,209

Sun 7/275:00 amOPO - STL

2 stops21h 36mKLM

Sun 8/35:45 pmSTL - OPO

2 stops56h 40mKLM

Deal found 6/12

$1,249

Sun 7/611:20 amOPO - STL

1 stop15h 30mAir Canada

Mon 7/71:30 pmSTL - OPO

1 stop14h 05mAir Canada

Deal found 6/10

$2,089

Last-minute flights from Porto to St. Louis
Discover last-minute flight deals from Porto to St. Louis. Data last updated June 12, 2025 and is based on user searches.

Tue 6/176:15 amOPO - STL

2 stops17h 04mDelta

Tue 7/86:04 pmSTL - OPO

2 stops15h 31mDelta

Deal found 6/10

$855

Tue 6/1712:50 pmOPO - STL

1 stop13h 08mUnited Airlines

Tue 7/88:00 amSTL - OPO

2 stops19h 45mUnited Airlines

Deal found 6/10

$1,050

Tue 6/178:25 amOPO - STL

2 stops34h 11mMultiple Airlines

Tue 7/85:00 amSTL - OPO

3 stops29h 40mMultiple Airlines

Deal found 6/10

$1,169

Thu 6/266:00 amOPO - STL

3 stops41h 04mMultiple Airlines

Mon 6/301:30 pmSTL - OPO

3 stops26h 05mMultiple Airlines

Deal found 6/11

$1,076

Sun 7/611:20 amOPO - STL

1 stop15h 30mAir Canada

Mon 7/71:30 pmSTL - OPO

1 stop14h 05mAir Canada

Deal found 6/10

$2,089

Sun 7/2712:20 pmOPO - STL

2 stops17h 31mBritish Airways

Sun 8/38:01 pmSTL - OPO

2 stops13h 54mBritish Airways

Deal found 6/12

$1,085

Sun 7/275:00 amOPO - STL

2 stops21h 36mKLM

Sun 8/35:45 pmSTL - OPO

2 stops56h 40mKLM

Deal found 6/12

$1,249

One-way flights from Porto to St. Louis
Search for one-way flight options from Porto to St. Louis. Find affordable one-way fares based on user searches. Data last updated June 12, 2025.

Wed 8/136:00 amOPO - STL

3 stops42h 32mMultiple Airlines

Deal found 6/11

$662

Wed 10/298:20 amOPO - STL

2 stops15h 48mBritish Airways

Deal found 6/10

$709

Wed 10/296:00 amOPO - STL

1 stop13h 55mLufthansa

Deal found 6/10

$736

Sun 7/69:15 amOPO - STL

1 stop13h 00mUnited Airlines

Deal found 6/10

$1,351

Sat 7/53:05 amOPO - STL

2 stops42h 11mAir Canada

Deal found 6/10

$1,963

Cheapflights Fare Finder

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

Fly from

Fly to

Route

Depart

Return

Price

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Sat 8/30

6:00 am-12:25 pm

2 stops36h 25m

Lambert-St Louis

Mon 9/8

6:15 am-9:35 am

2 stops21h 20m

$811

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Sat 9/20

12:05 pm-1:30 pm

1 stop31h 25m

Lambert-St Louis

Sat 10/4

12:25 pm-11:15 am

2 stops16h 50m

$869

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Sat 9/20

8:15 am-8:32 pm

2 stops18h 17m

Lambert-St Louis

Sat 10/4

10:25 am-11:40 am

2 stops19h 15m

$901

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Sat 8/30

4:35 pm-1:30 pm

1 stop26h 55m

Lambert-St Louis

Mon 9/8

1:30 pm-9:35 am

1 stop14h 05m

$957

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Sun 7/27

12:20 pm-11:51 pm

2 stops17h 31m

Lambert-St Louis

Sun 8/3

8:01 pm-3:55 pm

2 stops13h 54m

$1,085

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Thu 6/26

6:30 am-5:19 pm

2 stops16h 49m

Lambert-St Louis

Mon 6/30

10:30 am-3:35 pm

2 stops23h 05m

$1,209

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Sun 7/27

5:00 am-8:36 pm

2 stops21h 36m

Lambert-St Louis

Sun 8/3

5:45 pm-8:25 am

2 stops56h 40m

$1,249

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Sun 7/6

11:20 am-8:50 pm

1 stop15h 30m

Lambert-St Louis

Mon 7/7

1:30 pm-9:35 am

1 stop14h 05m

$2,089

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Wed 8/13

6:00 am-6:32 pm

3 stops42h 32m

$662

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Wed 10/29

8:20 am-7:08 pm

2 stops15h 48m

$709

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/11

Showing 1-10 of 13 results

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

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Porto 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 Porto to St. Louis

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

Peruse reviews from past customers who have flown with Delta, KLM and United Airlines from Porto to St. Louis to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.

Delta

8.0

Very good

7,946 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

Delta

8.0

Very good

7,946 reviews

Delta

8.0

Very good

7,946 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

KLM

7.8

Good

1,358 reviews

Delta

8.0

Very good

7,946 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

United Airlines

7.4

Good

8,790 reviews

Delta

8.0

Very good

7,946 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

American Airlines

7.2

Good

10,000 reviews

Delta

8.0

Very good

7,946 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

Air Canada

7.1

Good

9,537 reviews

Delta

8.0

Very good

7,946 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

Related info for your journey

What are the cheapest airlines to fly from Porto to St. Louis one-way?
To fly one-way, consider booking your trip with British Airways, which is currently one of the cheapest options available, starting at $709. Lufthansa flights start at $736 while deals on United Airlines start at $1,351 one-way.
Can I find deals for flights from Porto to St. Louis that include hotel bookings?
Yes. In addition to deals on Porto to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Porto to St. Louis?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Porto to St. Louis.
Can I find deals for business class flights from Porto to St. Louis?
Yes. Cheapflights offers flight deals from Porto 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 Porto to St. Louis?
Currently, August is the cheapest month in which you can book a flight from Porto to St. Louis (average of $311). Flying from Porto 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

O'Fallon

Maryland Heights

Fairview Heights

Collinsville

Eureka

St. Peters

Glencoe

Festus

Alton

Farmington

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$662+ Cheap flights from Porto (OPO) to St. Louis (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 8/13. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Porto to St. Louis with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheap flight deals from Porto to St. Louis

Round-trip from

One-way from

Find flight deals from Porto to St. Louis

Cheapest flights from Porto to St. LouisExplore the most affordable flight options available from Porto to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 12, 2025.

Explore the most affordable flight options available from Porto to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 12, 2025.

Cheapflights Fare Finder

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

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

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

Cheapflights Insights

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

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

Peruse reviews from past customers who have flown with Delta, KLM and United Airlines from Porto to St. Louis to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.

Related info for your journey

Find useful and relevant information for your journey from Porto 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 to fly from Porto to St. Louis one-way?

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

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

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

What is the cheapest month to book a flight from Porto to St. Louis?

Traveling to a place near Porto?

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Porto to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.

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Book with Flexibility

Travel Smart

Cheapest flights from Porto to St. Louis
Explore the most affordable flight options available from Porto to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 12, 2025.