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$540+ 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 1/6. Fares are subject to change and may not be available on all flights or dates of travel.
OPO — STL
Aug 19 — Aug 261
Tue 8/19
Tue 8/26
1 adult, Economy
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Cheap flight deals from Porto to St. Louis

Discover tips and strategies to find the most affordable flight options for your journey from Porto (OPO) to St. Louis (STL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated August 14, 2025.

Round-trip from

$838
(United Airlines)

One-way from

$540
(Kiwi.com)
From Porto to Lambert-St Louis
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One-way flight from Porto to Lambert-St Louis
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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 August 14, 2025.

This Lufthansa deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Lufthansa is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/96:00 amOPO - STL
2 stops15h 44mMultiple Airlines
Tue 9/167:08 amSTL - OPO
1 stop20h 37mMultiple Airlines
Deal found 8/13$824
This United Airlines deal was found by Cheapflights users on 8/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/912:50 pmOPO - STL
1 stop13h 07mUnited Airlines
Tue 9/165:22 pmSTL - OPO
1 stop10h 23mUnited Airlines
Deal found 8/12$846
This United Airlines deal was found by Cheapflights users on 8/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/266:00 amOPO - STL
2 stops40h 32mUnited Airlines
Fri 10/33:23 pmSTL - OPO
2 stops37h 52mUnited Airlines
Deal found 8/12$918
This United Airlines deal was found by Cheapflights users on 8/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/2612:05 pmOPO - STL
2 stops32h 28mUnited Airlines
Sat 8/305:22 pmSTL - OPO
1 stop31h 33mUnited Airlines
Deal found 8/11$937
This Lufthansa deal was found by Cheapflights users on 8/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Lufthansa is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/266:00 amOPO - STL
2 stops15h 44mLufthansa
Fri 10/33:30 pmSTL - OPO
1 stop25h 15mLufthansa
Deal found 8/12$953
This Lufthansa deal was found by Cheapflights users on 8/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Lufthansa is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/264:35 pmOPO - STL
1 stop26h 55mLufthansa
Sat 8/3011:27 amSTL - OPO
1 stop13h 28mLufthansa
Deal found 8/11$972
This Mytrip deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/276:25 amOPO - STL
2 stops19h 32mMultiple Airlines
Sat 10/41:30 pmSTL - OPO
3 stops25h 50mMultiple Airlines
Deal found 8/13$1,037
This Lufthansa deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Lufthansa is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/2712:05 pmOPO - STL
1 stop31h 25mLufthansa
Sat 10/412:25 pmSTL - OPO
2 stops16h 50mLufthansa
Deal found 8/13$1,048
This Trip.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/2712:35 pmOPO - STL
1 stop17h 12mUnited Airlines
Sat 10/47:50 amSTL - OPO
1 stop19h 55mUnited Airlines
Deal found 8/13$1,117
This Mytrip deal was found by Cheapflights users on 8/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/266:00 amOPO - STL
2 stops19h 38mMultiple Airlines
Fri 10/34:05 pmSTL - OPO
3 stops22h 35mMultiple Airlines
Deal found 8/12$1,133

Cheapflights Fare Finder

 
Customize your flight search to find flights from Porto to St. Louis 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, Cheapflights users made 2,558,603 searches. Data last updated August 14, 2025.
Use the filters below to find and compare flights from Porto to St. Louis that are best for you.

Fly from

Porto

Fly to

St. Louis

Route

Depart

Return

Price

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Tue 9/9

6:00 am-3:44 pm

2 stops15h 44m

Lambert-St Louis

Tue 9/16

7:08 am-9:45 am

1 stop20h 37m

$824

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Tue 9/9

6:00 am-3:44 pm

2 stops15h 44m

Lambert-St Louis

Tue 9/16

12:35 pm-9:45 am

2 stops15h 10m

$838

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Fri 2/6

4:15 pm-9:10 pm

2 stops34h 55m

Lambert-St Louis

Sun 2/8

3:50 pm-3:15 pm

1 stop17h 25m

$851

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Tue 1/6

6:55 am-11:01 am

3 stops58h 06m

$540

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Wed 10/29

6:00 am-2:55 pm

1 stop13h 55m

$704

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Wed 10/29

8:20 am-8:26 pm

2 stops17h 06m

$721

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Tue 1/6

12:30 pm-1:55 pm

1 stop31h 25m

$809

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Tue 1/6

6:05 am-11:10 pm

2 stops23h 05m

$818

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Sun 1/4

8:40 pm-5:58 pm

2 stops27h 18m

$838

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/12

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.

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.

  • 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

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
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Fairview Heights
Maryland Heights
Collinsville
Eureka
St. Peters
Glencoe
Alton
Chesterfield
Farmington
Festus

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