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$493+ Cheap flights from St. Louis (STL) to Porto (OPO)

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 2/4. Fares are subject to change and may not be available on all flights or dates of travel.
STL — OPO
Jan 22 — Jan 291
Thu 1/22
Thu 1/29
1 adult, Economy
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Cheap flight deals from St. Louis to Porto

Best flights from St. Louis to Porto
Discover carefully curated flight deals from St. Louis to Porto that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated December 23, 2025.

This Air France deal was found by Cheapflights users on 12/21. 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 Air France is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 2/49:59 amSTL - OPO
2 stops18h 31mMultiple Airlines
Wed 2/114:10 pmOPO - STL
2 stops31h 32mMultiple Airlines
Deal found 12/21$493
This United Airlines deal was found by Cheapflights users on 12/20. 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.
Wed 2/410:10 amSTL - OPO
2 stops23h 15mUnited Airlines
Sun 2/812:30 pmOPO - STL
2 stops56h 00mUnited Airlines
Deal found 12/20$527
This FlightHub deal was found by Cheapflights users on 12/21. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 1/161:15 pmSTL - OPO
2 stops27h 10mLufthansa
Tue 1/206:00 amOPO - STL
2 stops23h 59mLufthansa
Deal found 12/21$687
This Lufthansa deal was found by Cheapflights users on 12/22. 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.
Wed 1/143:50 pmSTL - OPO
1 stop13h 50mLufthansa
Sun 1/186:00 amOPO - STL
1 stop13h 55mLufthansa
Deal found 12/22$730
This American Airlines deal was found by Cheapflights users on 12/21. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 3/1311:22 amSTL - OPO
2 stops15h 18mAmerican Airlines
Sat 3/2112:25 pmOPO - STL
2 stops28h 04mAmerican Airlines
Deal found 12/21$1,466
This Air Canada deal was found by Cheapflights users on 12/21. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 1/161:15 pmSTL - OPO
3 stops16h 55mMultiple Airlines
Tue 1/206:00 amOPO - STL
2 stops39h 29mMultiple Airlines
Deal found 12/21$1,346

Find flight deals from St. Louis to Porto

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Porto (OPO). 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 December 23, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$493
(Air France)

Popular in

July

Cheapest in

February
Provider with most accurate pricing for Lambert-St Louis-Porto flight deals.
Search Deals
Provider most trusted by Cheapflights users for Lambert-St Louis-Porto flights.
Search Deals
From Lambert-St Louis to Porto
Search Deals
Highest demand for flights based on searches. 20% potential increase in price ($262 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($34 potential savings vs. average RT price).
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Cheapflights Fare Finder

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

Fly from

St. Louis

Fly to

Porto

Route

Depart

Return

Price

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Wed 2/4

9:59 am-10:30 am

2 stops18h 31m

Porto

Wed 2/11

4:10 pm-5:42 pm

2 stops31h 32m

$493

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Wed 2/4

10:10 am-3:25 pm

2 stops23h 15m

Porto

Sun 2/8

12:30 pm-2:30 pm

2 stops56h 00m

$527

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Fri 1/16

1:15 pm-10:25 pm

2 stops27h 10m

Porto

Tue 1/20

6:00 am-11:59 pm

2 stops23h 59m

$687

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Wed 1/14

3:50 pm-11:40 am

1 stop13h 50m

Porto

Sun 1/18

6:00 am-1:55 pm

1 stop13h 55m

$730

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Fri 1/16

1:15 pm-12:10 pm

3 stops16h 55m

Porto

Tue 1/20

6:00 am-3:29 pm

2 stops39h 29m

$1,346

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Fri 3/13

11:22 am-7:40 am

2 stops15h 18m

Porto

Sat 3/21

12:25 pm-11:29 am

2 stops28h 04m

$1,466

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/21

Compare providers for flights from St. Louis to Porto

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 St. Louis to Porto in December.
ProviderPrice AccuracyTrust Score*
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice Accuracy3 starsTrust Score*3 stars
OvagoPrice Accuracy2 starsTrust Score*2 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 St. Louis-Porto flights, users find the pricing of eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on St. Louis-Porto flight deals on Cheapflights vs. eDreams >95% of the time. Price accuracy is based on data collected from St. Louis-Porto flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on St. Louis-Porto flights, Cheapflights users trust eDreams the most. eDreams 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 St. Louis-Porto 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 St. Louis to Porto

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

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

Find hourly flight availability from St. Louis to Porto. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated December 23, 2025.

Unlike in the evening, when flights are generally more expensive, you can save up to 39% on flights from St. Louis to Porto by exploring options for tickets at noon.

Reviews of airlines servicing Porto

Get insights into the airlines that provide service to Porto. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Porto. Reviews last updated December 23, 2025.
Read reviews from past customers who have flown Delta, United Airlines, and Air Canada from St. Louis to Porto. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
7.9
Good
8,014 reviews

Boarding

8.1

Food

7.3

Comfort

7.9

Entertainment

7.9

Overall

7.9

Crew

8.5

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
Delta
7.9
Good
8,014 reviews
Delta
7.9
Good
8,014 reviews

Boarding

8.1

Food

7.3

Comfort

7.9

Entertainment

7.9

Overall

7.9

Crew

8.5

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
United Airlines
7.4
Good
9,105 reviews
Delta
7.9
Good
8,014 reviews

Boarding

8.1

Food

7.3

Comfort

7.9

Entertainment

7.9

Overall

7.9

Crew

8.5

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
Air Canada
7.1
Good
10,551 reviews
Delta
7.9
Good
8,014 reviews

Boarding

8.1

Food

7.3

Comfort

7.9

Entertainment

7.9

Overall

7.9

Crew

8.5

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
Lufthansa
6.8
Okay
7,649 reviews
Delta
7.9
Good
8,014 reviews

Boarding

8.1

Food

7.3

Comfort

7.9

Entertainment

7.9

Overall

7.9

Crew

8.5

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.

Related info for your journey

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

  • How long is the flight from St. Louis to Porto?

    There are many flights that can get you from St. Louis to Porto in 23h 15m. Fly via United Airlines or Lufthansa to get the fastest option. Airlines will cover a distance of 4154 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • What are the cheapest airlines flying from St. Louis to Porto round-trip?

    Lufthansa, at $520, was found to be the cheapest airline from St. Louis to Porto.Alternate airlines to your destination round-trip include Delta and United Airlines. Users have found that Lufthansa is 50% cheaper than the other options available to this destination.

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

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

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

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

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

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

See more FAQs

Traveling to a place near Porto?

Book flights to Porto if you plan to visit one of these locations
Aveiro
Arcos de Valdevez
Coimbra
Vila Nova de Gaia

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Alternative routes for St. Louis to Porto

See prices for flight routes from nearby airports that may be better suited for you.
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Top 4 airlines flying from St. Louis to Porto

Discover the top 4 airlines that operate flights from St. Louis to Porto. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated December 23, 2025.
AirlineCheapestAverageFlexibilityOn-time
LufthansaCheapest$520Average$1,207FlexibilityNo cancel feeOn-time76%
DeltaCheapest$713Average$963FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$760Average$1,114FlexibilityNo cancel feeOn-time69%
Air CanadaCheapest$787Average$1,005FlexibilityNo cancel feeOn-time67%

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