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

There are many flights that can get you from St. Louis to Porto in 18h 31m. Fly via Delta to get the fastest option. Airlines will cover a distance of 4154 mi.

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

Lufthansa, at $549, 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 47% cheaper than the other options available to this destination.

In terms of precipitation, rainfall in Porto ranges from 0.7 - 7.7 inches per month. December is typically the wettest month, when rainfall can reach 7.7 in. July is typically the driest time to visit Porto when rainfall is around 0.7 in.

If weather is an important factor for your trip to Porto, 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 68.0 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 48.2 F).

What are the most popular airlines that fly from St. Louis to Porto?

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

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.

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.

$492+ Flights from St. Louis to Porto

Home Search by date Vacation packages Hotels Flight deals Car rental Travel tips & news

Find cheap flights from St. Louis to Porto with Cheapflights

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.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap flight deals from St. Louis to Porto

Cheapest flights from St. Louis to Porto
Explore the most affordable flight options available from St. Louis to Porto. Find the lowest fares from popular airlines and budget airlines, with prices last updated on December 4, 2025.

Tue 12/306:35 pmSTL - OPO

2 stops45h 50mLufthansa

Tue 1/64:00 pmOPO - STL

2 stops37h 59mLufthansa

Deal found 12/3

$1,301

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 4, 2025.

Mon 2/99:59 amSTL - OPO

2 stops18h 31mDelta

Mon 2/2311:15 amOPO - STL

2 stops39h 28mDelta

Deal found 12/4

$492

Wed 2/119:57 amSTL - OPO

2 stops23h 28mUnited Airlines

Fri 2/206:00 amOPO - STL

2 stops21h 00mUnited Airlines

Deal found 12/4

$503

Tue 2/106:25 amSTL - OPO

2 stops22h 05mDelta

Thu 2/195:00 amOPO - STL

2 stops21h 43mDelta

Deal found 12/4

$492

Sat 1/179:57 amSTL - OPO

2 stops19h 43mUnited Airlines

Sat 1/246:00 amOPO - STL

2 stops22h 00mUnited Airlines

Deal found 12/3

$503

Tue 2/106:25 amSTL - OPO

2 stops22h 05mDelta

Mon 2/2311:15 amOPO - STL

2 stops38h 54mDelta

Deal found 12/4

$492

Fri 1/2311:20 amSTL - OPO

2 stops18h 20mUnited Airlines

Tue 1/276:00 amOPO - STL

2 stops22h 58mUnited Airlines

Deal found 12/3

$503

Sun 2/86:00 amSTL - OPO

2 stops22h 30mDelta

Fri 2/205:00 amOPO - STL

2 stops35h 43mDelta

Deal found 12/4

$492

Wed 2/119:57 amSTL - OPO

2 stops23h 28mUnited Airlines

Thu 2/196:00 amOPO - STL

2 stops21h 00mUnited Airlines

Deal found 12/4

$503

Sun 2/87:10 amSTL - OPO

2 stops21h 20mDelta

Thu 2/195:00 amOPO - STL

2 stops21h 43mDelta

Deal found 12/4

$492

Mon 2/96:25 amSTL - OPO

2 stops22h 05mDelta

Fri 2/205:00 amOPO - STL

2 stops35h 43mDelta

Deal found 12/4

$492

Fri 2/66:30 amSTL - OPO

2 stops23h 10mUnited Airlines

Tue 2/106:00 amOPO - STL

2 stops35h 02mUnited Airlines

Deal found 12/2

$591

Last-minute flights from St. Louis to Porto
Discover last-minute flight deals from St. Louis to Porto. Data last updated December 4, 2025 and is based on user searches.

Tue 12/306:35 pmSTL - OPO

2 stops45h 50mLufthansa

Tue 1/64:00 pmOPO - STL

2 stops37h 59mLufthansa

Deal found 12/3

$1,301

Sat 1/179:57 amSTL - OPO

2 stops19h 43mUnited Airlines

Sat 1/246:00 amOPO - STL

2 stops22h 00mUnited Airlines

Deal found 12/3

$503

Find flight deals from St. Louis to Porto

Most accurate provider	eDreams 3 stars
Most trusted provider	eDreams 3 stars
Round-trip from	$485 (American Airlines)
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. 19% potential increase in price ($260 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 3% potential price decrease ($35 potential savings vs. average RT price).

Search Deals

Fly from

Fly to

Route

Depart

Return

Price

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Mon 2/9

9:59 am-10:30 am

2 stops18h 31m

Porto

Mon 2/23

11:15 am-8:43 pm

2 stops39h 28m

$492

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Tue 2/10

6:25 am-10:30 am

2 stops22h 05m

Porto

Thu 2/19

5:00 am-8:43 pm

2 stops21h 43m

$492

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Tue 2/10

6:25 am-10:30 am

2 stops22h 05m

Porto

Mon 2/23

11:15 am-8:09 pm

2 stops38h 54m

$492

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Sun 2/8

6:00 am-10:30 am

2 stops22h 30m

Porto

Fri 2/20

5:00 am-10:43 am

2 stops35h 43m

$492

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Sun 2/8

7:10 am-10:30 am

2 stops21h 20m

Porto

Thu 2/19

5:00 am-8:43 pm

2 stops21h 43m

$492

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Mon 2/9

6:25 am-10:30 am

2 stops22h 05m

Porto

Fri 2/20

5:00 am-10:43 am

2 stops35h 43m

$492

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Wed 2/11

9:57 am-3:25 pm

2 stops23h 28m

Porto

Fri 2/20

6:00 am-9:00 pm

2 stops21h 00m

$503

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Sat 1/17

9:57 am-11:40 am

2 stops19h 43m

Porto

Sat 1/24

6:00 am-10:00 pm

2 stops22h 00m

$503

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Fri 1/23

11:20 am-11:40 am

2 stops18h 20m

Porto

Tue 1/27

6:00 am-10:58 pm

2 stops22h 58m

$503

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Wed 2/11

9:57 am-3:25 pm

2 stops23h 28m

Porto

Thu 2/19

6:00 am-9:00 pm

2 stops21h 00m

$503

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/4

Showing 1-10 of 11 results

Compare providers for flights from St. Louis to Porto

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.

Provider	Price Accuracy	Trust Score*
FlightHub	Price Accuracy3 stars	Trust Score*1 star
eDreams	Price Accuracy3 stars	Trust Score*3 stars
Ovago	Price Accuracy2 stars	Trust 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?

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

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

8,011 reviews

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

8,011 reviews

Delta

7.9

Good

8,011 reviews

Reviews

1 / 20

6.0

Good

Jim,Nov 2025

AVL - ATL

United Airlines

7.4

Good

9,066 reviews

Delta

7.9

Good

8,011 reviews

Reviews

1 / 20

6.0

Good

Jim,Nov 2025

AVL - ATL

Air Canada

7.1

Good

10,500 reviews

Delta

7.9

Good

8,011 reviews

Reviews

1 / 20

6.0

Good

Jim,Nov 2025

AVL - ATL

Lufthansa

6.8

Okay

7,612 reviews

Delta

7.9

Good

8,011 reviews

Reviews

1 / 20

6.0

Good

Jim,Nov 2025

AVL - ATL

Related info for your journey

How long is the flight from St. Louis to Porto?
There are many flights that can get you from St. Louis to Porto in 18h 31m. Fly via Delta to get the fastest option. Airlines will cover a distance of 4154 mi.
What are the cheapest airlines flying from St. Louis to Porto round-trip?
Lufthansa, at $549, 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 47% 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

Aveiro

Arcos de Valdevez

Coimbra

Vila Nova de Gaia

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for St. Louis to Porto

St. Louis to Lisbon flights

Kansas City to Lisbon flights

Kansas City to Porto flights

Kansas City to Ponta Delgada flights

Kansas City to Lajes flights

St. Louis to Lajes flights

Other flights to Porto

Top 4 airlines flying from St. Louis to Porto

Airline	Cheapest	Average	Flexibility	On-time
Lufthansa	Cheapest$549	Average$1,277	FlexibilityNo cancel fee	On-time76%
Delta	Cheapest$713	Average$963	FlexibilityNo cancel fee	On-timeN/A
United Airlines	Cheapest$760	Average$1,114	FlexibilityNo cancel fee	On-time69%
Air Canada	Cheapest$787	Average$1,005	FlexibilityNo cancel fee	On-time67%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.

$492+ 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 2/9. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from St. Louis to Porto with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheap flight deals from St. Louis to Porto

Cheapest flights from St. Louis to PortoExplore the most affordable flight options available from St. Louis to Porto. Find the lowest fares from popular airlines and budget airlines, with prices last updated on December 4, 2025.

Explore the most affordable flight options available from St. Louis to Porto. Find the lowest fares from popular airlines and budget airlines, with prices last updated on December 4, 2025.

Find flight deals from St. Louis to Porto

Most accurate provider

Most trusted provider

Round-trip from

Popular in

Cheapest in

Cheapflights Fare Finder

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

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.

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.

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?

Reviews of airlines servicing Porto

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.

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?

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

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

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

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

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 St. Louis to Porto

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

Top 4 airlines flying from St. Louis to Porto

100% Free

Book with Flexibility

Travel Smart

Cheapest flights from St. Louis to Porto
Explore the most affordable flight options available from St. Louis to Porto. Find the lowest fares from popular airlines and budget airlines, with prices last updated on December 4, 2025.