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Cheap flights from St. Louis to Porto from $458

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Porto departing on 10/28. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
1 adult, Economy, 0 bags

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from St. Louis to Porto

Cheap round-trip flights

Enter your travel dates to find the best prices.
Iberia Logo
9:50 am - 11:45 amSTL  Lambert-St Louis-OPO Porto
19h 55m2 stops Boston Logan Intl Madrid Barajas
Iberia Logo
4:40 pm - 9:30 amOPO  Porto-STL Lambert-St Louis
22h 50m2 stops Madrid Barajas Dallas/Fort Worth
$736Iberia
Wed, Nov 25 - Wed, Dec 2
United Airlines Logo
7:30 am - 9:30 amSTL  Lambert-St Louis-OPO Porto
20h 00m1 stop Newark
United Airlines Logo
6:00 am - 9:13 pmOPO  Porto-STL Lambert-St Louis
21h 13m2 stops Frankfurt am Main Chicago O'Hare Intl
$745United Airlines
Mon, Dec 7 - Thu, Dec 10
United Airlines Logo
8:33 am - 9:30 amSTL  Lambert-St Louis-OPO Porto
18h 57m2 stops Chicago O'Hare Intl Newark
United Airlines Logo
6:00 am - 9:13 pmOPO  Porto-STL Lambert-St Louis
21h 13m2 stops Frankfurt am Main Chicago O'Hare Intl
$750United Airlines
Mon, Dec 7 - Thu, Dec 10
United Airlines Logo
5:20 pm - 9:30 amSTL  Lambert-St Louis-OPO Porto
10h 10m1 stop Newark
United Airlines Logo
12:35 pm - 11:25 pmOPO  Porto-STL Lambert-St Louis
16h 50m1 stop Newark
$754United Airlines
Mon, Dec 7 - Thu, Dec 10
Lufthansa Logo
6:50 pm - 11:55 pmSTL  Lambert-St Louis-OPO Porto
23h 05m2 stops Chicago O'Hare Intl Munich Franz Josef Strauss
Lufthansa Logo
6:00 am - 1:45 pmOPO  Porto-STL Lambert-St Louis
13h 45m1 stop Frankfurt am Main
$767Lufthansa
Wed, Nov 25 - Wed, Dec 2
Multiple Airlines Logo
4:05 pm - 12:50 pmSTL  Lambert-St Louis-OPO Porto
15h 45m2 stops Toronto Pearson Intl Munich Franz Josef Strauss
Multiple Airlines Logo
8:40 am - 3:09 pmOPO  Porto-STL Lambert-St Louis
36h 29m2 stops Zurich Toronto Pearson Intl
$792Multiple Airlines
Wed, Oct 28 - Thu, Apr 22
Multiple Airlines Logo
4:40 pm - 11:45 amSTL  Lambert-St Louis-OPO Porto
14h 05m1 stop Frankfurt am Main
Multiple Airlines Logo
8:40 am - 3:09 pmOPO  Porto-STL Lambert-St Louis
36h 29m2 stops Zurich Toronto Pearson Intl
$795Multiple Airlines
Wed, Oct 28 - Thu, Apr 22
Delta Logo
7:20 am - 10:35 amSTL  Lambert-St Louis-OPO Porto
21h 15m2 stops Atlanta Hartsfield-Jackson Paris Charles de Gaulle
Delta Logo
5:00 am - 4:54 pmOPO  Porto-STL Lambert-St Louis
17h 54m2 stops Amsterdam Schiphol Minneapolis St Paul
$801Delta
Fri, Jan 29 - Wed, Feb 3
Lufthansa Logo
4:40 pm - 3:20 pmSTL  Lambert-St Louis-OPO Porto
17h 40m1 stop Frankfurt am Main
Lufthansa Logo
4:35 pm - 1:25 pmOPO  Porto-STL Lambert-St Louis
26h 50m1 stop Frankfurt am Main
$806Lufthansa
Wed, Oct 28 - Thu, Apr 22
Lufthansa Logo
3:40 pm - 11:45 amSTL  Lambert-St Louis-OPO Porto
14h 05m1 stop Frankfurt am Main
Lufthansa Logo
6:00 am - 1:45 pmOPO  Porto-STL Lambert-St Louis
13h 45m1 stop Frankfurt am Main
$819Lufthansa
Wed, Nov 25 - Wed, Dec 2

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Iberia flights from St. Louis to Porto

Our best Iberia deals on St. Louis to Porto flight tickets
Iberia
Nov 25
STL9:50 amLambert-St Louis
19h 55m
2 stops
OPO11:45 amPorto
Dec 2
OPO4:40 pmPorto
22h 50m
2 stops
STL9:30 amLambert-St Louis
$736
Iberia
Aug 12
STL9:32 amLambert-St Louis
20h 13m
2 stops
OPO11:45 amPorto
Aug 14
OPO12:25 pmPorto
17h 17m
2 stops
STL11:42 pmLambert-St Louis
$1,625

United Airlines flights from St. Louis to Porto

Our best United Airlines deals on St. Louis to Porto flight tickets
United Airlines
Dec 7
STL7:30 amLambert-St Louis
20h 00m
1 stop
OPO9:30 amPorto
Dec 10
OPO6:00 amPorto
21h 13m
2 stops
STL9:13 pmLambert-St Louis
$745
United Airlines
Dec 7
STL8:33 amLambert-St Louis
18h 57m
2 stops
OPO9:30 amPorto
Dec 10
OPO6:00 amPorto
21h 13m
2 stops
STL9:13 pmLambert-St Louis
$750
United Airlines
Dec 7
STL5:20 pmLambert-St Louis
10h 10m
1 stop
OPO9:30 amPorto
Dec 10
OPO12:35 pmPorto
16h 50m
1 stop
STL11:25 pmLambert-St Louis
$754

momondo 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, momondo users made 832,500 searches. Data last updated August 8, 2026.
Use the filters below to find and compare flights from St. Louis to Porto that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisPorto

STL Lambert-St Louis - OPO Porto

STLOPO

Lambert-St Louis

Wed 11/25

9:50 am-11:45 am

2 stops19h 55m

Porto

Wed 12/2

4:40 pm-9:30 am

2 stops22h 50m

$736

St. LouisPorto

STL Lambert-St Louis - OPO Porto

STLOPO

Lambert-St Louis

Mon 12/7

7:30 am-9:30 am

1 stop20h 00m

Porto

Thu 12/10

6:00 am-9:13 pm

2 stops21h 13m

$745

St. LouisPorto

STL Lambert-St Louis - OPO Porto

STLOPO

Lambert-St Louis

Mon 12/7

8:33 am-9:30 am

2 stops18h 57m

Porto

Thu 12/10

6:00 am-9:13 pm

2 stops21h 13m

$750
Quickest round-trip

St. LouisPorto

STL Lambert-St Louis - OPO Porto

STLOPO

Lambert-St Louis

Mon 12/7

5:20 pm-9:30 am

1 stop10h 10m

Porto

Thu 12/10

12:35 pm-11:25 pm

1 stop16h 50m

$754

St. LouisPorto

STL Lambert-St Louis - OPO Porto

STLOPO

Lambert-St Louis

Wed 11/25

6:50 pm-11:55 pm

2 stops23h 05m

Porto

Wed 12/2

6:00 am-1:45 pm

1 stop13h 45m

$767

St. LouisPorto

STL Lambert-St Louis - OPO Porto

STLOPO

Lambert-St Louis

Wed 10/28

4:05 pm-12:50 pm

2 stops15h 45m

Porto

Thu 4/22

8:40 am-3:09 pm

2 stops36h 29m

$792

St. LouisPorto

STL Lambert-St Louis - OPO Porto

STLOPO

Lambert-St Louis

Wed 10/28

4:40 pm-11:45 am

1 stop14h 05m

Porto

Thu 4/22

8:40 am-3:09 pm

2 stops36h 29m

$795

St. LouisPorto

STL Lambert-St Louis - OPO Porto

STLOPO

Lambert-St Louis

Fri 1/29

7:20 am-10:35 am

2 stops21h 15m

Porto

Wed 2/3

5:00 am-4:54 pm

2 stops17h 54m

$801

St. LouisPorto

STL Lambert-St Louis - OPO Porto

STLOPO

Lambert-St Louis

Wed 10/28

4:40 pm-3:20 pm

1 stop17h 40m

Porto

Thu 4/22

4:35 pm-1:25 pm

1 stop26h 50m

$806

St. LouisPorto

STL Lambert-St Louis - OPO Porto

STLOPO

Lambert-St Louis

Wed 11/25

3:40 pm-11:45 am

1 stop14h 05m

Porto

Wed 12/2

6:00 am-1:45 pm

1 stop13h 45m

$819

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to Porto from

How to get the cheapest flight ticket from St. Louis to Porto

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the typical price of a round-trip flight between St. Louis and Porto?

Prices are currently low for flights on this route.

Typical prices usually range from $928 to $1,442.
The lowest price recently found on this route was $736.

What is the cheapest month to fly to Porto?

The month of December is, on average, the cheapest month to fly to Porto from St. Louis, with most prices found around $0. If you aren’t able to travel during the month of December, then book flights to Porto from St. Louis during January instead. Flights to Porto in January, while not as cheap as those in December, still average around $510.

Can stopping save me money on St. Louis to Porto flights?

You could potentially save up to 15% on your flight if you consider stops on a St. Louis to Porto flight.

When to book flights from St. Louis to Porto

Are you open to changing your travel dates? Check out the ideal times to fly from St. Louis to Porto according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap St. Louis to Porto (STL to OPO) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from St. Louis to Porto

Fastest flight time

15h 21m

Direct flights

None
The fastest flight from St. Louis to Porto takes 15h 21m
There are no direct flights from St. Louis to Porto. There are no popular flight routes from St. Louis to Porto.
Search flight deals

Frequently asked questions about flying from St. Louis to Porto

  • How far is Lambert-St Louis to Porto by plane?

    There are 4156.0 mi between Lambert-St Louis and Porto. A reasonable flight in good conditions will take 15h 21m.

  • When did momondo last update prices for flights from Lambert-St Louis Airport to Porto Airport?

    Prices for flights from Lambert-St Louis Airport to Porto Airport are refreshed on a daily basis.

  • How many operators does momondo search for flights from Lambert-St Louis Airport to Porto Airport?

  • How old do you have to be to fly from Lambert-St Louis Airport to Porto Airport?

    The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Lambert-St Louis Airport to Porto Airport.

  • What documentation or ID do you need to fly to Porto Airport?

    The travel and health documents you'll need for your trip to Porto Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Porto Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

  • What is the most popular airline from St. Louis to Porto?

Best airlines flying from St. Louis to Porto

Compare and see reviews for airlines that fly from St. Louis to Porto with momondo
Airline
Rating
Free Cancellation
Price
LufthansaPriceFrom $493Free CancellationRating
6.8
8,177 reviews
Search Lufthansa flights
United AirlinesPriceFrom $588Free CancellationRating
7.4
10,086 reviews
Search United Airlines flights

Traveling to a place near Porto?

Book flights to Porto if you plan to visit one of these locations
Vila Nova de Gaia
Coimbra
Braga
Aveiro
Matosinhos
Pinhao
Esposende
Lamego
Chaves
Arcos de Valdevez
Guimarães
Viseu
Espinho
Ponte de Lima
Mesao Frio
Penafiel
Baiao

Why use momondo?

Why should I use momondo to find a flight deal from St. Louis to Porto?

Finding the right flight to Porto from St. Louis is quick and easy when you have a range of options in front of you, from reputable agents and recognisable airlines. Options that can then be filtered down to find the best fit. That is what momondo does. We make finding flights to Porto quick and easy, saving you time and money.

Can I find flights from St. Louis to Porto with flexible booking policies on momondo?

All flight searches from St. Louis to Porto on momondo can be filtered to show those which offer flexible booking policies.

How can momondo help me find flights from St. Louis to Porto?

momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from St. Louis to Porto.

I’m not ready to book a flight from St. Louis to Porto right now. Can momondo alert me if prices change?

Price alerts on flights to Porto from St. Louis are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.

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