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Cheap flights from Porto to St. Louis from $454

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Porto to St. Louis departing on 9/11. 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

Find the cheapest flights from Porto to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
American Airlines Logo
8:20 am - 7:27 pm
OPO
-
STL
17h 07m
2 stops
American Airlines Logo
1:49 pm - 11:45 am
STL
-
OPO
15h 56m
2 stops
$843American Airlines
Wed, Sep 2 - Thu, Sep 10
American Airlines Logo
12:25 pm - 2:24 pm
OPO
-
STL
31h 59m
2 stops
American Airlines Logo
6:53 pm - 4:00 pm
STL
-
OPO
39h 07m
2 stops
$845American Airlines
Wed, Dec 2 - Sat, Dec 5
Multiple Airlines Logo
11:45 am - 11:21 pm
OPO
-
STL
17h 36m
2 stops
Multiple Airlines Logo
3:54 pm - 3:25 pm
STL
-
OPO
17h 31m
2 stops
$849Multiple Airlines
Wed, Sep 2 - Fri, Sep 11
American Airlines Logo
12:25 pm - 12:15 pm
OPO
-
STL
29h 50m
2 stops
American Airlines Logo
8:54 am - 4:00 pm
STL
-
OPO
25h 06m
2 stops
$851American Airlines
Fri, Sep 4 - Sat, Sep 12
KLM Logo
5:00 am - 7:58 pm
OPO
-
STL
20h 58m
2 stops
KLM Logo
5:45 pm - 3:30 pm
STL
-
OPO
15h 45m
2 stops
$854KLM
Thu, Sep 10 - Fri, Oct 16
Air France Logo
5:55 am - 4:17 pm
OPO
-
STL
16h 22m
2 stops
Air France Logo
3:54 pm - 3:25 pm
STL
-
OPO
17h 31m
2 stops
$855Air France
Fri, Sep 4 - Fri, Sep 11
Delta Logo
6:10 am - 4:47 pm
OPO
-
STL
16h 37m
2 stops
Delta Logo
7:20 am - 10:30 am
STL
-
OPO
21h 10m
2 stops
$859Delta
Sat, Sep 12 - Fri, Oct 16
British Airways Logo
7:55 pm - 4:48 pm
OPO
-
STL
26h 53m
2 stops
British Airways Logo
9:35 pm - 7:05 pm
STL
-
OPO
15h 30m
1 stop
$890British Airways
Thu, Sep 10 - Wed, Oct 14
Multiple Airlines Logo
11:35 am - 11:42 pm
OPO
-
STL
18h 07m
2 stops
Multiple Airlines Logo
11:51 am - 8:30 am
STL
-
OPO
14h 39m
2 stops
$902Multiple Airlines
Thu, Sep 10 - Thu, Oct 15
Multiple Airlines Logo
6:10 am - 4:32 pm
OPO
-
STL
16h 22m
2 stops
Multiple Airlines Logo
5:45 pm - 3:25 pm
STL
-
OPO
15h 40m
2 stops
$909Multiple Airlines
Sat, Sep 12 - Wed, Oct 14

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Air France flights from Porto to St. Louis

Our best Air France deals on Porto to St. Louis flight tickets
Air France
Sep 4
OPO5:55 amPorto
16h 22m
2 stops
STL4:17 pmLambert-St Louis
Sep 11
STL3:54 pmLambert-St Louis
17h 31m
2 stops
OPO3:25 pmPorto
$855
Air France
Sep 12
OPO6:10 amPorto
19h 48m
2 stops
STL7:58 pmLambert-St Louis
Oct 15
STL5:45 pmLambert-St Louis
15h 40m
2 stops
OPO3:25 pmPorto
$961
Air France
Jun 19
OPO5:55 amPorto
16h 51m
2 stops
STL4:46 pmLambert-St Louis
Jun 21
STL3:57 pmLambert-St Louis
17h 28m
2 stops
OPO3:25 pmPorto
$1,002

United Airlines flights from Porto to St. Louis

Our best United Airlines deals on Porto to St. Louis flight tickets
United Airlines
Sep 2
OPO6:00 amPorto
23h 38m
2 stops
STL11:38 pmLambert-St Louis
Sep 10
STL12:28 pmLambert-St Louis
12h 27m
1 stop
OPO6:55 amPorto
$948
United Airlines
Sep 1
OPO12:05 pmPorto
31h 20m
1 stop
STL1:25 pmLambert-St Louis
Sep 12
STL8:50 amLambert-St Louis
16h 05m
2 stops
OPO6:55 amPorto
$963
United Airlines
Sep 2
OPO11:20 amPorto
13h 22m
1 stop
STL6:42 pmLambert-St Louis
Sep 9
STL12:28 pmLambert-St Louis
15h 17m
1 stop
OPO9:45 amPorto
$969

momondo 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, momondo users made 832,500 searches. Data last updated June 18, 2026.
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

Cheapest round-trip

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Wed 9/2

8:20 am-7:27 pm

2 stops17h 07m

Lambert-St Louis

Thu 9/10

1:49 pm-11:45 am

2 stops15h 56m

$843

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Wed 12/2

12:25 pm-2:24 pm

2 stops31h 59m

Lambert-St Louis

Sat 12/5

6:53 pm-4:00 pm

2 stops39h 07m

$845

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Wed 9/2

11:45 am-11:21 pm

2 stops17h 36m

Lambert-St Louis

Fri 9/11

3:54 pm-3:25 pm

2 stops17h 31m

$849

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Fri 9/4

12:25 pm-12:15 pm

2 stops29h 50m

Lambert-St Louis

Sat 9/12

8:54 am-4:00 pm

2 stops25h 06m

$851

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Thu 9/10

5:00 am-7:58 pm

2 stops20h 58m

Lambert-St Louis

Fri 10/16

5:45 pm-3:30 pm

2 stops15h 45m

$854

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Fri 9/4

5:55 am-4:17 pm

2 stops16h 22m

Lambert-St Louis

Fri 9/11

3:54 pm-3:25 pm

2 stops17h 31m

$855

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Sat 9/12

6:10 am-4:47 pm

2 stops16h 37m

Lambert-St Louis

Fri 10/16

7:20 am-10:30 am

2 stops21h 10m

$859

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Thu 9/10

7:55 pm-4:48 pm

2 stops26h 53m

Lambert-St Louis

Wed 10/14

9:35 pm-7:05 pm

1 stop15h 30m

$890

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Thu 9/10

11:35 am-11:42 pm

2 stops18h 07m

Lambert-St Louis

Thu 10/15

11:51 am-8:30 am

2 stops14h 39m

$902
Quickest round-trip

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Sat 9/12

6:10 am-4:32 pm

2 stops16h 22m

Lambert-St Louis

Wed 10/14

5:45 pm-3:25 pm

2 stops15h 40m

$909

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 St. Louis from

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

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

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

You could potentially save up to 40% on your flight if you consider stops on a Porto to St. Louis flight.

When to book flights from Porto to St. Louis

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

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

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

Fastest flight time

17h 11m

Direct flights

None
The fastest flight from Porto to St. Louis takes 17h 11m
There are no direct flights from Porto to St. Louis. There are no popular flight routes from Porto to St. Louis.
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Frequently asked questions about flying from Porto to St. Louis

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

    There are 4156.0 mi between Porto and Lambert-St Louis. A reasonable flight in good conditions will take 17h 11m.

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

    Prices for flights from Porto Airport to Lambert-St Louis Airport refresh daily.

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

  • What documentation or ID do you need to fly to Lambert-St Louis Airport?

    The necessary travel and health documents for your Lambert-St Louis Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
St. Charles
Chesterfield
Fairview Heights
Hermann
Maryland Heights
Florissant
O'Fallon
St. Peters
Collinsville
Alton
Wentzville
Clayton
Fenton
Farmington
Festus
Eureka
Litchfield
Edwardsville
Grafton
Shrewsbury

Why use momondo?

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

It is quick and easy to find Porto to St. Louis flights on momondo. We search and return numerous flight options from various airlines and agents. You can then use our filters to narrow your search until you have found the most convenient flight to St. Louis that suits you.

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

Yes. All flights to St. Louis from Porto on momondo can be compared and filtered by various policies on offer, including flexible booking.

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

momondo helps you find the best flight between Porto and St. Louis by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.

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

Of course. momondo tracks the price of Porto to St. Louis flights. All you need is a valid email address and we will do the rest; it is that quick and easy.

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