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Cheap flights from Porto to St. Louis from $559

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 9/24. 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
0 bags

Find the cheapest flights from Porto to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
Lufthansa Logo
12:05 pm - 11:00 pm
OPO
-
STL
16h 55m
2 stops
Lufthansa Logo
12:30 pm - 9:45 am
STL
-
OPO
15h 15m
1 stop
$958Lufthansa
Tue, Sep 1 - Mon, Sep 7
United Airlines Logo
6:00 am - 8:37 am
OPO
-
STL
32h 37m
2 stops
United Airlines Logo
10:23 am - 9:45 am
STL
-
OPO
17h 22m
2 stops
$961United Airlines
Fri, Oct 16 - Mon, Oct 19
Lufthansa Logo
4:35 pm - 1:25 pm
OPO
-
STL
26h 50m
1 stop
Lufthansa Logo
3:30 pm - 10:50 pm
STL
-
OPO
25h 20m
1 stop
$963Lufthansa
Tue, Sep 1 - Mon, Sep 7
Delta Logo
5:00 am - 8:39 pm
OPO
-
STL
21h 39m
2 stops
Delta Logo
7:08 am - 10:30 am
STL
-
OPO
21h 22m
2 stops
$967Delta
Mon, Jun 15 - Mon, Jun 22
Lufthansa Logo
4:35 pm - 1:25 pm
OPO
-
STL
26h 50m
1 stop
Lufthansa Logo
12:30 pm - 6:55 am
STL
-
OPO
12h 25m
1 stop
$973Lufthansa
Tue, Sep 1 - Mon, Sep 7
United Airlines Logo
6:00 am - 11:35 pm
OPO
-
STL
23h 35m
2 stops
United Airlines Logo
6:00 am - 9:45 am
STL
-
OPO
21h 45m
1 stop
$976United Airlines
Mon, Jun 15 - Mon, Jun 22
American Airlines Logo
8:20 am - 11:25 pm
OPO
-
STL
21h 05m
2 stops
American Airlines Logo
9:35 am - 11:45 am
STL
-
OPO
20h 10m
2 stops
$978American Airlines
Fri, Oct 16 - Wed, Oct 21
Air France Logo
12:45 pm - 5:06 pm
OPO
-
STL
34h 21m
1 stop
Air France Logo
5:45 pm - 3:25 pm
STL
-
OPO
15h 40m
2 stops
$981Air France
Fri, Oct 16 - Tue, Oct 20
United Airlines Logo
12:35 pm - 12:20 pm
OPO
-
STL
29h 45m
2 stops
United Airlines Logo
4:55 pm - 9:45 am
STL
-
OPO
10h 50m
1 stop
$985United Airlines
Fri, Oct 16 - Wed, Oct 21
Lufthansa Logo
12:05 pm - 11:00 pm
OPO
-
STL
16h 55m
2 stops
Lufthansa Logo
1:18 pm - 3:45 pm
STL
-
OPO
44h 27m
2 stops
$992Lufthansa
Tue, Sep 1 - Mon, Sep 7

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United Airlines flights from Porto to St. Louis

Our best United Airlines deals on Porto to St. Louis flight tickets
United Airlines
Oct 16
OPO6:00 amPorto
32h 37m
2 stops
STL8:37 amLambert-St Louis
Oct 19
STL10:23 amLambert-St Louis
17h 22m
2 stops
OPO9:45 amPorto
$961
United Airlines
Jun 15
OPO6:00 amPorto
23h 35m
2 stops
STL11:35 pmLambert-St Louis
Jun 22
STL6:00 amLambert-St Louis
21h 45m
1 stop
OPO9:45 amPorto
$976
United Airlines
Oct 16
OPO12:35 pmPorto
29h 45m
2 stops
STL12:20 pmLambert-St Louis
Oct 21
STL4:55 pmLambert-St Louis
10h 50m
1 stop
OPO9:45 amPorto
$985

American Airlines flights from Porto to St. Louis

Our best American Airlines deals on Porto to St. Louis flight tickets
American Airlines
Oct 16
OPO8:20 amPorto
21h 05m
2 stops
STL11:25 pmLambert-St Louis
Oct 21
STL9:35 amLambert-St Louis
20h 10m
2 stops
OPO11:45 amPorto
$978
American Airlines
May 14
OPO8:20 amPorto
19h 47m
2 stops
STL10:07 pmLambert-St Louis
May 18
STL9:10 amLambert-St Louis
16h 30m
2 stops
OPO7:40 amPorto
$1,145

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 May 4, 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
Quickest round-trip

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Tue 9/1

12:05 pm-11:00 pm

2 stops16h 55m

Lambert-St Louis

Mon 9/7

12:30 pm-9:45 am

1 stop15h 15m

$958

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Fri 10/16

6:00 am-8:37 am

2 stops32h 37m

Lambert-St Louis

Mon 10/19

10:23 am-9:45 am

2 stops17h 22m

$961

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Tue 9/1

4:35 pm-1:25 pm

1 stop26h 50m

Lambert-St Louis

Mon 9/7

3:30 pm-10:50 pm

1 stop25h 20m

$963

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Mon 6/15

5:00 am-8:39 pm

2 stops21h 39m

Lambert-St Louis

Mon 6/22

7:08 am-10:30 am

2 stops21h 22m

$967

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Tue 9/1

4:35 pm-1:25 pm

1 stop26h 50m

Lambert-St Louis

Mon 9/7

12:30 pm-6:55 am

1 stop12h 25m

$973

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Mon 6/15

6:00 am-11:35 pm

2 stops23h 35m

Lambert-St Louis

Mon 6/22

6:00 am-9:45 am

1 stop21h 45m

$976

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Fri 10/16

8:20 am-11:25 pm

2 stops21h 05m

Lambert-St Louis

Wed 10/21

9:35 am-11:45 am

2 stops20h 10m

$978

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Fri 10/16

12:45 pm-5:06 pm

1 stop34h 21m

Lambert-St Louis

Tue 10/20

5:45 pm-3:25 pm

2 stops15h 40m

$981

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Fri 10/16

12:35 pm-12:20 pm

2 stops29h 45m

Lambert-St Louis

Wed 10/21

4:55 pm-9:45 am

1 stop10h 50m

$985

PortoSt. Louis

OPO - STL

OPOSTL

Porto

Tue 9/1

12:05 pm-11:00 pm

2 stops16h 55m

Lambert-St Louis

Mon 9/7

1:18 pm-3:45 pm

2 stops44h 27m

$992

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 16 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 31% 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 48m

Direct flights

None
The fastest flight from Porto to St. Louis takes 17h 48m
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 48m.

  • 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
Hermann
Fairview Heights
Maryland Heights
O'Fallon
Florissant
St. Peters
Collinsville
Wentzville
Alton
Fenton
Farmington
Festus
Clayton
Eureka
Litchfield
Edwardsville
Shrewsbury
Grafton

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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