Latest deals
Insights
When to book
FAQs
Reviews
Price Alerts

Cheap flights from St. Louis to Porto from $345

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 7/17. 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

Discover deals from 900+ travel sites with momondo.

Save money when you book flights with momondo

Big names and deals

Big names and deals

Search 100s of travel sites to compare prices.

Filter for what you want

Filter for what you want

Free Wi-Fi? Stopover? Instantly customize your results.

Trusted and free

Trusted and free

We’re completely free to use - no hidden charges or fees.

Price Alerts

Price Alerts

Not ready to book? to track prices.
Search flight deals

Find the cheapest flights from St. Louis to Porto

Cheap round-trip flights

Enter your travel dates to find the best prices.
American Airlines Logo
12:25 pm - 11:45 am
STL
-
OPO
17h 20m
2 stops
American Airlines Logo
8:20 am - 7:33 pm
OPO
-
STL
17h 13m
2 stops
$500American Airlines
Wed, Apr 15 - Wed, Apr 22
United Airlines Logo
7:45 am - 11:15 am
STL
-
OPO
21h 30m
2 stops
United Airlines Logo
6:00 am - 9:47 pm
OPO
-
STL
21h 47m
2 stops
$508United Airlines
Sun, Apr 19 - Tue, Apr 28
United Airlines Logo
3:30 pm - 11:15 am
STL
-
OPO
13h 45m
1 stop
United Airlines Logo
6:00 am - 9:47 pm
OPO
-
STL
21h 47m
2 stops
$599United Airlines
Sun, Apr 19 - Tue, Apr 28
KLM Logo
12:04 pm - 10:30 am
STL
-
OPO
17h 26m
2 stops
KLM Logo
5:00 am - 11:58 pm
OPO
-
STL
23h 58m
2 stops
$600KLM
Wed, Mar 18 - Wed, Mar 25
Lufthansa Logo
3:30 pm - 11:15 am
STL
-
OPO
13h 45m
1 stop
Lufthansa Logo
4:35 pm - 1:25 pm
OPO
-
STL
26h 50m
1 stop
$608Lufthansa
Sun, Apr 19 - Tue, Apr 28
Multiple Airlines Logo
4:05 pm - 2:45 pm
STL
-
OPO
17h 40m
2 stops
Multiple Airlines Logo
4:35 pm - 1:25 pm
OPO
-
STL
26h 50m
1 stop
$657Multiple Airlines
Tue, Mar 24 - Tue, Mar 31
United Airlines Logo
10:00 am - 9:30 am
STL
-
OPO
18h 30m
2 stops
United Airlines Logo
12:05 pm - 8:54 pm
OPO
-
STL
38h 49m
2 stops
$658United Airlines
Tue, Mar 24 - Tue, Mar 31
Lufthansa Logo
11:28 am - 2:45 pm
STL
-
OPO
22h 17m
2 stops
Lufthansa Logo
4:35 pm - 1:25 pm
OPO
-
STL
26h 50m
1 stop
$663Lufthansa
Tue, Mar 24 - Tue, Mar 31
United Airlines Logo
12:15 pm - 9:30 am
STL
-
OPO
15h 15m
2 stops
United Airlines Logo
6:00 am - 1:55 pm
OPO
-
STL
13h 55m
1 stop
$678United Airlines
Wed, Feb 25 - Sun, Mar 1
United Airlines Logo
7:40 am - 9:30 am
STL
-
OPO
20h 50m
2 stops
United Airlines Logo
6:00 am - 9:08 pm
OPO
-
STL
21h 08m
2 stops
$683United Airlines
Tue, Mar 24 - Tue, Mar 31

Delta flights from St. Louis to Porto

Our best Delta deals on St. Louis to Porto flight tickets
Delta
Apr 7
STL6:32 amLambert-St Louis
22h 23m
2 stops
OPO10:55 amPorto
Apr 13
OPO4:20 pmPorto
30h 30m
2 stops
STL4:50 pmLambert-St Louis
$694
Delta
Apr 6
STL6:32 amLambert-St Louis
26h 53m
2 stops
OPO3:25 pmPorto
Apr 13
OPO4:20 pmPorto
30h 30m
2 stops
STL4:50 pmLambert-St Louis
$736
Delta
Apr 5
STL6:32 amLambert-St Louis
22h 08m
2 stops
OPO10:40 amPorto
Apr 13
OPO4:20 pmPorto
30h 30m
2 stops
STL4:50 pmLambert-St Louis
$741

Air France flights from St. Louis to Porto

Our best Air France deals on St. Louis to Porto flight tickets
Air France
May 25
STL4:26 pmLambert-St Louis
16h 59m
2 stops
OPO3:25 pmPorto
Jun 4
OPO5:55 amPorto
17h 21m
2 stops
STL5:16 pmLambert-St Louis
$907
Air France
May 25
STL4:26 pmLambert-St Louis
16h 59m
2 stops
OPO3:25 pmPorto
Jun 4
OPO5:55 amPorto
17h 10m
2 stops
STL5:05 pmLambert-St Louis
$937

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 February 9, 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

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Wed 4/15

12:25 pm-11:45 am

2 stops17h 20m

Porto

Wed 4/22

8:20 am-7:33 pm

2 stops17h 13m

$500

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Sun 4/19

7:45 am-11:15 am

2 stops21h 30m

Porto

Tue 4/28

6:00 am-9:47 pm

2 stops21h 47m

$508

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Sun 4/19

3:30 pm-11:15 am

1 stop13h 45m

Porto

Tue 4/28

6:00 am-9:47 pm

2 stops21h 47m

$599

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Wed 3/18

12:04 pm-10:30 am

2 stops17h 26m

Porto

Wed 3/25

5:00 am-11:58 pm

2 stops23h 58m

$600

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Sun 4/19

3:30 pm-11:15 am

1 stop13h 45m

Porto

Tue 4/28

4:35 pm-1:25 pm

1 stop26h 50m

$608

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Tue 3/24

4:05 pm-2:45 pm

2 stops17h 40m

Porto

Tue 3/31

4:35 pm-1:25 pm

1 stop26h 50m

$657

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Tue 3/24

10:00 am-9:30 am

2 stops18h 30m

Porto

Tue 3/31

12:05 pm-8:54 pm

2 stops38h 49m

$658

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Tue 3/24

11:28 am-2:45 pm

2 stops22h 17m

Porto

Tue 3/31

4:35 pm-1:25 pm

1 stop26h 50m

$663

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Wed 2/25

12:15 pm-9:30 am

2 stops15h 15m

Porto

Sun 3/1

6:00 am-1:55 pm

1 stop13h 55m

$678

St. LouisPorto

STL - OPO

STLOPO

Lambert-St Louis

Tue 3/24

7:40 am-9:30 am

2 stops20h 50m

Porto

Tue 3/31

6:00 am-9:08 pm

2 stops21h 08m

$683

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
1
2

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

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

You could potentially save up to 19% 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

16h 59m

Direct flights

None
The fastest flight from St. Louis to Porto takes 16h 59m
There are no direct flights from St. Louis to Porto. There are no popular flight routes from St. Louis to Porto.
Search flight deals

  • 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 16h 59m.

  • 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
American AirlinesPriceFrom $460Free CancellationRating
7.2
11,255 reviews
Search American Airlines flights
LufthansaPriceFrom $520Free CancellationRating
6.8
7,775 reviews
Search Lufthansa flights
DeltaPriceFrom $550Free CancellationRating
7.9
8,174 reviews
Search Delta flights
United AirlinesPriceFrom $760Free CancellationRating
7.4
9,259 reviews
Search United Airlines flights
Air CanadaPriceFrom $787Free CancellationRating
7.1
10,698 reviews
Search Air Canada 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
Esposende
Lamego
Guimarães
Espinho
Chaves
Pinhao
Arcos de Valdevez
Viseu
Ponte de Lima
Curia
Penafiel
Mesao Frio
Mira
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.

An easier way to manage your Porto trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.
Start using Trips
Find my bookings

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.
1 adult
Wed 3/11
Wed 3/18
By creating a price alert you accept our terms of use and privacy policy.

Find better results for your trip to Portugal