$347 Find Cheap Flights from St. Louis to Portugal

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from St. Louis to Portugal departing on 10/19. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

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Cheap Flights from St. Louis to Portugal

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
Lisbon
Lisbon1 stop$837
Porto
Porto1 stop$829
Lajes
Lajes2 stops$1,804
Lisbon
Lisbon1 stop$837
Porto
Porto1 stop$829
Lajes
Lajes2 stops$1,804

Book Cheap St. Louis to Portugal Plane Tickets

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from St. Louis to Portugal that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from St. Louis to Portugal

Sun, Oct 4 - Wed, Oct 21
United Airlines Logo
7:30 am - 9:45 am
STL
-
OPO
20h 15m
1 stop
United Airlines Logo
12:45 pm - 9:24 pm
OPO
-
STL
38h 39m
2 stops
$829United Airlines
Sun, Oct 4 - Wed, Oct 21
United Airlines Logo
8:15 pm - 7:00 am
STL
-
OPO
28h 45m
2 stops
United Airlines Logo
12:45 pm - 9:24 pm
OPO
-
STL
38h 39m
2 stops
$832United Airlines
Sun, Oct 4 - Wed, Oct 21
United Airlines Logo
6:15 am - 9:45 am
STL
-
OPO
21h 30m
2 stops
United Airlines Logo
12:45 pm - 9:24 pm
OPO
-
STL
38h 39m
2 stops
$833United Airlines
Sun, Oct 4 - Wed, Oct 21
Delta Logo
4:13 pm - 10:25 am
STL
-
OPO
12h 12m
1 stop
Delta Logo
5:00 am - 5:06 pm
OPO
-
STL
18h 06m
2 stops
$841Delta
Sun, Oct 4 - Wed, Oct 21
Delta Logo
11:51 am - 10:25 am
STL
-
OPO
16h 34m
2 stops
Delta Logo
5:00 am - 5:06 pm
OPO
-
STL
18h 06m
2 stops
$846Delta
Wed, Oct 14 - Fri, Oct 23
Air Canada Logo
12:10 pm - 9:20 am
STL
-
LIS
15h 10m
1 stop
Air Canada Logo
11:25 am - 2:18 pm
LIS
-
STL
32h 53m
2 stops
$852Air Canada
Wed, Oct 14 - Fri, Oct 23
Air Canada Logo
9:23 am - 9:20 am
STL
-
LIS
17h 57m
2 stops
Air Canada Logo
11:25 am - 2:18 pm
LIS
-
STL
32h 53m
2 stops
$857Air Canada
Wed, Oct 14 - Fri, Oct 23
British Airways Logo
9:35 pm - 5:55 pm
STL
-
LIS
14h 20m
1 stop
British Airways Logo
11:05 am - 11:41 pm
LIS
-
STL
18h 36m
1 stop
$862British Airways
Sat, Jun 20 - Sat, Jun 27
Multiple Airlines Logo
2:15 pm - 8:40 pm
STL
-
TER
25h 25m
2 stops
Multiple Airlines Logo
9:35 am - 10:29 am
TER
-
STL
29h 54m
3 stops
$1,804Multiple Airlines
Sat, Jun 20 - Sat, Jun 27
Multiple Airlines Logo
7:22 am - 8:40 pm
STL
-
TER
32h 18m
3 stops
Multiple Airlines Logo
9:35 am - 10:29 am
TER
-
STL
29h 54m
3 stops
$1,864Multiple Airlines
Booking Insights

KAYAK's insights & trends for St. Louis to Portugal flights

Get data-powered insights and trends into flights from St. Louis to Portugal to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest month to fly from St. Louis to Portugal?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from St. Louis to Portugal, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from St. Louis to Portugal is March, when tickets cost $458 (return) on average. On the other hand, the most expensive months are June and July, when the average cost of round-trip tickets is $791 and $754 respectively.

How far in advance should I book a flight from St. Louis to Portugal?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from St. Louis to Portugal, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from St. Louis to Portugal, you should book around 1 week before departure. For the absolute cheapest price, our data suggests you should book 1 week before departure.

Good to know

Low seasonFebruary
Cheapest flight$347
Best time to beat the crowds with an average 39% drop in price.
Most popular time to fly with an average 17% increase in price.
Flight from St. Louis to Porto

FAQs - booking Portugal flights

  • How does KAYAK find such low prices on flights from St. Louis to Portugal?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from St. Louis to Portugal.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from St. Louis to Portugal?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from St. Louis to Portugal is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from St. Louis to Portugal?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly from St. Louis to Portugal with an airline and back with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from St. Louis to Portugal?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying from St. Louis to Portugal up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Reviews of the top 5 airlines serving from St. Louis to Portugal

 
Need help choosing which airline to fly with from St. Louis to Portugal? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.9
DeltaOverall score based on 8458 reviews
8.5Crew
7.8Entertainment
7.9Comfort
8.1Boarding
7.2Food
Airline reviews

Much better than Latam, the worse airline company ever. I hope I don't have the need to fly Latam ever in my life again.

10.0 ExcellentIrmara, May 2026
MCO - BOS
Read more Delta reviews

Much better than Latam, the worse airline company ever. I hope I don't have the need to fly Latam ever in my life again.

Seats in Delta Main are unbelievably close to the seat in front of. Hard to get a backpack under the seat.

The flight was operated by Latam. The aircraft had a technical issue and the flight was delayed for the next day. They grounded other passengers to get their airplane assigned to my flight. Most of he ground staff don't speak English (Orlando Airport), but were very polite.The crew on the other hand could speak English and Portuguese. On board service was good.

The agent at check in and at the gate were less than thrilled to be at work. I'm not a fan of Kayak's placement on the plane. I got put in the middle seat and none of my preferences were used.

In ATL they have two sets of departure screens. Follow what is on your airline's departure board - the ATL Airport Authority departure board had completely incorrect details about the gate assignment for my flight, which would have made me miss boarding.

Flight was delayed it was hot while sitting on the plane, one engine was working on the plane until they had to do some jimmy rigging down the runway in order for the other engine to charge up. It was ridiculous

The flight was very good and the staff was very friendly and helpful!

The only thing I would say is we tried to get on a standby earlier flight, but with our fair we couldn’t. That seems senseless to leave with open seats..

Very easy to use and convenient, you can perform any action within the same portal

In a world of delays, Delta was on time both ways! Boarding was fast and efficient. Staff was friendly. AND wifi worked.

Left an hour and a half after the listed time. Up side was it had TV screens on the seat.

No screens or meal options. Freezing cold. Dirty seats. Left late.

O’hsre taxi and deboarding took 40 minutes. Needed 20 minutes extra time between connecting flights to avoid running through terminal.

Cree was organized and pleasant. Plane had good seating but as it’s a shuttle toilets hadn’t been thoroughly cleaned (eg. bins too full)

I liked that my son and I were reseated next to each other (we had different bookings). I liked that it was a directg flight and mostly on time. I liked that you provided pillows and blankets. Flight attendants were generally courteous. The messaging through wifi did not work well. The food was not good. Seats are very narrow and I felt slightly claustraphobic in the window seat.

Overall a good experience, but no wifi available for free or for purchase and we got wet from condensation or other water source during descent.

Some crew were unfriendly or in some cases just straight up rude.

Booked through Kayak Business, had a seat in middle and towards back due to booking rate, not comfortable.

Was great in general, try to respect time and excuses when slight changes have been made, appreciated!

A long delay. Don't travel late in the day.

Terrible, horrible, disappointing- without telling us they changed planes and moved and separated our seats to opposite sides - said they changed seats putting us together - got to airport to find no, they did not - we sat opposing sides of plane - food overly salty to inedible, never saw stewardess but once - it was terrible

not sure why you ask about food, I n3ver get food on flights except maybe cookies or pretzels. wifi was slow and in and out most of the flight not good.

The crew was very attentive through out the flight. Seats were comfortable, nice flight bag with pillow and blanket. Food was okay, since it was a overnight flight seemed to go by fast.

The flight attendant on my side of business class seemed like a novice and did not provide good service. Otherwise the flight was good and the entertainment system was very good. No free WiFi.

Cancelled BOYH legs of our flight home 30 min before initial boarding

Cancelled the flight half hour before boarding. Then cancelled the connecting flight too.

Left early arrived early..right amount of talking from pilots..of course had to love the biscuit and water!

I would like a refund for the extra cost the seat I paid for. An oversized person sat next to me and I couldn’t fit on my seat and had to move to another seat.

Boarding gate at LAX was too crowded—two gates next to one another

The flight was delayed about an hour for a maintenance specialist to approve the maintenance repair

I was charge a baggage checking fee $68!! I volunteered to check my duffle bag which usually goes under my seat!

I did not like anything because the flight was cancelled yesterday and I did not get to arrive on time in Toronto as I was rebooked with another airline. This caused me to be really stressed out as I am an individual with back injury and to be forced to stay longer in an airport to accommodate a change of airline and the transfers associated with it Due to this I am probably not going to book through your website to eliminate this potentially chaos in the future

shittiest airline in the hemisphere. To improve - start thinking you're flying people, not cattle

Easy boarding, inflight refreshments came on time and comfortable seat

It was good that our flight left early. It was a nice smooth flight and landing.

All good……but luggage didn’t make it on the airplane. Had to wait 3 days. Was a bummer.

Small suitcase used for carryon the last time was refused by boarding crew this time. Appears to be at the discretion and mood of the person on the day. Flight was only half booked, there would have been no problem with space.

It was a problem because there was a delay where we sat before taking off from newark,then when landed in Toronto we sat on tarmac and they wouldn't let us out for a long period of time. When we finally were released to the airport in Toronto the attendant scanned our boarding pass that we were here for our connection to Brazil. We ran all the way to the gate and they said at the gate the door is shut so we can not let you on the plane. We explained that we were checked in by the attendant when we arrived at Toronto airport to go to Brazil and they should not have shut the door. We were ignored at the gate

Flight home was delayed multiple times, did not get home until 2am

the check-in lady at ORD was extremely rude and unprofessional. very disappointed as it was supposed to be a celebration for my wife's birthday and it really put a damper on things. if i wanted to be treated like trash, i would have flown Economy! (as opposed to business class)

Definitely get premium economy on a flight this long if you can. Your legs and while body will thank you.

Flight was delayed by several hours and then cancelled due to weather. But Staff was very helpful getting me on a different flight. United should offer food coupons and tooth brush and paste for stranded passengers

I upgraded to the business class cabin. It was the poorest business class I have ever experienced. No access to any business lounge in Tampa airport. Seats are not comfortable. I had a window seat and had to step/crawl over the next seat. Food was mediocre and service below average for business class. Bathroom location was ridiculous. No place to wait. I cannot believe I paid this kind of money and will never fly Lufthansa Discover again. They really should reimburse me somehow.

Boarding was disorganized. The door to one to the toilets wouldn’t lock. The plane was shockingly cramped, and clearly used for domestic flights due to the menus for items to sell domestic travelers. United should be ashamed of its small seats, tiny unclean toilets, and money grubbing stance toward services, compared to Lufthansa, Emirates, and most international carriers United is awful.

Was never allowed on and not refunded the full amount of the ticket plus charged a $300 processing fee.

Terrible. Lost our luggage for 4 days. Did not advise passengers there was a strike in Barcelona Airport and had zero personnel on hand at airport to advise passengers on where to go to file claims. We had to fend for ourselves. No assistance at all other than an online claims submission process that we had to find out about on our own.

Lufthansa cancelled our flight from Los Angeles to Naples Italy on March 10 for scheduled flight on March 12 Very stressful experience trying to arrange alternatives. Will never fly again with Lufthansa

Everything could have been better. What needed to be wrong with United went wrong

The staff was bit rude when I asked for an extra drink after one beer, asked for one wine glass.

Very good, i got two seats for myself, and was comfortable with the blanket i got

Everything you need to know for your flight from St. Louis to Portugal

Information on your arrival and departure airports