$394 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 9/28. 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$815
Porto
Porto1 stop$841
Lajes
Lajes2 stops$2,538
Lisbon
Lisbon1 stop$815
Porto
Porto1 stop$841
Lajes
Lajes2 stops$2,538

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

Wed, Apr 22 - Sun, Apr 26
Delta Logo
6:25 am - 8:00 am
STL
-
LIS
19h 35m
1 stop
Delta Logo
5:00 am - 11:13 pm
LIS
-
STL
24h 13m
2 stops
$815Delta
Mon, Apr 20 - Mon, Apr 27
Delta Logo
11:42 am - 10:45 am
STL
-
LIS
17h 03m
2 stops
Delta Logo
5:00 am - 11:36 pm
LIS
-
STL
24h 36m
2 stops
$820Delta
Tue, Apr 21 - Mon, Apr 27
Delta Logo
5:27 pm - 8:00 am
STL
-
LIS
32h 33m
1 stop
Delta Logo
5:00 am - 11:13 pm
LIS
-
STL
24h 13m
2 stops
$821Delta
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
Iberia Logo
8:07 pm - 4:00 pm
STL
-
OPO
13h 53m
2 stops
Iberia Logo
8:20 am - 8:08 pm
OPO
-
STL
17h 48m
2 stops
$852Iberia
Sun, Oct 4 - Fri, Oct 16
United Airlines Logo
8:55 am - 11:00 am
STL
-
LIS
20h 05m
1 stop
United Airlines Logo
11:25 am - 4:26 pm
LIS
-
STL
35h 01m
2 stops
$856United Airlines
Sun, Oct 4 - Fri, Oct 16
United Airlines Logo
6:49 pm - 9:20 am
STL
-
LIS
32h 31m
2 stops
United Airlines Logo
11:25 am - 4:26 pm
LIS
-
STL
35h 01m
2 stops
$861United Airlines
Sun, Oct 4 - Wed, Oct 21
American Airlines Logo
2:45 pm - 4:00 pm
STL
-
OPO
19h 15m
2 stops
American Airlines Logo
8:20 am - 6:04 pm
OPO
-
STL
15h 44m
2 stops
$882American Airlines
Mon, Sep 28 - Mon, Oct 19
Iberia Logo
8:07 pm - 8:00 pm
STL
-
OPO
17h 53m
2 stops
Iberia Logo
8:20 am - 8:08 pm
OPO
-
STL
17h 48m
2 stops
$912Iberia
Mon, Sep 28 - Mon, Oct 19
KLM Logo
4:13 pm - 10:30 am
STL
-
OPO
12h 17m
1 stop
KLM Logo
12:15 pm - 11:39 pm
OPO
-
STL
17h 24m
2 stops
$913KLM
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 April, when tickets cost $587 (return) on average. On the other hand, the most expensive months are December and June, when the average cost of round-trip tickets is $2,683 and $1,284 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$394
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 8406 reviews
7.8Entertainment
7.9Comfort
8.5Crew
8.1Boarding
7.2Food
Airline reviews

The flight was smooth, the crew was great but the plane was quite old

8.0 ExcellentDimitrina, Apr 2026
BOS - DCA
Read more Delta reviews

The flight was smooth, the crew was great but the plane was quite old

Everything was great until I lost my water bottle and they can’t seem to locate it. I know I left it on the plane though.

WiFi didn’t work most of the time. The usb chargers would work only occasionally for 5 mins and wouldn’t charge after that. Had to keep trying repeatedly at each of the seats in the row.

The crew bent over backwards to thank us for flying and make us comfortable. The food service was quick and efficient. The Captain communicated and said goodbye and thank you as we departed. They really stood out!

Okay considering we had weather delays which the Pilot notified us of immediately!

Generally on time departures and arrivals, clean planes, sky miles membership provides great benefits (complimentary upgrades, etc).

Flight from Fort Wayne to Atlanta was the smallest in terms of cabin space that I've ever seen. A carry on I've used for 20 years BARELY fit in overhead compartment. I'm 5'10" and felt very cramped. Not the best experience.

I am writing to express my dissatisfaction with the poor service and unprofessional staff we encountered when traveling with an infant. Our flight was delayed, and the gate staff failed to manage the boarding process appropriately. Due to incorrect, unavailable, or missing 'pink tag' stroller and car seat check-in procedures at the gate, we were forced to board last. Furthermore, the gate staff was rude and dismissive, causing significant distress to our infant. To make matters worse, one of our checked items—an infant sleeper/lounger—was returned to us broken. Given the unsafe handling of essential equipment and unprofessional treatment, I expect a prompt resolution regarding compensation for the damaged items.

We departed and landed early which was a nice surprise. The boarding process was slow.

N Everything was perfect from boarding to assistance to baggage in Tampa

Great flight. Got to watch a movie. Smooth flight and early arrival at ORD.

This was the first flight in the morning. We boarded fine. The cabin door was closed and we were ready to go. We were notified by the Captain that ATC issued and ground stop for 40 minutes. So, without even pushing back from the gate, we were already 40 minutes late. We actually were released to push-back and taxi at 30 minutes. But, some passengers had tight connections and were not going to make their connections. Some passengers asked about the delay and the effect on the connections and were told by the cabin attendant that all flights will be delayed and so they should be OK. However, that was not true. My connecting flight was on time and I arrived at IAH with 21 minutes to make my connection. I did and I'm happy about that, but the flight crew should not have given assurances to the passengers who might have missed their connections.

Poor communication, flight was delayed for preventable reasons. I missed my connection.

It was better than excellent. The staff in Mason City were great. The young woman that pushed my wheelchair did more than could be expected of her. She came from India 17 years ago. I don't remember her name.

After arriving in Chicago, we were taxiing for 1.5 hours with infrequent and untruthful updates about the amount of time it would take to arrive at the gate. Minimally, the team could have provided timing expectations that were more truthful, especially one their original expectations were not met.

All good flight was 35 minutes early when arriving in Edinburgh

Flights were on time actually early service was good and crew cheerful

Every staff member was professional, friendly and courteous. The pizza twist was ok. It was warm but too much dough.

The boarding timing needs to be improved. The flight was delayed again because it took way too long to board. I was already exhausted from sleeping at the airport and spending all day there due to delay from my previous flight that connected in Chicago.

I had a terrible experience. My flight got delayed from Atlanta to Chicago on Monday April 6, 2026, and that led to me missing my next flight to Brussels. United Airlines didn’t provide me with any accommodation for shelter. I had to sleep at the airport in Chicago. The next flight I was put on didn’t leave until the evening hours of Tuesday 4/7/2026.

THe flight was an hour late. You got us on the plan and we sat on the ground for 45 minutes with no information from the pilot whatsoever. Worst flight this year.

Boarding was quick and efficient. We arrived at our destination early.

I'm not sure American is capable of on-time arrivals and departures. When you land at ORD, you almost always get held on the tarmac because your gate is still occupied. I may have missed my connection, but that ended up up being significantly delayed as well. Once again, I finally got home well after midnight.

Same plane as RDU to LGA — internet not working. Pilot issue of some sort at end of prior flight - I was on same plane for my connection. Late/delayed —

Good flight, seated and had a water within 5 minutes. Crew was hospitable.

Message about flight cancelation was received late due to being in the air. No explanation, just canceled and booked on morning flight. We had to stay in the airport overnight because there was no transportation offered to get to the hotel that AA had available. Actual inflight was fine.

I didn't go from Reno to Phoenix I ended up going from Reno to Dallas to Tucson because my flight rebooked because my Amtrak was late I tried notifying you guys I also don't know what you ask me about my flight because you guys didn't book my flight

Delays experienced in boarding/take off due to incoming plane delayed. However, the boarding time/depart time in the app was significantly delayed in providing these updates. Usually not updated until an hour after we should have already boarded. Poorly managed.

Bag drop was very disorganized in Miami. All main cabin passengers were shunted to just a few lanes and they had an equal number of lanes for first class passengers but there was nobody on those lines. They did nothing to bring the main cab and passengers over to the open lines and they just had employees standing there and doing nothing

there are no options s for snack besides cookies would ve nice to have a salty option n

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)

My original flight was cancelled and then rebooked four hours later on a recovery flight, but I was checked in as stanby and had no seats so as a family of four we were concerned about not being seated altogether. Our flight then got delayed by another 1.5 hours and when seats were assigned at the gate, three of the four of us were together and we could get my wife closer, they offered no assistance.

Rude flight attendants with poor service. Worst first class experience I’ve ever had.

I bought a ticket from Kayak. When I got to the airport, the was no ticket. I had to pay 5X to get to my destination. No response received from Kayak. I will NEVER use them again.

My wallet was stolen while I was sleeping on the plane.

Good boarding but extremely cold temperature in both flights (60 F!).

The whole plane smelled and felt old. The seats were very uncomfortable. Multiple delays. Extra fees.

Very rude gate attendants in San Francisco who didn’t let me bring my little carry on (smaller than usual size) and after boarding I realized that there still were a lot of overhead compartment space (like a full section available in some spots). That made me lose 30 minutes at my destination at 1am and it could have broken something fragile that I had in it

The most uncomfortable flight I’ve ever been on. I’m only 5,4” and barely had enough room to exist, couldn’t even fully relax my shoulders. Not sure why they bother with snacks. Half a coke and a single cookie?? Wow. Purchasable food looked gross too. Remember when airlines used to treat you like a human being?

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

I hated the FRA Airport. Confusing signage, including the path to Immigration and Security It seems that the airport grew haphazardly over the years. I have been through multiple WW Hubs with much better experiences.

Economy Priority seats are extremely uncomfortable. There is no way to escape the boxed in feeling, particularely because the distance between to rows are too short, the hard edge of the front row is keeping legs confined. There is no elevated place to put your feet. I am of average, European size.

Terrible. Both flights were significantly delayed, no luggage, made me check my small bag when many, many others had much larger carry-ons, not even a bottle of water . . . I will not fly Discover Airlines again.

I was deceived on the Kayak site expecting a ticket, but instead finding a "standby" reservation. When I tried to change the ticket, I paid almost twice the price of the original ticket. Then, the airline refused to give me the reserved seat I had chosen and paid for. I think I deserve a refund for this leg of my trip because I was doubly charged and did not receive what I had paid for. I put in a complaint with Lufthansa because the ticket was sold originally sold as a flight they listed. Someone here needs to take responsibility.

Excellent service; they helped me reschedule so I can fly in an earlier flight

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

Information on your arrival and departure airports