STL - SJU

$161 Find Cheap Flights from St. Louis to San Juan

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 San Juan departing on 8/17. 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

KAYAK searches hundreds of travel sites at once for deals on flights to San Juan Luis Munoz Marin Intl Airport

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to San Juan.
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to San Juan.
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Everything you should know

Cheapest round-trip
$336
Typical prices: $533-$286
Delta
Fri 8/21Tue 8/25
STL - SJU • 1 stop
Cheapest one-way
$161
Typical prices: $146-$206
Frontier
Mon 8/17
STL - SJU • 2 stops
Advice from real travelers
AI-powered summary based on content written by travel experts. AI can make mistakes.
Avoid peak hours at STL for shorter wait times.
For quick access to San Juan, taxis or Uber are best.
Expert advice
Expert advice
Expert advice
Expert advice
Nonstop flights
1 day a week
Sat
You can fly direct with Southwest. Average duration is 4h 25m
Direct flights
Direct flights
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Direct flights
Direct flights
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Top airlines
Cheapest • from $336 (round-trip)
Best reviews • 7.9 score
Airline reviews
Airline reviews
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Airline reviews
Airline reviews
+1
Top layover airports
Cheapest • Avg $269 (round-trip)
Shortest trip • 7h 18m (one-way)
Insights
Insights
Insights
Insights
Avoid delays
Most punctual • 67% on-time
Best time • Fewest delays
Insights
Insights
Insights
Insights
When to travel
Cheapest • 47% price drop
Most popular
Good to know
Good to know
+1
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Good to know
Good to know
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Start a new search
KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to San Juan!
Flight Deals
Booking Insights
Expert advice
Flight Deals

Cheap Flights from St. Louis to San Juan (STL-SJU)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from St. Louis to San Juan 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 San Juan

Fri, Aug 21 - Tue, Aug 25
Delta Logo
12:52 pm - 10:29 pm
STL
-
SJU
8h 37m
1 stop
Delta Logo
6:48 am - 2:33 pm
SJU
-
STL
8h 45m
1 stop
$336Delta
Wed, Sep 2 - Wed, Sep 9
American Airlines Logo
6:54 am - 6:24 pm
STL
-
SJU
10h 30m
2 stops
American Airlines Logo
6:30 am - 1:22 pm
SJU
-
STL
7h 52m
1 stop
$341American Airlines
Tue, Oct 27 - Tue, Nov 3
United Airlines Logo
11:45 am - 11:36 pm
STL
-
SJU
10h 51m
2 stops
United Airlines Logo
8:10 am - 2:18 pm
SJU
-
STL
8h 08m
1 stop
$355United Airlines
Tue, Jul 28 - Sun, Aug 2
Frontier Logo
6:33 pm - 12:41 am
STL
-
SJU
29h 08m
2 stops
Frontier Logo
5:15 pm - 8:57 am
SJU
-
STL
16h 42m
1 stop
$362Frontier
Tue, Sep 8 - Fri, Sep 11
United Airlines Logo
11:15 am - 8:38 pm
STL
-
SJU
8h 23m
1 stop
United Airlines Logo
1:00 am - 12:02 pm
SJU
-
STL
12h 02m
2 stops
$371United Airlines
Wed, Aug 5 - Tue, Aug 11
Southwest Logo
10:15 am - 9:05 pm
STL
-
SJU
9h 50m
2 stops
Southwest Logo
1:20 pm - 7:55 pm
SJU
-
STL
7h 35m
1 stop
$373Southwest
Mon, Aug 3 - Mon, Aug 10
Frontier Logo
4:52 pm - 12:41 am
STL
-
SJU
30h 49m
2 stops
Frontier Logo
6:31 pm - 11:59 pm
SJU
-
STL
30h 28m
1 stop
$375Frontier
Wed, Jul 8 - Wed, Jul 15
Frontier Logo
4:09 pm - 7:32 pm
STL
-
SJU
26h 23m
1 stop
Frontier Logo
8:37 pm - 11:59 pm
SJU
-
STL
28h 22m
1 stop
$376Frontier
Mon, Jul 27 - Sun, Aug 2
Frontier Logo
4:52 pm - 2:00 pm
STL
-
SJU
44h 08m
2 stops
Frontier Logo
5:15 pm - 8:57 am
SJU
-
STL
16h 42m
1 stop
$379Frontier
Mon, Aug 10 - Sun, Aug 16
Frontier Logo
4:52 pm - 12:07 am
STL
-
SJU
30h 15m
2 stops
Frontier Logo
5:15 pm - 8:57 am
SJU
-
STL
16h 42m
1 stop
$380Frontier
Booking Insights

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

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

How much is a round-trip flight from St. Louis to San Juan Luis Munoz Marin Intl Airport?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from St. Louis to San Juan Luis Munoz Marin Intl Airport departing in August.

What is the cheapest month to fly from St. Louis to San Juan Luis Munoz Marin Intl Airport?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from St. Louis to San Juan Luis Munoz Marin Intl Airport, 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 San Juan Luis Munoz Marin Intl Airport is September, where tickets cost $224 (return) on average. On the other hand, the most expensive months are December and July, where the average cost of round-trip tickets is $615 and $530 respectively.

How far in advance should I book a flight from St. Louis to San Juan Luis Munoz Marin Intl Airport?

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 San Juan Luis Munoz Marin Intl Airport, 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 San Juan Luis Munoz Marin Intl Airport, you should book around 1 week before departure. For the absolute cheapest price, our data suggests you should book 14 weeks before departure.

Expert advice

Expert advice for your flight from St. Louis to San Juan

 
AI-powered summary based on content written by travel experts. AI can make mistakes.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Our travel experts
Yulia Denisyuk

Yulia Denisyuk

Expert on STL

Yulia is a freelance journalist who’s dispatched from 90+ countries. Her work focuses on cultures, adventure trips and air travel, appearing in NatGeo, NYT, CNTraveler, and more. For past assignments, she’s stayed with nomads in Mongolia and learned the art of Imigongo in Rwanda. She’s based in Chicago; in winter she often questions that decision.

Gabriel Leigh

Gabriel Leigh

Expert on SJU

Gabriel is a writer and video creator. As senior content producer for Flightradar24 and Monocle’s transport correspondent, he keeps a close eye on aviation in particular. He has also written travel articles for the likes of The New York Times. Born in New York but raised around the world, he now lives in Sweden. He’s been to 75 countries, flying 2.3 million miles on 113 airlines and through 234 airports in the process.

Good to know

Low seasonSeptember
Cheapest flight$161
Best time to beat the crowds with an average 47% drop in price.
Most popular time to fly and prices are also 4% lower on average.
Flight from St. Louis to San Juan

When to book flights from St. Louis to San Juan

Are your dates flexible? Find out the best times to travel from St. Louis to San Juan based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking St. Louis to San Juan flights

  • How many flights are there between St. Louis and San Juan Luis Munoz Marin Intl Airport per day?

    There is a maximum of 1 nonstop flight a day that takes off from St. Louis and lands in San Juan Luis Munoz Marin Intl Airport, with an average flight time of 4h 25m. The most common departure time is 9:00 am and most flights take off in the morning. Each week, there are 1 flights.

  • What is the cheapest flight from St. Louis to San Juan Luis Munoz Marin Intl Airport?

    In the last 3 days, the lowest price for a flight from St. Louis to San Juan Luis Munoz Marin Intl Airport was $161 for a one-way ticket and $336 for a round-trip.

  • Do I need a passport to fly between St. Louis and San Juan?

    Yes, you'll most likely have to show a valid passport before boarding the plane in St. Louis and on arrival in San Juan.

  • Which aircraft models fly most regularly from St. Louis to San Juan?

    The Boeing 737-800 Passenger/BBJ2 (winglets) is the aircraft model that flies most regularly on the St. Louis to San Juan flight route.

  • Which airline alliances offer flights from St. Louis to San Juan?

    Star Alliance, SkyTeam, and oneworld are the airline alliances operating flights between St. Louis and San Juan, with Star Alliance being the most commonly used for this route.

  • On which days can I fly direct from St. Louis to San Juan?

    You can catch a nonstop flight from St. Louis to San Juan on Saturday.

  • Which is the best airline for flights from St. Louis to San Juan, Southwest or Delta?

    The two airlines most popular with KAYAK users for flights from St. Louis to San Juan are Southwest and Delta. With an average price for the route of $514 and an overall rating of 7.9, Southwest is the most popular choice. Delta is also a great choice for the route, with an average price of $383 and an overall rating of 7.9.

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

    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 San Juan.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to San Juan from St. Louis 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 San Juan?

    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 to San Juan with an airline and back to St. Louis with another airline. Booking your flights between St. Louis and SJU can sometimes prove cheaper using this method.

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

    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 to San Juan from St. Louis up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Prefer to fly direct from St. Louis to San Juan?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from Lambert-St Louis to San Juan Luis Munoz Marin Intl.
Find which airlines fly direct from Lambert-St Louis Airport to San Juan Luis Munoz Marin Intl Airport, which days they fly and book direct flights.

Direct departures

Lambert-St Louis to San Juan Luis Munoz Marin Intl

Saturday

Southwest

Southwest

See more direct flights

Direct returns

San Juan Luis Munoz Marin Intl to Lambert-St Louis

Saturday

Southwest

Southwest

See more direct flights

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

 
See real verified KAYAK customer reviews for airlines flying from St. Louis to San Juan. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from St. Louis to San Juan? 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
SouthwestOverall score based on 4277 reviews
8.6Crew
8.1Boarding
7.5Entertainment
7.0Food
8.0Comfort
Airline reviews

The first time I flew in the extra legroom section. It was difficult to notice a difference. I had bad luck with my neighbors. The crew was okay. Southwest has reduced the live TV options.

4.0 OkayAnonymous, May 2026
MDW - LAX
Read more Southwest reviews

The first time I flew in the extra legroom section. It was difficult to notice a difference. I had bad luck with my neighbors. The crew was okay. Southwest has reduced the live TV options.

The flight was smooth. The Southwest experience has degraded overall, but this one was okay.

No gluten free snacks. Seats felt worn or bare bones even though it was a new 737 MAX 8.

One major problem that was very unprofessional and uncalled for. Plane landed and we had to wait 20 minutes to get off the plane since they were waiting for someone to come to the gate to drive the jetway. Southwest couldn't have someone available and waiting for the plane to land? Is there only one person in Hobby airport who knows to drive the jetway? Was he at lunch? In the bar? Uncomfortable and uncalled for!

The checking experience in Orlando was terrible, almost missed the flight. Too many travelers and Southwest completely understaffed.

I'm glad it wasn't only 75% full because I could get a good seat

if I was good. Not happy that I have to pay extra money to get the seat I need for lake room, but I guess that’s a sign of the times.

Seats were very comfortable. They tilted back. Drinks and snacks were free and served 3 times. Attendants were awesome.

Plane was clean and comfortable. Flight attendants and gate staff were professional, friendly and efficient. Boarding and deplaning were orderly and efficient. All in all, the typical excellent Southwest experience.

Truly terrible. Will never willingly fly southwest again. Seats are worse than before they switched to assigned seating. One flight attendant was the opposite of helpful (rude, unhelpful, dismissive, and as my stranger seatmate said unprompted: a total prick). This caused me, 15 minutes into the flight, to book an alternate return flight home on a competing airline (first class 1.2k purchase instead of my existing planned flight) just so I would not have to ever be on that aircraft, with that terrible service person, with those horrific seats ever again.

I continue to be satisfied with Delta’s excellent service out of LGA. The digit id works well and gets me through security in no time. Whenever possible, I choose Delta.

Was revoked with Jet Blue due to delay from Kenya Air

The Boarding process was great. Particularly since my wife and I require assistance. The flight attendants were amazing. We travel frequently; they honestly were a cut above. 😀

Enjoyed it very much. Especially liked the free WiFi that Delta offers.

Smooth flight. Left on time, and got in 15 minutes early. Onboard video was great

For some reason, TSA Atlanta didn’t have my bag on the flight on time and they don’t have to provide Delta a reason for that.

WiFi didn’t work on two of four planes. Flight attendants were not overly friendly or welcoming. Planes were extremely slow to board and deplane.

Delta does a great job with entertainment and free wifi. I can still be in touch with my colleagues while in the air.

Aside from a completely packed plane, I really have no complaints.

Bus to plane was delayed for no apparent reason and our luggage was still on the belt when they shut it off. Took about 20 minutes to turn it back on to get our luggage.

We had a delay, but thankfully I made it to my connection. Overall it went smooth

The flight had a delay but I made it to my connection. Flight was smooth overall

As I wrote earlier, poor planning and/or communication. At least twice, we were told that we would be boarding in less than ten minutes, only to have the flight again delayed at least another hour.

This flight is a quick way to get to Chicago, but a bit expensive.

Very comfortable seating and the Flight staff were very attentive. The premium economy section that I was seated in was very clean, updated, and well appointed. I would highly recommend flying United Airlines as this experience was better than the Japan Airlines business class that I flew several months ago.

Our flight was canceled same day and we were never informed. Had to pay more and worse seating on another airline.

Our flight to Rome, Italy was cancelled the day of and we were never informed. We only found out because I was trying to get into my husbands account and called to get his account number. Had to pay more for worse seating on another airline.

My service dog and I were asked to deplane just before they closed the door - clearly very last minute they couldn’t find the documentation that I have filled out many many times before that is for flying service animals. I purposely purchase 3seats (a whole row) since he is large and not all passengers want to sit next to a dog on a cross country flight. The plane departed with my husband on it!!! They made me fill out a hard copy of the same form and had to reschedule me on a later flight where they could find 3 seats together!! I’ve done this so many times before - clearly the error was on their part in a technology glitch - but really people - do better!! Very traumatic - and my husband had to wait for us when he landed ….so bad. Poor pup was confused and tired.

First class ticket gets you no seat back entertainment? I have to bring my own laptop to see a movie? And most of their movies have ADS? No thank you. Worse: Tiny snacks only on a 2 hr flight?

Late- that’s what United does best. Missed my connection, rebooked to a flight 17 hours later and had to spend $500 on a hotel. What did I get? A $15 meal voucher. What can you get in an airport for $15. I hate United so much.

Requested early boarding to disinfect seat, tray table, etc. before general boarding. Instructed to board after wheelchair passengers. Waited on jet bridge behind 12 wheelchair passengers. Stopped immediately after entering plane to wait for gate agent in rear of plane cleaning a seat that was wet, got to my row and found both seats adjacent to mine already occupied, with the lack of room making it impossible for me to clean my own space and defeating the purpose of my boarding early. Cleaned the armrests and tray table as best I could.

Seat bottom cushions are not good. I’m 165# & they hurt my butt. Plenty of legroom.

The wifi experience is awful. I had to try again and again, taking over 30 minutes, to connect to the wifi. I had to watch the same two ads over and over until I was finally successful. Once connected, it was anything but "high speed" and disconnected at least three times during the flight.

Fine. Nothing to write home about. The plane left on time, and arrived on time.

I was downgraded from first class to coach due to an airplane change. They pulled me out of line and I was the very last person to board the plane stuck in the middle seat with no overhead place to put my carry-.on. Very poor customer service.

Seat comfort was poor (no lumbar or lower back support).

The airplane seats were spacious and comfortable, and the flight attendants were friendly and attentive. The food was delicious like never before. The blankets and toiletries were thoughtfully provided. The captain's navigation was steady and reliable. In short, having flown with Starlux, I won't consider any other airline next time.

STOP MAKING THE SEATING SO CRAMPED. WE NEED A PASSENGER BILL OF RIGHTS!

The passenger in front of of me reclined their seat back all the way the entire flight. Their headrest was in my face the entire flight! I barely had room for the little plastic cup of water to fit on my tray table; can you make the seats and space between the rows any smaller??? You can’t even get up to use the restroom! Worst flight I’ve had in a very long time!

We had several flights and they were all on-time and flawless

There weren't enough employees at check in took awhile to get bags checked. There wasn't a wheel chair for me, I was sent to someone who turns out to work for a different airline, if My flight hadn't been delayed I probably would have missed my flight as it was, by the time I arrived at my gate, they started boarding in about 15 minutes. I don't know who took me to my gate, definitely was not the normal people who take passengers to the gate. I'm guessing she may have been in a management position. I wish I knew her name, she went beyond to help me. With that said everyone was kind, and were doing the best they could. So, I choose to say it was an Adventure, stressful start, but good. In the end went well. The situation was not only difficult for passengers but the employee's.

The staff at the check in counter was so rude. Made you feel Incompetent

Frontier scheduled a 40 minute connection in DEN. What they failed to mention was that they “close the doors” 20 mins prior to departure, which means you only have 20 mins. Not enough time. Possibly against DOT regulations. Filing complaint.

Flight was scheduled at 9:40pm. Got delayed to 10 am, the next day. crazy

The bag check, flight check-in, and onboard experience convinced my wife and me that we will actively go out of our way to avoid flying Frontier Airlines in the future. At bag check, we were informed that check-in could only be completed via the Frontier mobile app. Unfortunately, the app was extremely frustrating—sending us through repetitive, confusing loops that repeatedly forced us to decline add-on services with nearly every click. While most airline apps upsell, this one felt intentionally exhausting. As the process dragged on, we became genuinely concerned that my phone battery would die before check-in could be completed. We approached the bag check staff—who were standing together talking—and explained both our frustration and our predicament. They laughed. Later, my wife described the interaction as “gaslighting,” which felt accurate. We were then informed it would cost $25 per person simply to have our boarding passes printed. From that point forward, the tone of the experience was consistently hostile. The bag check employees were condescending and combative, behaving more like bullies than customer service staff. Unfortunately, that same attitude continued onboard. One flight attendant argued with me when I attempted to stow my backpack in the overhead bin. I explained that we had each paid $75 to check our bags specifically so we would not need to use carry-on space and could have adequate legroom. She demanded to see my ticket, pointed out that it said “no carry-on”—which I acknowledged—and I reiterated that this was precisely why we paid to check our bags. Her response was, “I don’t make the rules.” She then walked away, but not before asking if I “truly wanted to fly back to Chicago today?”—an unnecessary and unmistakable threat. It is also worth noting that despite booking our tickets together in the same transaction, we were not seated together. Upon our return to Chicago—where we could once again sit together—we compared onboard experiences. We both remarked on how unhappy the flight attendants appeared and how each of us was separately asked whether we would like to purchase a beverage. We declined. At no point was water mentioned as an option, leaving us with the clear impression that even water came at a cost—or that complimentary water, if available at all, was deliberately left unmentioned. Overall, the experience was shocking and deeply disappointing, but it was also a profound learning experience—one we will not forget and will not repeat. -Steve

Plane was hot and miserable and the crew was rude!

12 hour delay required getting on and off plane 3 times - would have at least liked to have been offered a snack or drink

They didn’t offer a water, even after I asked

They switched our terminal 3 times and we were delayed for four plus hours!!!

It was an early flight and most people napped/slept and the crew let us which was nice.

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

Information on your arrival and departure airports