STL - SJU

$131 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 7/25. 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
$236
Typical prices: $545-$286
Frontier
Wed 8/5Wed 8/12
STL - SJU • 1 stop
Cheapest one-way
$120
Typical prices: $167-$278
Frontier
Sat 7/25
STL - SJU • 1 stop
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 $236 (round-trip)
Best reviews • 7.9 score
Airline reviews
Airline reviews
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Airline reviews
Airline reviews
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Top layover airports
Cheapest • Avg $269 (round-trip)
Shortest trip • 7h 16m (one-way)
Insights
Insights
Insights
Insights
Avoid delays
Most punctual • 70% on-time
Best time • Fewest delays
Insights
Insights
Insights
Insights
When to travel
Cheapest • 48% 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

Wed, Aug 5 - Wed, Aug 12
Frontier Logo
4:09 pm - 7:57 am
STL
-
SJU
14h 48m
1 stop
Frontier Logo
6:31 pm - 11:59 pm
SJU
-
STL
6h 28m
1 stop
$236Frontier
Sat, Aug 1 - Mon, Aug 10
Frontier Logo
4:09 pm - 2:11 am
STL
-
SJU
9h 02m
1 stop
Frontier Logo
6:00 am - 11:59 pm
SJU
-
STL
18h 59m
1 stop
$240Frontier
Wed, Aug 19 - Sun, Aug 23
Frontier Logo
4:10 pm - 1:54 am
STL
-
SJU
8h 44m
1 stop
Frontier Logo
4:05 pm - 12:14 am
SJU
-
STL
9h 09m
1 stop
$256Frontier
Sat, Jul 25 - Fri, Jul 31
Frontier Logo
3:34 pm - 5:02 am
STL
-
SJU
12h 28m
1 stop
Frontier Logo
4:05 pm - 11:59 pm
SJU
-
STL
8h 54m
1 stop
$258Frontier
Thu, Jul 23 - Mon, Jul 27
Frontier Logo
4:09 pm - 2:11 am
STL
-
SJU
9h 02m
1 stop
Frontier Logo
6:31 pm - 11:59 pm
SJU
-
STL
6h 28m
1 stop
$276Frontier
Tue, Aug 4 - Mon, Aug 10
Frontier Logo
4:09 pm - 5:36 pm
STL
-
SJU
24h 27m
1 stop
Frontier Logo
3:06 am - 11:59 pm
SJU
-
STL
21h 53m
1 stop
$301Frontier
Thu, May 28 - Fri, Jun 5
Frontier Logo
6:33 pm - 11:59 pm
STL
-
SJU
28h 26m
2 stops
Frontier Logo
5:15 pm - 8:55 am
SJU
-
STL
16h 40m
1 stop
$304Frontier
Wed, Aug 19 - Wed, Aug 26
Frontier Logo
4:10 pm - 1:16 pm
STL
-
SJU
20h 06m
1 stop
Frontier Logo
6:41 pm - 5:30 pm
SJU
-
STL
23h 49m
2 stops
$316Frontier
Sat, Jul 25 - Mon, Aug 3
Frontier Logo
4:52 pm - 2:16 pm
STL
-
SJU
20h 24m
1 stop
Frontier Logo
7:30 am - 5:37 pm
SJU
-
STL
35h 07m
2 stops
$317Frontier
Sun, Jul 19 - Tue, Jul 28
Frontier Logo
6:33 pm - 12:28 am
STL
-
SJU
28h 55m
2 stops
Frontier Logo
5:15 pm - 8:57 am
SJU
-
STL
16h 42m
1 stop
$318Frontier
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 $219 (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 $500 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 11 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$120
Best time to beat the crowds with an average 49% drop in price.
Most popular time to fly and prices are also 5% 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 $131 for a one-way ticket and $236 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 $520 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 $382 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 4305 reviews
8.6Crew
7.0Food
8.1Boarding
8.0Comfort
7.5Entertainment
Airline reviews

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.

2.0 MediocreJoshua, May 2026
TPA - LAS
Read more Southwest reviews

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.

Not having a five hour delay with little notice! The crew was very kind, though, and just as tired as we passengers were. The flight didn't depart until nearly 1 am...and no reason was ever given.

The entire experience from boarding to landing was amazing! The crew were very friendly. Will definitely be back.

no service at all due to turbulence. they should've at least given us snacks, there were only 10 people on the entire flight.

First time I've had to use the disabled accommodations. And I could not have had a better experience with Southwest, i was having trouble getting from one terminal to another due to my heart failure. And the next thing I know a Southwest agent had made sure. I had a wheelchair at all my flights. Can't thank them enough.

Delayed flight, lack of information, boarding process is a mess as is the carryon luggage causing issues when leaving the plane….just a poor experience.

Comfortable. Easy. No problems. Just wish they had gf options for snacks.

The crew was very kind and made going to Hawaii relaxing and fun to look forward to! Thank you Southwest for a pleasant flight!

This leg was much better, but we did have to have a 3 hour lay o er after coming from a very exhausting hiccup with our flight from BNA to Den

We waited in the airplane for over 45 min for a southwest employee to make the flight. This cause over half the plane to miss their connecting flight in Denver. When we confronted the desk upon arrival, they told us the only flight they had was the next day leaving at 8:50 pm!!! Or they offered to get us to Burbank or LA, but after that we were on our own to get back to Santa Barbara. I paid for a flight from sba to bna bna to sba. My re entry into mom mode has been 💯 rough because of southwest mistake with my flight. And now I’m leaving to Reno tomorrow for a vballl tournament and just discovered that my leg in Vegas has me and my 3 kids on a stand by flight even though I had booked these ticket last year November!! Do better southwest!

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.

WiFi didn’t work. Flight delayed 3 hours Crew members were illiterate Seat lean back did not work.

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.

Super friendly with lots of drink options an entertainment. Friendly crew.

Standard flight with a drinks and a snack- overall very quick flight. The flight attendants were very strict, bordered on rude.

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

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.

The crew acted like they had never done this and kept barking passive aggressive orders at people. + the security line + the delay + sitting on the tarmac for 2 hours + none of the apps or signage updating with correct times

More inflight connection. And leg space is horrible. And the paying for baggage I'd ridiculous!!!

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

Information on your arrival and departure airports