STL - SJU

$87 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 4/20. 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.
Travelers love KAYAK
41.299.237 searches in the past 7 days on KAYAK

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Everything you should know

Cheapest round-trip
$263
Overall average: $345
Frontier
Mon 4/20Mon 4/27
STL - SJU • 1 stop
Cheapest one-way
$87
Typical prices: $165-$286
Frontier
Mon 4/20
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 $263 (round-trip)
Best reviews • 8.0 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 07m (one-way)
Insights
Insights
Insights
Insights
Avoid delays
Most punctual • 78% on-time
Best time • Fewest delays
Insights
Insights
Insights
Insights
When to travel
Cheapest • 49% price drop
Most popular
Good to know
Good to know
+1
+1
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

Mon, Apr 20 - Mon, Apr 27
Frontier Logo
4:59 pm - 2:01 am
STL
-
SJU
8h 02m
1 stop
Frontier Logo
3:08 am - 11:19 pm
SJU
-
STL
21h 11m
1 stop
$263Frontier
Sat, May 2 - Sat, May 9
Frontier Logo
4:59 pm - 10:39 am
STL
-
SJU
16h 40m
1 stop
Frontier Logo
6:00 am - 12:21 am
SJU
-
STL
19h 21m
1 stop
$266Frontier
Tue, Apr 28 - Sat, May 2
Frontier Logo
4:59 pm - 2:01 am
STL
-
SJU
8h 02m
1 stop
Frontier Logo
3:26 pm - 11:19 pm
SJU
-
STL
8h 53m
1 stop
$271Frontier
Tue, Aug 11 - Wed, Aug 19
Frontier Logo
3:33 pm - 4:55 am
STL
-
SJU
12h 22m
1 stop
Frontier Logo
6:25 am - 2:48 pm
SJU
-
STL
9h 23m
1 stop
$276Frontier
Tue, Apr 7 - Wed, Apr 15
Frontier Logo
4:59 pm - 2:01 am
STL
-
SJU
8h 02m
1 stop
Frontier Logo
3:19 pm - 11:19 pm
SJU
-
STL
9h 00m
1 stop
$281Frontier
Sun, Apr 26 - Thu, Apr 30
American Airlines Logo
7:12 am - 11:02 pm
STL
-
SJU
14h 50m
1 stop
American Airlines Logo
1:31 pm - 11:46 pm
SJU
-
STL
11h 15m
2 stops
$282American Airlines
Fri, Apr 10 - Mon, Apr 13
Frontier Logo
4:59 pm - 8:49 pm
STL
-
SJU
26h 50m
1 stop
Frontier Logo
5:45 am - 11:25 pm
SJU
-
STL
18h 40m
1 stop
$291Frontier
Sun, Apr 26 - Thu, Apr 30
Frontier Logo
4:59 pm - 9:54 am
STL
-
SJU
15h 55m
1 stop
Frontier Logo
3:39 pm - 11:19 pm
SJU
-
STL
8h 40m
1 stop
$292Frontier
Mon, Apr 20 - Sun, Apr 26
Frontier Logo
4:59 pm - 9:54 am
STL
-
SJU
15h 55m
1 stop
Frontier Logo
3:21 am - 11:19 pm
SJU
-
STL
20h 58m
1 stop
$293Frontier
Thu, May 14 - Sun, May 17
Frontier Logo
4:19 pm - 8:04 am
STL
-
SJU
14h 45m
1 stop
Frontier Logo
6:09 pm - 12:21 am
SJU
-
STL
7h 12m
1 stop
$294Frontier
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.

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 November, where the average cost of round-trip tickets is $615 and $502 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$87
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

  • 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 $87 for a one-way ticket and $263 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 $515 and an overall rating of 8.0, Southwest is the most popular choice. Delta is also a great choice for the route, with an average price of $390 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.
8.0
SouthwestOverall score based on 4331 reviews
8.6Crew
7.5Entertainment
7.0Food
8.1Boarding
8.0Comfort
Airline reviews

Great flight. Good snacks and drinks. Grateful it was free. The flight from Nashville to louisville, i think her name was Tracy (not sure that's right) super awesome, nice and cheerful. She really enjoyed being at work today! She was the person who scanned the boarding pass on flight wn941. She should be recommended for a raise !

10.0 ExcellentGwen, Mar 2026
DAL - BNA
Read more Southwest reviews

Great flight. Good snacks and drinks. Grateful it was free. The flight from Nashville to louisville, i think her name was Tracy (not sure that's right) super awesome, nice and cheerful. She really enjoyed being at work today! She was the person who scanned the boarding pass on flight wn941. She should be recommended for a raise !

I liked it better when you were truer to your roots Am paying more for less fun

Southwest was greaat! The most expensive but the least upsetting for those we were flying to see.

I flew twice this week on Southwest, was delayed over 2 hours both ways. From Pittsburgh to Chicago it was due to weather but the gate agents, pilot etc were great at updating everyone. Today from Midway to Pittsburgh the plane had come from an international location, kept getting delayed, no information was given until we were delayed for the third time. It was ridiculous, whoever scheduled that plane to fly to Pittsburgh after didn’t consider a lot of things.

Boarding was easy. The seats are small and fairly uncomfortable

I was supposed to be on a later flight. When I showed up at the gate, the woman working there was extremely helpful getting moved up to this earlier flight.

We had a 5 hour delay on the tarmac in Baltimore

Long layover between flights to Long Island from BWI - need better coordination between flights

I elected to pay for the upgrades and found very little difference

The new seating arrangement is so over priced for what you get.

As previously noted, this flight was great: departure was timely, the crew was friendly and attentive, and wifi connectivity was seamless. In particular, I appreciated that the flight attendant just told me to stow the laptop right before takeoff/landing, and trusted me to do so (which I did!).

Kayak botched up the booking, i had to call delta and fix. In the process Delta failed to honor my comfort plus seat assignment that i had previously.

Entertainment is ok! Boarding and seat with zone is terrible. I paid for the seats but you didn’t give me what I paid for which is exit isles.

the crew cancel the morning service due to the weather. Then the flight got deverted to Nashville . we were on the ground for over two hours the only gave us water once... no food or any snacks.... the crew should have handled better and offered something to passengers.

My recent experience was excellent on Delta! I flew with Delta Comfort and I was really comfortable in my seat. I enjoyed the in-flight service. The flight attendants were so friendly and hospitable. I love the snack on the flight as well. This was my first time flying on Delta and I will definitely consider flying with them again.

My flight was cencaled due with the bad weather on Sunday the crew was poorly mistaken my luggage supposed depart with my flight instead I didn’t have my luggage for almost 3 days the website is poorly respond to my complain until I have someone to do it my connection smooth their not even respon or email me even the have my luggage

Delta needs to step its game up get a more reliable internet service. Internet service was non-existent for this flight.

Mechanical Delay of over an hour with multiple gate changes. Entertainment system down for rejuvenation.

This was a Latam operated flight. Seats seemed a bit narrow in business class. Older aircraft.

I had a flight cancel and had it rerouted. When the rerouted they put me at a window seat instead of an isle. It was hard sitting by the window because the couple with masks on were making out. I get motion sickness which is why I need to have the isle seat.

I will never fly ANA again. They lost one of my large pieces of checked luggage, the heaviest one with the most valuable items in it, and they said they will not send me an email unless they can't find it, even though the paper they gave me to track the status of my lost luggage requires a code from an email they are supposed to send me so I can do baggage tracing. They claim to be an international airline, but they also insist on calling a Japanese telephone number to confirm where to send the lost baggage if they find it. It is impossible to find an actual contact email address for customer support on their website, and their AI chatbot is unhelpful, directing you to a webpage that says it is for contact information but does not have any actual email addresses or phone numbers listed on it. My seat in economy did not recline at all, even though I was not sitting in an exit row nor the very back row. I had to sit in the fully upright position for over ten hours of international travel. Awful experience overall.

No seat back entertainment. And app had a hard time getting entertainment loaded.

ticket agent lady wás very helpful , she arranged wheel chair for my elderly mother

Didn't make the flight because the first leg of my flight was canceled and the next leg was already booked.

My flight was canceled a few hours before boarding. I was rebooked on Copa airlines and missed an important meeting .

Good quick flight on a small but comfortable plane. I'm 6'3 and had plenty of space.

Experience was great - no complaints. Took off on time, landed early. Got to the gate relatively quickly - took a little bit of extra time to deplane but nothing excessive.

Business class seats felt very cramped compared to other airlines.

Economy plus was so cramped I could not use my laptop. It was beyond bad.

OK, we were delayed and had to de plane and reboard.

A first class seat should fit a fat person, and this doesn't. The trays in the armrest are less functional than an ordinary tray in the back of the seat.

The flight attendant was friendly and efficient. The temperature was kept nice and cool. The plane was nice, but filthy. There were visible spills on my tray table. The gate agent was somewhat rude with her announcements and in speaking with other customers.

I appreciate that I finally got the seat I paid extra for this time. Thank you

I would have liked a pillow. The vegetarian wrap and oaten cake was good.

I would have liked vegetarian and gluten free options for evening dinner time flight. I would have like a pillow on the international overnight flight . The veg wrap and oaten desert on the international flight was good

The experience at checkin for my American Airlines flight from Sacramento to LAX was very good including the assistance I received in getting my bags checked in and boarding passes printed. Was pleasantly surprised the my bags were checked through all the way to my destination at Clark International Airport in Angeles, Philippines.

Absolutely terrible. Would never fly American again. 2 deplaned incidents and delayed by close to 24 hours. $12 meal voucher for first class passengers was an insult to the injury. Pathetic.

Terrible planning. And even worse gate agents. Absolutely rude behavior.

Half of the TSA checkpoints at PHL are closed. Also, there is no standby for first class passengers. You can only standby for coach. Very dated policy and inconsistent with peers.

Flight was scheduled at 11:26am but they keep Delaying until midnight. They waited at airport restless.

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!!!

My flight was originally from SAT to MCO connecting from MCO to ORD. We got diverted to ATL and than Frontier staff there was sooo un helpful first they said they couldn’t give us any accommodation since our flight first got delayed that cancelled and now it’s 221am and I am still in ATL since they said they need to create a new flight my final destination is ORD and I have been delayed twice and cancelled. With no real help the frontier app didn’t work no email updates over all such a horrible experience

There's no seats that lean back with little leg space i wad uncomfortable the entire flight. Your charges for extra baggage is despicable and costly!!

Remind customers of the need to have passport or new ID for boarding.

Flight was canceled. Most upsetting was message from Kayak, stating that the flight was canceled and click with Kayak for details regarding rebook, refund details. THERE'S NO INFORMATION PROVIDED BY KAYAK EXCEPT THAT FLIGHT IS CANCELED. AND NOW THIS SURVEY TO FIND OUT HOW WAS THE FLIGHT !!!!!!!

The flight never took off and we spent 7 hours at the airport

Gate not determined until I got to the airport - hard to plan the trip to the airport.

Our flight was canceled. I will never use Kayak nor Frontier for travel again. The entire experience was a headache.

Frontier.. nickel and dime add-ons. Flight late, on time, late again, last minute gate change, arrival gate required a shuttle to the terminal. They sure keep you guessing.. if you like a little chaos and airport anxiety, this is the airline for you!

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

Information on your arrival and departure airports