STL - SJU

$129 Find Cheap Flights from St. Louis to San Juan - Compare and Save

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 9/24. 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, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to San Juan, as well as popular online travel agencies
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Everything you should know

Cheapest round-trip
$327
Typical prices: $336-$570
Southwest
Sat 11/7Sat 11/14
STL - SJU • Non-stop
Cheapest one-way
$129
Typical prices: $176-$573
Frontier
Thu 9/24
STL - SJU • 2 stops
Nonstop flights
1 day a week
Sat
You can fly direct with Southwest. Average duration is 4h 25m
Direct flights
Direct flights
+1
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Direct flights
Direct flights
+1
Top airlines
Cheapest • from $327 (round-trip)
Best reviews • 7.9 score
Airline reviews
Airline reviews
+1
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Airline reviews
Airline reviews
+1
Top layover airports
Cheapest • Avg $269 (round-trip)
Shortest trip • 7h 10m (one-way)
Insights
Insights
Insights
Insights
Avoid delays
Most punctual • 69% on-time
Best time • Fewest delays
Insights
Insights
Insights
Insights
When to book
in advance
Our data shows that travelers who book at least 3 weeks in advance save around 17% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
Cheapest • 29% price drop
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
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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

Sat, Nov 7 - Sat, Nov 14
Southwest Logo
10:55 am - 5:15 pm
STL
-
SJU
4h 20mnonstop
Southwest Logo
10:55 am - 1:55 pm
SJU
-
STL
5h 00mnonstop
$327Southwest
Fri, Sep 18 - Sat, Sep 19
Southwest Logo
11:40 am - 10:50 pm
STL
-
SJU
10h 10m
1 stop
Southwest Logo
5:05 am - 11:05 am
SJU
-
STL
7h 00m
1 stop
$331Southwest
Sat, Nov 7 - Sat, Nov 14
Southwest Logo
10:55 am - 5:15 pm
STL
-
SJU
4h 20mnonstop
Southwest Logo
1:30 pm - 7:35 pm
SJU
-
STL
8h 05m
1 stop
$332Southwest
Fri, Sep 18 - Sun, Sep 20
Southwest Logo
2:25 pm - 10:10 pm
STL
-
SJU
6h 45m
1 stop
Southwest Logo
5:30 am - 11:50 am
SJU
-
STL
7h 20m
1 stop
$336Southwest
Wed, Sep 2 - Wed, Sep 9
American Airlines Logo
10:44 am - 9:55 pm
STL
-
SJU
10h 11m
2 stops
American Airlines Logo
2:58 pm - 10:42 pm
SJU
-
STL
8h 44m
2 stops
$341American Airlines
Mon, Aug 10 - Fri, Aug 14
Frontier Logo
4:57 pm - 12:41 am
STL
-
SJU
30h 44m
2 stops
Frontier Logo
10:48 pm - 11:59 pm
SJU
-
STL
26h 11m
1 stop
$345Frontier
Fri, Aug 14 - Sat, Aug 22
Frontier Logo
4:57 pm - 12:41 am
STL
-
SJU
30h 44m
2 stops
Frontier Logo
9:16 am - 4:11 pm
SJU
-
STL
7h 55m
1 stop
$346Frontier
Sat, Aug 8 - Tue, Aug 11
Frontier Logo
4:57 pm - 12:41 am
STL
-
SJU
30h 44m
2 stops
Frontier Logo
12:13 pm - 11:59 pm
SJU
-
STL
12h 46m
1 stop
$348Frontier
Sun, Aug 2 - Fri, Aug 14
Frontier Logo
6:34 pm - 2:00 pm
STL
-
SJU
42h 26m
2 stops
Frontier Logo
10:48 pm - 11:59 pm
SJU
-
STL
26h 11m
1 stop
$356Frontier
Wed, Aug 5 - Tue, Aug 11
Frontier Logo
4:09 pm - 2:15 am
STL
-
SJU
9h 06m
1 stop
Frontier Logo
6:26 am - 8:57 am
SJU
-
STL
27h 31m
2 stops
$357Frontier
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 November.

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 $298 (return) on average. On the other hand, the most expensive months are December and July, where the average cost of round-trip tickets is $606 and $490 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 3 weeks before departure, which saves you about 17% compared to booking last minute. 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$129
Best time to beat the crowds with an average 30% 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 5 days, the lowest price for a flight from St. Louis to San Juan Luis Munoz Marin Intl Airport was $129 for a one-way ticket and $327 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 737-700 Passenger/BBJ1 (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 $487 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 $384 and an overall rating of 7.8.

  • 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.

KAYAK’s top tips for finding a cheap flight from St. Louis to San Juan Luis Munoz Marin Intl Airport

  • Looking for a cheap flight? 25% of our users found flights on this route for $458 or less round-trip.

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 4246 reviews
7.5Entertainment
8.1Boarding
8.6Crew
8.0Comfort
7.0Food
Airline reviews

Snacks are always pretzels. Why can't you also offer peanuts ?

6.0 GoodAnonymous, Mar 2026
STL - HOU
Read more Southwest reviews

Snacks are always pretzels. Why can't you also offer peanuts ?

Only downside was the legroom and seat width, which is always a problem unless I spend more for a premium seat.

Very good. Sad to learn Southwest is going start to charge for bags

Exceptional crew! Friendly and professional. Pleasant attitude and treated everyone with respect.

The flight was promptly on schedule and Southwest delivered everything they promised. No excuses for any shortfalls just 100% ownership of their responsibilities and business. The boarding and seating policy is a complete shambles. What started out as a great idea when Southwest first hit the market has been turned into a disaster due to the lack of integrity in many of the people who fly Southwest and take advantage of Southwest generosity at the expense of their fellow passengers.

Crew was excellent - Plane was fine. Media was good, could use more kid shows; Not a fan of the brownie brittle -- snack could be slightly better.

it was great. the crew is exceptional. the flight was on time.

Left on time and arrived early. Brand new plane and no parts missing. Comfortable seats. The actual Captain spoke prior to the flight and reassured everyone about safety. Crew was so nice and fun. Perfect flight!

Everything went smoothly and the plane wasn’t full. It was delayed though. The delay was increased due to a crew change which was frustrating.

Love Southwest! Always a good trip with a happy crew who goes out of their way to be kind and fun.

From checking to boarding, it was a seamless experience. The service agents were so helpful. The flight crew was so pleasant.

Delta has too many delays now days. It is 1:06 am now. I was supposed to land in Norfolk at 10:30 pm. I got re-booked through Detroit and I’m still in Detroit. I hope to be landed in Norfolk by 3am. I’ve been in airports for 12 hours as of right now. There is a weather delay now but most delays lately have been maintenance.

It was good. The leg room was not great in Row 1.

Great flight with Delta! Boarding was quick and easy, the amenities were solid, and the plane was in great shape. The flight attendants had a fun, lively energy while staying professional. All in all, a smooth trip — even managed to catch up on some rest. Thanks, Delta!

My flight was canceled after being rescheduled for four days canceling my trip. Kayak and everyone affiliated with it I.e the airlines, and just fly have been excruciating to deal with. My trip to visit family had to be canceled as there was no way to make it. I am furious at all of you.

They delayed our flight because of bad weather in NY which was completely understandable. Then they cancelled our flight and a later flight that evening. The earliest we could fly was the next morning. We ended up buying last minute tickets on another airline and made it home slightly delayed but safely that evening. Delta kept saying it was weather related but if that was the case how did we make it back on another airline? The weather in NY was cloudy but not bad.

The plane smelled like a sewer. Multiple passengers complained. It’s a safety and quality issue to clean these planes.

When we checked in my friend and I were sitting seperate. By the time we got to boarding, they automatically switched our seats. I really liked that.

We were delayed 2 hours leaving STL. I had 20 mins from when we landed in SLC terminal A to make it to SLC terminal B. I had to actually run! thankfully I made my flight but 3/4 legs were delayed to some capacity.

I trust Delta. I travel comfortable. The snacks could improve or could go to something as a little sandwich.

Fine not above and beyond as I had a connection that was delayed due to maintenance

HORRIBLE, my initial flight was cancelled, they made me pay $200 extra dollars and that got cancelled as well! After 6 cancellations I decided to get a refund because I needed to get home to my babies. Out of $1000+ dollars they offered me only $40 in refund! Totally unacceptable! The flight that they cancelled I was able to fly it on another airline. I had to spend $400 on one way tickets just to get home! I’m still getting the runaround.

Flight was delayed. De-icing took a while. When we landed had to wait for another plane to vacate our gate. Just an overall bad experience.

Flight was delayed only slightly before takeoff due to traffic control. However, the flight arrived early to ORD. Good flight. United has been very reliable for me.

Our flight was understandably diverted to a small regional airport in Laramie, Wyoming due to weather conditions, which I fully recognize and appreciate. However, the low rating stems from the experience that followed: passengers remained on board for over an hour without the option to deplane and stretch, despite the aircraft being stationary. Although the pilot opened the cabin door, only he was permitted to exit. Meanwhile, passengers grew increasingly uncomfortable as warm summer air entered the cabin through the open door, and being in the second row meant we were impacted immediately. While the flight attendants made efforts to keep everyone at ease, I believe allowing passengers to deplane briefly, given the extended delay, would have significantly improved the overall experience.

Overall a very poor experience - booked premium economy tickets but due to last minute flight delays , all my itinery went for a toss and had to fly economy class with no access to lounge or any compensation by united airlines to make up for the flight delays . i had expected better experience than that from united.

My flight was completely full. Making me very stressful with people walking around all the time. I believe airlines can do better for entertain people during the flight.

Onboarding - it would be great to see on the screen what group they were boarding. It was very confusing on who was boarding (even though they called it out) they were not clear and the space to board was strange.

The United website was easy to use and had all the information I needed. I needed to change my flight and it was accomplished easily on line. I was also easily able to upgrade and for a reasonable price. Boarding went smoothly and the flight was in time. The service was good in board but the crew did not seem happy at all. Limited availability of meals - not much choice for purchase and in business class they ran out of one of the meal choices by row 4. .

Older plane. Food was really bad, almost not worth the effort. Huge difference with European based airlines.

Delayed delayed. Poor professionalism. Our seats changed and we pay for them

American delayed the flight for a crew rest period. The delay occurred late in the evening - the earliest i can find is 10:20 pm. With a 6 am flight anyone on the flight would have already have been asleep (unless you are insane, a vampire or on drugs) and at least for me i was already on the way to the airport at 445 am the next morning when i discovered they delayed the flight until 9 am. Given the incoming flight was in the air at 6 pm the evening before this should have been figured out a lot more timely that was there only crew to use. Just frustrating given there is no consideration for customer experience anymore in flying.

Good crew and flight was on time. It’s a small plane with limited overhead luggage space. They said the overhead space was full and I had to check my bag. There was still space when I got on. Waiting for my checked luggage added 30 minutes to my trip. Not the end of the world but also not great.

Trip delayed for 2 hours because of rain. We boarded and have to get down the flight and reboard again.

No enough space plus only allowing one laggage instead of two like other airlines.

Qatar airways ,boarding arrangements at Hamid international airport could been better

The plane was broken so we had to change planes.

Uncomfortable seats and flight attendant was rude as she insisted on waking up my husband to ask him if he wanted a drink. When he said that he was sleeping, she replied “without an attitude “. He was seated at 8c

Two flight changes before the scheduled flight. On the day of the flight, the flight was delayed, which caused the connecting flight to be missed. Then, I was directed to another airport (CUN) and traveled to Tulum. American gave a $12 voucher for lunch. The least expensive item on the menu at a Mexican restaurant was $9.99. Driving to Tulum was a bad auto crash, and traffic was delayed two-plus hours. The bottom line is that we should have been at the hotel at noon, but it ended up at 11:30 PM.

Airlines must do something with overweight people... Maybe reserve a business class seat for them, or you could pay the consequences if someone overweight seat side by side to you in economy.

Crew was kind of grumpy and there was no beverage service at all. Sodas were $4. Disappointing.

First of all we hade waited 3 hours in the airplane waiting to leave. Second the return schedule was changed and it messed up my entire vaction. I won't buy never again another flight and recommend to nobody traveling with them.

The worst. They don’t follow procedure for boarding per group. Flight got delayed for no understandably reasons, they changed our destination from PR to Miami, left us inside a plane for more than 8 hours, then cancelled flight in Miami leaving us stranded. Poorly managed re-accommodation for a new flight and overnight stay so I have to spend in a new ticket and my own hotel room to been able to get to my office next day. Lost 2 days of work and as a doctor, patients loosing their appointments. to other flights and besides

I liked the price of the flight and the chance to buy a seat with no person seated in the middle seat.. Also the flight was right on time.

The flight left over two hours late. They charged me $180 to bring a carry on. There was an error with the spelling of my name and Frontair agent lied that I would need to pay $200 for her to fix the spelling, and pressured me that if I don't do it quick I would lose the flight. I called back and another agent said it costs $75 to fix. All in all, this company is a complete scam.

I took my first and last flight with FRONTIER. The seats are not able to be reclined so it’s not a very comfortable experience when you take a flight of 3 hours or longer. You must pay for your luggage either carry on or check in, so taking all this in consideration at the end what you think you’re saving your paying in services that should be included. Not a beverage in sight. . You’re seriously better off getting on a proper airline such as Delta, AA, United, etc.

Horrible and worse flight ever. Was left at the airport in SJU by my flight to JFK after several delay at Santa Domingo. Will never recommend Frontier to any one. After leaving, frontier customer service ask me to rebook and pay for another flight to from SJU to JFK. Worse airline ever. You pay for everything with frontier airline.

Frontier notifying me earlier of flight delay of over 2 hours.

I have come to accept Frontier as an absolute no-frills airline, paying for everything I want. A 4.5-hour flight should provide me with a complimentary beverage—rather, $4.9x for a soda. Or a bottle of water ought to be extended at no cost. 4 beers are on the menu, but only 1 type of beer is available (at $9.95). Also, so many restrictions to using a voucher from Barclay‘s Credit Card. Finally, try to reach a live agent for Frontier- impossible!

Excellent crew. WE all know Frontier its a low cost airline but the travel time was about 30 minutes and the crew was phenomenal. I was with a group of 10 more and we are enjoy our flight. The only issue was in SJU waiting for the luggage.

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

Information on your arrival and departure airports