STL - SJU

$86 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 1/31. 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
$171
Typical prices: $304-$589
Frontier
週二 2/24週三 2/25
STL - SJU • 1 stop
Cheapest non-stop
$1,646
Southwest
週六 3/14週六 3/21
STL - SJU • Non-stop
Our travelers' advice
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
Top airlines
American Airlines
Cheapest • from $225 (round-trip)
Southwest
Best reviews • 8.0 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
When to book
3 weeks
in advance
Our data shows that travelers who book at least 3 weeks in advance save around 18% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
September
Cheapest • 51% price drop
March
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Nonstop flights
1 day a week
There are direct flights from St. Louis to San Juan 1 day a week: Sat.
Direct flights
Direct flights
Direct flights
Direct flights
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

週二, 2月 24 - 週三, 2月 25
Frontier Logo
3:49 pm - 2:53 am
STL
-
SJU
9h 04m1 stop
Frontier Logo
11:07 am - 10:27 pm
SJU
-
STL
13h 20m1 stop
$171Frontier
週六, 1月 24 - 週三, 1月 28
Frontier Logo
12:12 pm - 9:54 am
STL
-
SJU
19h 42m1 stop
Frontier Logo
8:00 am - 11:33 pm
SJU
-
STL
17h 33m1 stop
$172Frontier
週一, 2月 23 - 週三, 2月 25
Frontier Logo
3:49 pm - 2:53 am
STL
-
SJU
9h 04m1 stop
Frontier Logo
5:25 pm - 10:27 pm
SJU
-
STL
7h 02m1 stop
$176Frontier
週三, 2月 25 - 週一, 3月 2
Frontier Logo
3:49 pm - 12:43 am
STL
-
SJU
6h 54m1 stop
Frontier Logo
5:25 pm - 11:59 pm
SJU
-
STL
8h 34m1 stop
$180Frontier
週四, 1月 8 - 週三, 1月 14
Frontier Logo
3:43 pm - 12:05 am
STL
-
SJU
6h 22m1 stop
Frontier Logo
8:57 am - 10:34 pm
SJU
-
STL
15h 37m1 stop
$181Frontier
週六, 1月 10 - 週五, 1月 16
Frontier Logo
5:11 pm - 2:50 am
STL
-
SJU
7h 39m1 stop
Frontier Logo
3:58 am - 10:34 pm
SJU
-
STL
20h 36m1 stop
$200Frontier
週四, 1月 22 - 週二, 1月 27
Frontier Logo
5:42 pm - 10:24 am
STL
-
SJU
14h 42m1 stop
Frontier Logo
8:00 am - 11:33 pm
SJU
-
STL
17h 33m1 stop
$202Frontier
週五, 1月 23 - 週三, 1月 28
Frontier Logo
5:42 pm - 3:26 pm
STL
-
SJU
19h 44m1 stop
Frontier Logo
8:00 am - 11:33 pm
SJU
-
STL
17h 33m1 stop
$211Frontier
週四, 1月 8 - 週日, 1月 11
Frontier Logo
3:43 pm - 12:05 am
STL
-
SJU
6h 22m1 stop
Frontier Logo
9:23 pm - 8:05 am
SJU
-
STL
12h 42m1 stop
$215Frontier
週六, 3月 7 - 週二, 3月 10
Frontier Logo
4:51 pm - 9:57 am
STL
-
SJU
15h 06m1 stop
Frontier Logo
3:08 am - 7:07 am
SJU
-
STL
28h 59m1 stop
$218Frontier
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 February.

What’s the cheapest day of the week to fly from St. Louis to San Juan?

The average price of all round-trip flights from St. Louis to San Juan Luis Munoz Marin Intl Airport clicked on KAYAK for each day over the last 12 months.

If you are looking for a flight deal from St. Louis to San Juan, look for departures on Wednesdays and avoid leaving on a Saturday, as it's usually the priciest day. When flying back from San Juan, Tuesday is the cheapest day to fly and Saturday is the most expensive.

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 $618 and $526 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 18% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 10 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.
Airports
STL

Avoid peak hours at STL to minimize wait times. Early mornings and afternoons are busiest, so plan your departure accordingly.

SJU

For quick access to San Juan, taxis or Uber are best. They offer a short ride into town, avoiding parking hassles.

Our travel experts
Yulia Denisyuk

Yulia Denisyuk

Expert on STL

Yulia Denisyuk

Yulia Denisyuk

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.

Read more
Gabriel Leigh

Gabriel Leigh

Expert on SJU

Gabriel Leigh

Gabriel Leigh

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.

Read more

Good to know

Low seasonSeptember
Cheapest flight$86
Best time to beat the crowds with an average 51% drop in price.
Most popular time to fly and prices are also 9% 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 $86 for a one-way ticket and $171 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 MAX 8 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 $577 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 $396 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 4253 reviews
7.5Entertainment
8.0Comfort
8.6Crew
8.1Boarding
7.0Food
Airline reviews

Okay, not wonderful. Short flight. Wi-fi didn't work properly. Stuck waiting for a gate to open upon arrival for 20 or so minutes.

4.0 OkayChad, Dec 2025
BNA - PNS
Read more Southwest reviews

Okay, not wonderful. Short flight. Wi-fi didn't work properly. Stuck waiting for a gate to open upon arrival for 20 or so minutes.

They sent a notice that they were boarding an hour early. We had to leave the club and run to the gate. They said sorry, that came from corporate and was a mistake. They did not have enough seating because the flight before it had not taken off on time. They moved our gate and delayed it for an hour.

The boarding and seat assignment system no longer works for me, but I know it is being replaced. Otherwise, I am good with the overall experience.

The lead steward kept singing about "San Francisco" and hotel California---more annoying than humorous....needs work. Flight was smooth and on time.

Still a fan of open seating. Flight was on schedule and arrived on time. The 737 MAX is very comfortable.

Airline travel is always too cramped to really be pleasant, but the cabin crew on this flight did a pretty good job of making up for it by putting on some music during boarding and sprinkling a few funny remarks into the safety briefing and announcements, and just generally being friendly and helpful. It definitely reminded me of why I prefer the in-flight experience on Southwest!

No delays and arrived to destination 30 min early. Staff was super friendly.

San Diego airport is brand new, spacious, airy and very smooth checkin at SW baggage drop.

It was rough. The staff was unprofessional, the choice of on board drinks terrible, it was cramped in space at every airport, they always ran out of overhead bin space so they pressured people to check bags for free or we couldn’t leave on the plane— so I did check my bag to help, and they nearly lost my bag. My bag did not arrive on the luggage belt, another man on my flight and I had to waste our time going to the baggage office to search for our bags. I would only fly southwest again if it was my last choice. Also, my flights were consistently delayed over and over again— at one point they straight up told us we were waiting for the pilot to arrive.

Crew could have been friendlier, maybe I'm spoiled by SW crews. In flight wifi was good. Would be nice to have more food offerings on a 4 plus hour flight

Flight delays both to Detroits and return flight . The flight to Detroit was associated with mechanical difficulty

I am extremely disappointed that delta internal pilot manuals now refer to the Gulf of Mexico as the “gulf of America”. You can bow down to the Orange turd on your own. I will never fly delta again

Wasn't a Delta issue I don't think, but seems there was a Delta flight at each of the 2 Dallas airports at the same exact time, both to Atlanta. I was evidently booked on the one at Love Airport, but the Carey transport shuttle took me to DFW instead and I ended up missing the flight by just a few minutes. Was able to book a Southwest flight from Love Airport, but was a big loss of time and an inconvenience.

Great. I had to modify a flight. That was easy and free. Thank You

I noticed that the planes seem to be outdated. There was no entertainment per se. Also, the waiting area did not have any working electrical outlets

None of the airplane features were available during the flight.

Original flight was cancelled and when i was rebooked by the airline, they couldn't seat me in the same type of seat as I had originally booked (went from window/aisle to middle/middle and one was a bulkhead seat, and other wasn't in the same class)

Lady Pilot was perfect in every way wheels up to wheels down communication, professionalism, excellent on time departure and on time arrival, excellent communication! Fantastic job with Superb attitude!!

The food is terrible. The staff is wonderful. Comfort is good.

Left on time, a bit delayed due to headwinds most of the trip.

The Crew and the food was the worst I ever had in Business Class. First they told us there were no space for carry on. It was plenty of space over our 2 row seats, we had to ask to let us travel with it which was accepted. They were aware that we had to run for the connection due to the previous flight delay. Have us one hour waiting for more customers and not even offer a glass of water. Then started the service and they started to serve other passengers drinks in business and did not offer any drinks until they serve our pre ordered meal and I ask for something to drink. I had to wait until they finished to serve all passengers until Inget something. The crew was the worts I ever had for Business Class in my life.

Very turbulent trip made it pretty bearable, plus the lack of refreshments served and the lack of any air conditioning before takeoff which took an hour or more.

Flight was late - I was downgraded from first class to coach

Not good - outbound flight was delayed and missed my connection even though I got to the gate after running through the airport - the agent would not let me on because the door was closed (flight had not left). There was no notification from United - overall experience was very disappointing. Additionally, I was downgraded from first class to coach on the alternative flight

The flight was on time. I generally don’t drink or eat on short flights and the seats were good and the flight attendants were friendly. That’s all I expect

It was nice to have gotten up upgraded to first class with a meal on a three hour flight

Not great experience - we were super late boarding due to issues with aircraft. Then when we finally all got onboard and seated and they started taxiing out to the runway they just stopped then turned around and went back to the airport. Apparently the crew “ran out of time” to legally fly us. They mentioned that they were about 2 minutes away from taking off. I understand the rules and safety but kinda wonder why they would have bothered boarding us in the first place? Had to go all the way back and de plane and then wait in a HUGE line to get a hotel (this is somewhere around 2:30am) finally got to hotel by Uber (no shuttle after 20min so gave up) and they ended up putting us all back on the same aircraft at 10am next morning so got about 2.5 hours sleep. They did give us. $250 credit, but it was a São Paulo Brazil flight out of Dulles. The flight and everything was fine.

United overall experience is great these days. Airport experience was very organized. Staff on flight were great. App and information as good as it gets.

United have really come back. Airport and boarding process is clear and good, app and information also very good

They charged a fee for 1st bag checked. Others in same party were free.

The boarding by groups is pointless. The first two groups worked fine, but almost Noone boarded in goups three thru five leaving the vast majority boarding when group six was called. It defeated the purpose of spreading out the crowd.

I don’t know who decides what food to serve on these flights but I would be so embarrassed if I served this to anyone and call it food…

For whatever reason, the flight was not catered -we were told it would be a 45 minute delay waiting for catering - so no food. There were opened candy and peanuts in the seatback pocket. Flight landed early in DFW but due to the assigned gate not being available, we sat on the ground for 30 minutes waiting for the gate to open - making the flight actually arrive at the gate late.

Not great. Booked Extra seats and got nothing extra at all. It’s basically a big budget airline.

The pilot greased the landing and the crew was fantastic.

I bought wifi and most of the flight could not even use it my apps would just spin. I couldn't even listen to music. super frustrating.

delayed due to weather. Could not communicate with family since the wifi was broken

Experience was good, however I had a delay due to weather happening and had to re purchase a seat on a new plane for a higher price (could be my own issue and misunderstanding) but other than that situation. First time flyer (by myself) was terrific!! The last from ORD to ALO didn't have wifi, but it was only 45 minutes so I'm sure that was part of the reason. Overall my experience was great! Next time I will remember to buy tickets with longer layovers. The delays really saved my overall anxiety. :)

Flight was delayed 17 hours due to aircraft issues. American did provide hotel, transportation and meals, 3 hours past boarding time, but it took us another hour to get the vouchers.

Flight was on time is the only good thing. Person loading the plane called 1-6 to board at the same time, made it chaotic. Plane was too small for even putting backpacks in overhead. Seat for normal sized people were too small. The WIFI didn't work. When we landed had to wait because not enough ground crew.

Not clean and was told I would get a great seat and it was not great at all

Flight got delayed for 5 hours no good explanation was offered ;(

Horrible. I would never fly Frontier again. The booking process is tricky at best, but fraudulent in my opinion. Frontier customer service did nothing to rectify my purchase -- I ended up paying more than double what I could have gotten from other airlines and nearly triple what I thought I was buying from Frontier. Their booking practices are unfair to the consumer.

Delayed. Text notifications were slow. Not much information o what was happening. Boarding was slow and confusing. Wasn’t even offered water other flight. Had to ask. No entertainment at all. Felt like.a Greyhound bus.

When I wanted to check in 3 hours prior to boarding time, the employees mentioned “a little over an hour delay” so I waited for an hour then I went to go look for food in the terminal and most people from that flight were in the same area looking for food. Finally I decided after food to check to see if it’s anytime closer and now it’s 2 mins until boarding closes?! What are you kidding me? I didn’t receive anything via sms about boarding now nor via email or on the intercom. I luckily made it through, barely, and then there’s no room for my carry on mind you I’m in the very first row so I had to place my purse in one further row back and my carry on sections down. Not sure who pays for better seats to get your stuff placed all over the plane but that was the worst experience I’ve ever had flying with anyone.

Better than expected. Staff were friendly and nice on both flights.

There was no one at the counter to assist with our check in. The app didn’t work, so I arrived at the airport with time to check in and I couldn’t because no employees were there. When I finally got someone on the phone, it was inside the 60min rule and they said I could no longer check in and they could sell me another ticket. We had to scramble and pay an additional $800 for tickets and THEN AFTER (about 60 min from my original convo with customer service and 10min after original departure time) I had boarded my new flight, there was email saying my original flight from Frontier was delayed and leaving 2hr 50min later, but I STILL wouldn’t have been able to check in. Which means customer service should have been able to see it and let me check in because I was well within my check in time. When I call Frontier, they hang up on me. So their app didn’t work and they employees left and they take zero responsibility or assistance with their “customer service”

Terrible. Flight cancelled with no reasoning and no flights to rebook. Employees were useless and did nothing to help. Did not even know where to retrieve luggage from the cancelled flight. Flyers beware.

No fault of Frontier staff: plane was very late, reached Orlando at 1 am, took a while to get luggage. Weather, gov financial shutdown impact on TSA, air controllers seemed to have multiple flights backed up. Frontier staff seemed to cope as gracefully as possible. It did reassure me that I and my new hip could adapt to travel challenges. Food/entertainment were irrelevant to my trip.

Terrible. The canceled my entire flight when I requested a refund for a trip frontier canceled trip one way.

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

Information on your arrival and departure airports