HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
San Juan

Cheap flights from St. Louis (STL) to San Juan

STL — SJU
Oct 28 — Nov 41
Wed 10/28
Wed 11/4
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from St. Louis to San Juan with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Find flight deals from St. Louis to San Juan

Popular in

December

Cheapest in

April

Average price

$336
Highest demand for flights based on searches. 16% potential increase in price ($88 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($13 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in September 2026
Search Deals

Best time to book a flight from St. Louis to San Juan

Have a flexible travel schedule? Discover the best time to fly to San Juan from St. Louis with our price prediction graph.
Estimated round-trip price

Cheapflights Insights

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

How far ahead should I book a flight from St. Louis to San Juan?

The price you pay for your flight from St. Louis to San Juan may vary depending on when you book. For the best chance of a lower fare, look to book 54 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

What is the cheapest month to book a flight from St. Louis to San Juan?

Currently, April is the cheapest month in which you can book a flight from St. Louis to San Juan (average of $334). Flying from St. Louis to San Juan in December is currently the most expensive (average of $577). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

Reviews of airlines servicing San Juan

Peruse reviews from past customers who have flown with Southwest,Delta, andUnited Airlines from St. Louis to San Juan to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,200 reviews

Overall

8.0

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Edward,Sep 2026

MCO - BWI

Changed flight which was easy. Gate Agent booked me from extra leg room seat on original flight to row 15 on new flight that did not have extra leg room - even though it was an exit row. The row in front of me with extra leg room had an empty seat.
Southwest
8.0
Very good
4,200 reviews
Southwest
8.0
Very good
4,200 reviews

Overall

8.0

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Edward,Sep 2026

MCO - BWI

Changed flight which was easy. Gate Agent booked me from extra leg room seat on original flight to row 15 on new flight that did not have extra leg room - even though it was an exit row. The row in front of me with extra leg room had an empty seat.
Delta
7.8
Good
8,606 reviews
Southwest
8.0
Very good
4,200 reviews

Overall

8.0

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Edward,Sep 2026

MCO - BWI

Changed flight which was easy. Gate Agent booked me from extra leg room seat on original flight to row 15 on new flight that did not have extra leg room - even though it was an exit row. The row in front of me with extra leg room had an empty seat.
United Airlines
7.4
Good
10,247 reviews
Southwest
8.0
Very good
4,200 reviews

Overall

8.0

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Edward,Sep 2026

MCO - BWI

Changed flight which was easy. Gate Agent booked me from extra leg room seat on original flight to row 15 on new flight that did not have extra leg room - even though it was an exit row. The row in front of me with extra leg room had an empty seat.
American Airlines
7.0
Good
12,098 reviews
Southwest
8.0
Very good
4,200 reviews

Overall

8.0

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Edward,Sep 2026

MCO - BWI

Changed flight which was easy. Gate Agent booked me from extra leg room seat on original flight to row 15 on new flight that did not have extra leg room - even though it was an exit row. The row in front of me with extra leg room had an empty seat.
Frontier
5.6
Fair
2,572 reviews
Southwest
8.0
Very good
4,200 reviews

Overall

8.0

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Edward,Sep 2026

MCO - BWI

Changed flight which was easy. Gate Agent booked me from extra leg room seat on original flight to row 15 on new flight that did not have extra leg room - even though it was an exit row. The row in front of me with extra leg room had an empty seat.

Related info for your journey

  • What airport do you fly from for flights from St. Louis to San Juan?

    Most people fly from Lambert-St Louis (STL) if they book a flight from St. Louis to San Juan. On average, Lambert-St Louis has 0 outbound flights to San Juan per day from 6 airlines. Lambert-St Louis is conveniently located just 12.7 mi from St. Louis’s city center.

  • What are the cheapest airlines flying from St. Louis to San Juan round-trip?

    Our cheapest airline available from St. Louis to San Juan is Frontier. Our recent data shows that you can find tickets from as low as $148 on this airline. Additional options worth looking into are United Airlines and Delta, starting at $225 and $225 round-trip. Frontier is 65% cheaper than the average price of flights available within the next 90 days to this destination.

  • What are the cheapest airlines to fly from St. Louis to San Juan one-way?

    To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $98. United Airlines flights start at $112 while deals on Delta start at $128 one-way.

  • What are the cheapest flights from St. Louis to San Juan?

    The cheapest flight price from St. Louis to San Juan is $572. On average you can expect to pay $572. The most popular route, (Lambert-St Louis - San Juan Luis Munoz Marin Intl), can usually be booked for $346.

  • Can I find deals for flights from St. Louis to San Juan that include hotel bookings?

    Yes. In addition to deals on St. Louis to San Juan flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from St. Louis to San Juan?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to San Juan.

  • Can I find deals for business class flights from St. Louis to San Juan?

    Yes. Cheapflights offers flight deals from St. Louis to San Juan by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from St. Louis to San Juan?

    Currently, April is the cheapest month in which you can book a flight from St. Louis to San Juan (average of $334). Flying from St. Louis to San Juan in December is currently the most expensive (average of $577). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for St. Louis to San Juan

Kansas City to Luis Munoz Marin Intl flights
St. Louis to Luis Munoz Marin Intl flights
Springfield to Luis Munoz Marin Intl flights
Kansas City to Aguadilla flights

Top 6 airlines flying from St. Louis to San Juan

AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$148Average$332FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$225Average$406FlexibilityNo cancel feeOn-time69%
DeltaCheapest$225Average$463FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$246Average$445FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$334Average$509FlexibilityNo cancel feeOn-time63%
JetBlueCheapest$381Average$572FlexibilityNo cancel feeOn-time62%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.