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San Juan

$113+ Cheap flights from St. Louis (STL) to San Juan

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 10/25. Fares are subject to change and may not be available on all flights or dates of travel.
STL — SJU
Oct 16 — Oct 231
Thu 10/16
Thu 10/23
1 adult, Economy
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Cheapflights Tip: The best prices from Lambert-St Louis to San Juan are usually found in September or April, booked 23 days in advance, depart on a Wednesday or Tuesday and return on a Tuesday

Cheap flight deals from St. Louis to San Juan

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to San Juan (PR1). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated September 16, 2025.

Round-trip from

$225
(American Airlines)

One-way from

$113
(Delta)

Popular in

December

Cheapest in

September

Average price

$291
From Lambert-St Louis to San Juan
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One-way flight from Lambert-St Louis to San Juan
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Highest demand for flights based on searches. 10% potential increase in price ($51 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($15 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Find flight deals from St. Louis to San Juan

Cheapest flights from St. Louis to San Juan
Explore the most affordable flight options available from St. Louis to San Juan. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 16, 2025.

This American Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/186:00 amSTL - SJU
1 stop16h 05mAmerican Airlines
Wed 10/223:00 pmSJU - STL
1 stop9h 54mAmerican Airlines
Deal found 9/14$225
This American Airlines deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/158:30 amSTL - SJU
1 stop12h 40mAmerican Airlines
Wed 10/223:00 pmSJU - STL
1 stop9h 54mAmerican Airlines
Deal found 9/15$231
This Frontier deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/274:13 pmSTL - SJU
1 stop8h 41mFrontier
Thu 12/43:55 amSJU - STL
1 stop6h 50mFrontier
Deal found 9/14$268
This Delta deal was found by Cheapflights users on 9/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/911:40 amSTL - SJU
1 stop9h 30mDelta
Fri 12/123:20 pmSJU - STL
1 stop7h 26mDelta
Deal found 9/16$269
This Priceline deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/291:57 pmSTL - SJU
1 stop29h 34mFrontier
Thu 10/24:42 pmSJU - STL
1 stop28h 55mFrontier
Deal found 9/14$272
This Priceline deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/246:42 pmSTL - SJU
1 stop16h 18mFrontier
Sun 10/263:40 amSJU - STL
1 stop14h 30mFrontier
Deal found 9/14$276
This Frontier deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/114:33 pmSTL - SJU
1 stop8h 57mFrontier
Sat 10/183:40 amSJU - STL
1 stop10h 06mFrontier
Deal found 9/14$286
This Priceline deal was found by Cheapflights users on 9/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/106:05 pmSTL - SJU
1 stop7h 25mFrontier
Fri 10/179:19 pmSJU - STL
1 stop19h 19mFrontier
Deal found 9/16$290
This American Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/186:00 amSTL - SJU
1 stop16h 05mAmerican Airlines
Tue 10/217:00 amSJU - STL
2 stops12h 46mAmerican Airlines
Deal found 9/14$298
This Priceline deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/51:57 pmSTL - SJU
1 stop11h 37mFrontier
Sat 10/112:17 pmSJU - STL
1 stop23h 29mFrontier
Deal found 9/15$304
This Kiwi.com deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/2810:35 amSTL - SJU
1 stop23h 29mMultiple Airlines
Wed 10/14:51 pmSJU - STL
2 stops23h 13mMultiple Airlines
Deal found 9/14$312

Cheapflights Fare Finder

 
Customize your flight search to find flights from St. Louis to San Juan that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated September 16, 2025.
Use the filters below to find and compare flights from St. Louis to San Juan that are best for you.

Fly from

St. Louis

Fly to

San Juan

Route

Depart

Return

Price

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Fri 10/24

1:55 pm-12:45 am

1 stop9h 50m

San Juan Luis Munoz Marin Intl

Tue 10/28

6:10 am-8:00 pm

2 stops14h 50m

$225

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Tue 3/3

6:00 am-2:15 pm

1 stop6h 15m

San Juan Luis Munoz Marin Intl

Wed 3/4

6:17 pm-11:40 pm

1 stop7h 23m

$269

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sun 2/22

7:30 am-8:30 pm

1 stop11h 00m

San Juan Luis Munoz Marin Intl

Sat 2/28

6:15 am-3:01 pm

1 stop10h 46m

$269

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 10/29

8:55 am-10:45 pm

2 stops12h 50m

San Juan Luis Munoz Marin Intl

Sun 11/2

5:40 am-10:20 am

1 stop6h 40m

$298

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 10/18

9:20 am-11:57 pm

2 stops13h 37m

San Juan Luis Munoz Marin Intl

Tue 10/21

1:05 am-10:49 am

2 stops10h 44m

$334

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Fri 2/6

1:40 pm-12:40 am

2 stops9h 00m

San Juan Luis Munoz Marin Intl

Mon 2/9

6:10 am-4:40 pm

1 stop12h 30m

$400

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 11/1

6:43 pm-9:00 pm

1 stop25h 17m

San Juan Luis Munoz Marin Intl

Fri 1/30

2:05 am-10:41 am

1 stop10h 36m

$429

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sun 2/22

5:00 am-4:55 pm

2 stops9h 55m

San Juan Luis Munoz Marin Intl

Sat 2/28

6:05 am-3:15 pm

2 stops11h 10m

$433

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 10/29

10:00 am-8:00 pm

1 stop9h 00m

San Juan Luis Munoz Marin Intl

Sat 11/1

2:05 am-11:41 am

1 stop10h 36m

$438

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Fri 11/7

3:45 pm-12:35 am

1 stop6h 50m

San Juan Luis Munoz Marin Intl

Sat 11/15

8:50 am-12:00 pm

Nonstop5h 10m

$450

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/15

Showing 1-10 of 20 results
1
2

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
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

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?

Use this chart to determine the optimal time to book a round-trip flight from St. Louis to San Juan. Price data was last updated on September 12, 2025.

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 23 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, September is the cheapest month in which you can book a flight from St. Louis to San Juan (average of $254). Flying from St. Louis to San Juan in June is currently the most expensive (average of $339). 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.

What is the cheapest time of day to fly from STL to SJU?

Find hourly flight availability from St. Louis to San Juan. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 16, 2025.

When flying from St. Louis to San Juan, the time of day you fly usually plays a role in the price. Save by searching for a flight in the evening, which can drop the price by up to 53% versus a flight at noon.

What is the cheapest day to fly from St. Louis to San Juan?

Use this chart to determine the cheapest time to fly round-trip from St. Louis to San Juan. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their St. Louis to San Juan flight should consider departing on Tuesday evenings when fares are most often at their lowest. Saturday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

How much does it cost to fly round-trip from St. Louis to San Juan?

Reviews of airlines servicing San Juan

Get insights into the airlines that provide service to San Juan. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to San Juan. Reviews last updated September 16, 2025.
Peruse reviews from past customers who have flown with Southwest, Delta, and United 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
4,242 reviews

Boarding

8.1

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Southwest
8.0
Very good
4,242 reviews
Southwest
8.0
Very good
4,242 reviews

Boarding

8.1

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Delta
8.0
Very good
7,957 reviews
Southwest
8.0
Very good
4,242 reviews

Boarding

8.1

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
United Airlines
7.4
Good
8,924 reviews
Southwest
8.0
Very good
4,242 reviews

Boarding

8.1

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,242 reviews

Boarding

8.1

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Frontier
5.8
Fair
3,174 reviews
Southwest
8.0
Very good
4,242 reviews

Boarding

8.1

Overall

8.0

Crew

8.6

Entertainment

7.5

Food

7.0

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

Related info for your journey

Find useful and relevant information for your journey from St. Louis to San Juan. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • 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.

  • How long is the flight from St. Louis to San Juan?

    For as low as $269, Southwest can have you in San Juan from St. Louis in 6h 15m. The distance between St. Louis and San Juan is about 2024 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • 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 $140 on this airline. Additional options worth looking into are Spirit Airlines and Delta, starting at $170 and $209 round-trip. Frontier is 68% cheaper than the average price of flights available within the next 90 days to this destination.

  • 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, September is the cheapest month in which you can book a flight from St. Louis to San Juan (average of $254). Flying from St. Louis to San Juan in June is currently the most expensive (average of $339). 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

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Alternative routes for St. Louis to San Juan

See prices for flight routes from nearby airports that may be better suited for you.
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
St. Louis to Culebra flights

Top 6 airlines flying from St. Louis to San Juan

Discover the top 6 airlines that operate flights from St. Louis to San Juan. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated September 16, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$140Average$270FlexibilityNo cancel feeOn-time62%
Spirit AirlinesCheapest$170Average$329FlexibilityNo cancel feeOn-time65%
DeltaCheapest$209Average$378FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$219Average$379FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$219Average$594FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$255Average$524FlexibilityNo cancel feeOn-time71%

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