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$103+ 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
Aug 5 — Aug 121
Tue 8/5
Tue 8/12
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 71 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 July 31, 2025.

Round-trip from

$205
(Southwest)

One-way from

$103
(American Airlines)

Popular in

December

Cheapest in

September

Average price

$545
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. 6% potential increase in price ($32 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($13 potential savings vs. average RT price).
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Average for round-trip flights in July 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 July 31, 2025.

This Southwest deal was found by Cheapflights users on 7/29. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/213:25 pmSTL - SJU
1 stop7h 25mSouthwest
Sat 10/255:45 amSJU - STL
1 stop12h 20mSouthwest
Deal found 7/29$205
This Delta deal was found by Cheapflights users on 7/30. 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.
Mon 9/151:26 pmSTL - SJU
1 stop7h 34mDelta
Fri 9/1912:58 pmSJU - STL
1 stop11h 26mDelta
Deal found 7/30$215
This Priceline deal was found by Cheapflights users on 7/31. 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.
Sat 11/12:22 pmSTL - SJU
1 stop17h 37mFrontier
Fri 11/73:59 amSJU - STL
1 stop11h 28mFrontier
Deal found 7/31$239
This CheapOair deal was found by Cheapflights users on 7/29. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/191:57 pmSTL - SJU
1 stop11h 37mMultiple Airlines
Wed 9/241:59 amSJU - STL
2 stops9h 51mMultiple Airlines
Deal found 7/29$247
This Cheapflightsfares deal was found by Cheapflights users on 7/29. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/242:30 pmSTL - SJU
2 stops9h 26mSpirit Airlines
Thu 8/282:11 amSJU - STL
2 stops12h 21mSpirit Airlines
Deal found 7/29$249
This United Airlines deal was found by Cheapflights users on 7/30. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/206:15 amSTL - SJU
1 stop8h 27mUnited Airlines
Sat 10/251:30 pmSJU - STL
2 stops10h 05mUnited Airlines
Deal found 7/30$286
This American Airlines deal was found by Cheapflights users on 7/29. 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.
Fri 8/226:00 amSTL - SJU
1 stop15h 49mAmerican Airlines
Sat 8/306:00 amSJU - STL
2 stops11h 14mAmerican Airlines
Deal found 7/29$300

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 July 31, 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

Tue 10/21

3:25 pm-11:50 pm

1 stop7h 25m

San Juan Luis Munoz Marin Intl

Sat 10/25

5:45 am-5:05 pm

1 stop12h 20m

$205

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Mon 9/15

1:26 pm-10:00 pm

1 stop7h 34m

San Juan Luis Munoz Marin Intl

Fri 9/19

12:58 pm-11:24 pm

1 stop11h 26m

$215

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 8/13

5:40 pm-9:04 am

1 stop14h 24m

San Juan Luis Munoz Marin Intl

Sat 8/16

9:30 pm-11:47 pm

1 stop27h 17m

$239

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Fri 9/19

1:57 pm-2:34 am

1 stop11h 37m

San Juan Luis Munoz Marin Intl

Wed 9/24

1:59 am-10:50 am

2 stops9h 51m

$247

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sun 8/24

2:30 pm-12:56 am

2 stops9h 26m

San Juan Luis Munoz Marin Intl

Thu 8/28

2:11 am-1:32 pm

2 stops12h 21m

$249

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 9/20

6:15 am-3:42 pm

1 stop8h 27m

San Juan Luis Munoz Marin Intl

Sat 10/25

1:30 pm-10:35 pm

2 stops10h 05m

$286

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Fri 8/22

6:00 am-10:49 pm

1 stop15h 49m

San Juan Luis Munoz Marin Intl

Fri 8/29

12:00 pm-9:02 pm

2 stops10h 02m

$300

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 10/25

12:25 pm-11:57 pm

2 stops10h 32m

$103

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sun 8/31

10:20 am-10:07 pm

1 stop10h 47m

$108

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 8/13

5:40 pm-2:39 am

1 stop7h 59m

$119

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/29

Showing 1-10 of 13 results
1
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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 July 25, 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 71 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 July 31, 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.

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 July 31, 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
4,246 reviews

Comfort

8.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Overall

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.
Southwest
8.0
Very good
4,246 reviews
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Overall

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.
Delta
8.0
Very good
7,981 reviews
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Overall

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.
United Airlines
7.4
Good
8,900 reviews
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Overall

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Overall

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.
Spirit Airlines
6.3
Okay
8,049 reviews
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Boarding

8.1

Crew

8.6

Entertainment

7.5

Overall

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.

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.

  • 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 Southwest. Our recent data shows that you can find tickets from as low as $205 on this airline. Additional options worth looking into are Delta and Frontier, starting at $215 and $239 round-trip. Southwest is 54% 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 American Airlines, which is currently one of the cheapest options available, starting at $103. Delta flights start at $108 while deals on Frontier start at $119 one-way.

  • 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

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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 July 31, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$140Average$259FlexibilityNo cancel feeOn-time62%
Spirit AirlinesCheapest$155Average$319FlexibilityNo cancel feeOn-time65%
DeltaCheapest$218Average$392FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$219Average$381FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$219Average$593FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$255Average$497FlexibilityNo cancel feeOn-time71%

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