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Cheap flights from St. Louis to San Juan from $87

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to San Juan departing on 4/20. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
1 adult, Economy, 0 bags

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Find the cheapest flights from St. Louis to San Juan

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
4:51 pm - 2:03 am
STL
-
SJU
8h 12m
1 stop
Frontier Logo
9:10 pm - 7:51 am
SJU
-
STL
11h 41m
1 stop
$261Frontier
Fri, Mar 27 - Fri, Apr 3
Frontier Logo
4:59 pm - 2:01 am
STL
-
SJU
8h 02m
1 stop
Frontier Logo
3:08 am - 11:19 pm
SJU
-
STL
21h 11m
1 stop
$263Frontier
Mon, Apr 20 - Mon, Apr 27
Frontier Logo
4:59 pm - 10:39 am
STL
-
SJU
16h 40m
1 stop
Frontier Logo
6:00 am - 12:21 am
SJU
-
STL
19h 21m
1 stop
$266Frontier
Sat, May 2 - Sat, May 9
Frontier Logo
4:59 pm - 2:01 am
STL
-
SJU
8h 02m
1 stop
Frontier Logo
3:26 pm - 11:19 pm
SJU
-
STL
8h 53m
1 stop
$271Frontier
Tue, Apr 28 - Sat, May 2
Frontier Logo
4:59 pm - 2:01 am
STL
-
SJU
8h 02m
1 stop
Frontier Logo
3:19 pm - 11:19 pm
SJU
-
STL
9h 00m
1 stop
$281Frontier
Tue, Apr 7 - Wed, Apr 15
American Airlines Logo
6:29 am - 10:05 pm
STL
-
SJU
14h 36m
1 stop
American Airlines Logo
7:00 pm - 10:16 am
SJU
-
STL
16h 16m
1 stop
$282American Airlines
Sat, May 9 - Tue, May 12
Frontier Logo
4:54 pm - 2:01 am
STL
-
SJU
8h 07m
1 stop
Frontier Logo
11:01 am - 11:25 pm
SJU
-
STL
13h 24m
1 stop
$288Frontier
Wed, Apr 1 - Sun, Apr 5
Frontier Logo
4:59 pm - 9:54 am
STL
-
SJU
15h 55m
1 stop
Frontier Logo
3:39 pm - 11:19 pm
SJU
-
STL
8h 40m
1 stop
$292Frontier
Sun, Apr 26 - Thu, Apr 30
Frontier Logo
4:59 pm - 9:54 am
STL
-
SJU
15h 55m
1 stop
Frontier Logo
3:21 am - 11:19 pm
SJU
-
STL
20h 58m
1 stop
$293Frontier
Mon, Apr 20 - Sun, Apr 26
Frontier Logo
4:19 pm - 8:04 am
STL
-
SJU
14h 45m
1 stop
Frontier Logo
6:09 pm - 12:21 am
SJU
-
STL
7h 12m
1 stop
$294Frontier
Thu, May 14 - Sun, May 17

Frontier flights from St. Louis to San Juan Luis Munoz Marin Intl Airport

Our best Frontier deals on St. Louis to San Juan Luis Munoz Marin Intl Airport flight tickets
Frontier
Mar 27
STL4:51 pmLambert-St Louis
8h 12m
1 stop
SJU2:03 amSan Juan Luis Munoz Marin Intl
Apr 3
SJU9:10 pmSan Juan Luis Munoz Marin Intl
11h 41m
1 stop
STL7:51 amLambert-St Louis
$261
Frontier
Apr 20
STL4:59 pmLambert-St Louis
8h 02m
1 stop
SJU2:01 amSan Juan Luis Munoz Marin Intl
Apr 27
SJU3:08 amSan Juan Luis Munoz Marin Intl
21h 11m
1 stop
STL11:19 pmLambert-St Louis
$263
Frontier
May 2
STL4:59 pmLambert-St Louis
16h 40m
1 stop
SJU10:39 amSan Juan Luis Munoz Marin Intl
May 9
SJU6:00 amSan Juan Luis Munoz Marin Intl
19h 21m
1 stop
STL12:21 amLambert-St Louis
$266

American Airlines flights from St. Louis to San Juan Luis Munoz Marin Intl Airport

Our best American Airlines deals on St. Louis to San Juan Luis Munoz Marin Intl Airport flight tickets
American Airlines
May 9
STL6:29 amLambert-St Louis
14h 36m
1 stop
SJU10:05 pmSan Juan Luis Munoz Marin Intl
May 12
SJU7:00 pmSan Juan Luis Munoz Marin Intl
16h 16m
1 stop
STL10:16 amLambert-St Louis
$282
American Airlines
Apr 26
STL6:29 amLambert-St Louis
10h 41m
2 stops
SJU6:10 pmSan Juan Luis Munoz Marin Intl
Apr 30
SJU1:31 pmSan Juan Luis Munoz Marin Intl
11h 15m
2 stops
STL11:46 pmLambert-St Louis
$322
American Airlines
Apr 15
STL5:24 amLambert-St Louis
8h 28m
1 stop
SJU2:52 pmSan Juan Luis Munoz Marin Intl
Apr 21
SJU7:00 pmSan Juan Luis Munoz Marin Intl
16h 16m
1 stop
STL10:16 amLambert-St Louis
$327

momondo Fare Finder

 
Customize your flight search to find flights from St. Louis to San Juan Luis Munoz Marin Intl Airport 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, momondo users made 832,500 searches. Data last updated March 23, 2026.
Use the filters below to find and compare flights from St. Louis to San Juan Luis Munoz Marin Intl Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Fri 3/27

4:51 pm-2:03 am

1 stop8h 12m

San Juan Luis Munoz Marin Intl

Fri 4/3

9:10 pm-7:51 am

1 stop11h 41m

$261

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Mon 4/20

4:59 pm-2:01 am

1 stop8h 02m

San Juan Luis Munoz Marin Intl

Mon 4/27

3:08 am-11:19 pm

1 stop21h 11m

$263

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 5/2

4:59 pm-10:39 am

1 stop16h 40m

San Juan Luis Munoz Marin Intl

Sat 5/9

6:00 am-12:21 am

1 stop19h 21m

$266
Quickest round-trip

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Tue 4/28

4:59 pm-2:01 am

1 stop8h 02m

San Juan Luis Munoz Marin Intl

Sat 5/2

3:26 pm-11:19 pm

1 stop8h 53m

$271

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Tue 4/7

4:59 pm-2:01 am

1 stop8h 02m

San Juan Luis Munoz Marin Intl

Wed 4/15

3:19 pm-11:19 pm

1 stop9h 00m

$281

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 5/9

6:29 am-10:05 pm

1 stop14h 36m

San Juan Luis Munoz Marin Intl

Tue 5/12

7:00 pm-10:16 am

1 stop16h 16m

$282

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 4/1

4:54 pm-2:01 am

1 stop8h 07m

San Juan Luis Munoz Marin Intl

Sun 4/5

11:01 am-11:25 pm

1 stop13h 24m

$288

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sun 4/26

4:59 pm-9:54 am

1 stop15h 55m

San Juan Luis Munoz Marin Intl

Thu 4/30

3:39 pm-11:19 pm

1 stop8h 40m

$292

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Mon 4/20

4:59 pm-9:54 am

1 stop15h 55m

San Juan Luis Munoz Marin Intl

Sun 4/26

3:21 am-11:19 pm

1 stop20h 58m

$293

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Thu 5/14

4:19 pm-8:04 am

1 stop14h 45m

San Juan Luis Munoz Marin Intl

Sun 5/17

6:09 pm-12:21 am

1 stop7h 12m

$294

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to San Juan from

How to get the cheapest flight ticket from St. Louis to San Juan Luis Munoz Marin Intl Airport

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the typical price of a round-trip flight between St. Louis and San Juan Luis Munoz Marin Intl Airport?

What is the cheapest month to fly to San Juan Luis Munoz Marin Intl Airport?

If you aren’t able to travel to San Juan Luis Munoz Marin Intl Airport during the month of September, then flying in April is also cheap. Prices for this month can be found on momondo for an average of $345.

What is the cheapest Lambert-St Louis to San Juan Luis Munoz Marin Intl flight route?

Fly from Lambert-St Louis to San Juan Luis Munoz Marin Intl for the best Lambert-St Louis - San Juan Luis Munoz Marin Intl flight prices

How far in advance should I book a flight to San Juan Luis Munoz Marin Intl Airport?

You are more likely to see cheaper flights to San Juan Luis Munoz Marin Intl Airport from St. Louis when booking weeks ahead of your departure date. In general, you can expect to find flights to San Juan Luis Munoz Marin Intl Airport for around $426 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to San Juan Luis Munoz Marin Intl Airport from St. Louis for as low as $342 on momondo.

What cabin class options are available on Lambert-St Louis to San Juan Luis Munoz Marin Intl flights?

There is only 1 cabin class available to choose from on Lambert-St Louis to San Juan Luis Munoz Marin Intl flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

How have St. Louis to San Juan Luis Munoz Marin Intl Airport flight prices changed over time?

As of March 2026, prices for St. Louis to San Juan Luis Munoz Marin Intl Airport flights are approximately 2% cheaper when compared to flights at the same time last year.

When to book flights from St. Louis to San Juan Luis Munoz Marin Intl Airport

Are you open to changing your travel dates? Check out the ideal times to fly from St. Louis to San Juan Luis Munoz Marin Intl Airport according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap St. Louis to San Juan Luis Munoz Marin Intl Airport (STL to SJU) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from St. Louis to San Juan Luis Munoz Marin Intl Airport

Fastest flight time

6h 30m

Direct flights

Sun
The fastest flight from St. Louis to San Juan Luis Munoz Marin Intl Airport takes 6h 30m
Direct flights go from St. Louis to San Juan Luis Munoz Marin Intl Airport on Sunday. There are no airlines offering direct flights.
Search flight deals

  • How far is Lambert-St Louis to San Juan Luis Munoz Marin Intl by plane?

    There are 2011.8 mi between Lambert-St Louis and San Juan Luis Munoz Marin Intl. A reasonable flight in good conditions will take 6h 30m.

  • When did momondo last update prices for flights from Lambert-St Louis Airport to San Juan Luis Munoz Marin Intl Airport?

    Prices for flights from Lambert-St Louis Airport to San Juan Luis Munoz Marin Intl Airport are updated daily.

  • How many operators does momondo search for flights from Lambert-St Louis Airport to San Juan Luis Munoz Marin Intl Airport?

  • How old do you have to be to fly from Lambert-St Louis Airport to San Juan Luis Munoz Marin Intl Airport?

    The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Lambert-St Louis Airport to San Juan Luis Munoz Marin Intl Airport.

  • What documentation or ID do you need to fly to San Juan Luis Munoz Marin Intl Airport?

    The travel and health documents you'll need for your trip to San Juan Luis Munoz Marin Intl Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at San Juan Luis Munoz Marin Intl Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

  • What is the most popular plane model from St. Louis to San Juan Luis Munoz Marin Intl Airport?

  • What is the most popular airline from St. Louis to San Juan Luis Munoz Marin Intl Airport?

Best airlines flying from St. Louis to San Juan Luis Munoz Marin Intl Airport

Compare and see reviews for airlines that fly from St. Louis to San Juan Luis Munoz Marin Intl Airport with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $138Free CancellationRating
5.7
3,020 reviews
Search Frontier flights
Spirit AirlinesPriceFrom $146Free CancellationRating
6.3
8,538 reviews
Search Spirit Airlines flights
DeltaPriceFrom $197Free CancellationRating
7.9
8,317 reviews
Search Delta flights
SouthwestPriceFrom $219Free CancellationRating
8.0
4,324 reviews
Search Southwest flights
United AirlinesPriceFrom $225Free CancellationRating
7.4
9,462 reviews
Search United Airlines flights
American AirlinesPriceFrom $228Free CancellationRating
7.1
11,486 reviews
Search American Airlines flights

  • Southwest Flights From St. Louis to San Juan Luis Munoz Marin Intl Airport

    Southwest operates around 1 flight from St. Louis to San Juan Luis Munoz Marin Intl Airport every week. The average price of these flights found in the last 72 hours has been $516, but momondo users have found Southwest deals from St. Louis to San Juan Luis Munoz Marin Intl Airport from as low as $219 round-trip. Southwest has been scored 8.0/10 in 4,324 reviews.

Traveling to a place near San Juan?

Book flights to San Juan if you plan to visit one of these locations
Carolina
Fajardo
Dorado
Luquillo
Caguas
Rio Grande
Humacao
Bayamón

Why use momondo?

Why should I use momondo to find a flight deal from St. Louis to San Juan?

momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from St. Louis to San Juan. Millions of users trust and use momondo every year so you are in good hands.

Can I find flights from St. Louis to San Juan with flexible booking policies on momondo?

All flight searches from St. Louis to San Juan on momondo can be filtered to show those which offer flexible booking policies.

How can momondo help me find flights from St. Louis to San Juan?

Once you have performed a search in the form on the page, momondo provides useful filters and insights. We can show you the cheapest days and times to fly as well as help filter your options to help you make an informed choice when booking flights to San Juan from St. Louis.

I’m not ready to book a flight from St. Louis to San Juan right now. Can momondo alert me if prices change?

Yes momondo offers price alerts on flights to San Juan from St. Louis. After performing a search on this page you should be able to see the price alert set up feature. Simply provide a valid email address and momondo will instantly alert you when prices change.

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