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Cheap flights from St. Louis to San Juan from $141

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 8/21. 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

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from St. Louis to San Juan

Cheap round-trip flights

Enter your travel dates to find the best prices.
Southwest Logo
10:55 am - 5:15 pm
STL
-
SJU
4h 20mnonstop
Southwest Logo
10:55 am - 1:55 pm
SJU
-
STL
5h 00mnonstop
$327Southwest
Sat, Nov 7 - Sat, Nov 14
Southwest Logo
5:45 am - 3:00 pm
STL
-
SJU
7h 15m
1 stop
Southwest Logo
10:55 am - 1:55 pm
SJU
-
STL
5h 00mnonstop
$332Southwest
Sat, Nov 7 - Sat, Nov 14
Delta Logo
12:52 pm - 10:29 pm
STL
-
SJU
8h 37m
1 stop
Delta Logo
7:00 am - 2:33 pm
SJU
-
STL
8h 33m
1 stop
$336Delta
Fri, Aug 21 - Tue, Aug 25
American Airlines Logo
10:44 am - 9:55 pm
STL
-
SJU
10h 11m
2 stops
American Airlines Logo
2:22 pm - 9:55 pm
SJU
-
STL
8h 33m
1 stop
$341American Airlines
Wed, Sep 2 - Wed, Sep 9
American Airlines Logo
3:25 pm - 11:59 pm
STL
-
SJU
7h 34m
1 stop
American Airlines Logo
7:30 am - 4:50 pm
SJU
-
STL
10h 20m
1 stop
$346American Airlines
Thu, Sep 3 - Tue, Sep 8
Frontier Logo
10:35 am - 11:38 pm
STL
-
SJU
12h 03m
2 stops
Frontier Logo
3:51 pm - 9:40 am
SJU
-
STL
18h 49m
1 stop
$356Frontier
Sun, Oct 4 - Fri, Oct 9
United Airlines Logo
6:15 am - 3:42 pm
STL
-
SJU
8h 27m
1 stop
United Airlines Logo
7:10 am - 2:18 pm
SJU
-
STL
8h 08m
1 stop
$359United Airlines
Fri, Oct 23 - Sat, Oct 31
Frontier Logo
4:57 pm - 12:41 am
STL
-
SJU
30h 44m
2 stops
Frontier Logo
5:15 pm - 8:57 am
SJU
-
STL
16h 42m
1 stop
$361Frontier
Wed, Aug 5 - Sun, Aug 9
Frontier Logo
4:57 pm - 12:41 am
STL
-
SJU
30h 44m
2 stops
Frontier Logo
5:15 pm - 8:57 am
SJU
-
STL
16h 42m
1 stop
$362Frontier
Fri, Jul 17 - Tue, Jul 21
Southwest Logo
12:35 pm - 9:55 pm
STL
-
SJU
7h 20m
1 stop
Southwest Logo
10:55 am - 1:55 pm
SJU
-
STL
5h 00mnonstop
$363Southwest
Wed, Nov 11 - Sat, Nov 14

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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
Jul 28
STL3:41 pmLambert-St Louis
12h 21m
1 stop
SJU5:02 amSan Juan Luis Munoz Marin Intl
Aug 4
SJU6:45 amSan Juan Luis Munoz Marin Intl
27h 12m
2 stops
STL8:57 amLambert-St Louis
$359
Frontier
Aug 5
STL4:57 pmLambert-St Louis
30h 44m
2 stops
SJU12:41 amSan Juan Luis Munoz Marin Intl
Aug 9
SJU5:15 pmSan Juan Luis Munoz Marin Intl
16h 42m
1 stop
STL8:57 amLambert-St Louis
$361
Frontier
Jul 17
STL4:57 pmLambert-St Louis
30h 44m
2 stops
SJU12:41 amSan Juan Luis Munoz Marin Intl
Jul 21
SJU5:15 pmSan Juan Luis Munoz Marin Intl
16h 42m
1 stop
STL8:57 amLambert-St Louis
$362

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

Our best Southwest deals on St. Louis to San Juan Luis Munoz Marin Intl Airport flight tickets
Southwest
Aug 14
STL10:10 amLambert-St Louis
8h 55m
1 stop
SJU8:05 pmSan Juan Luis Munoz Marin Intl
Aug 17
SJU6:30 amSan Juan Luis Munoz Marin Intl
9h 25m
1 stop
STL2:55 pmLambert-St Louis
$381
Southwest
Aug 21
STL11:40 amLambert-St Louis
9h 30m
2 stops
SJU10:10 pmSan Juan Luis Munoz Marin Intl
Aug 26
SJU8:20 amSan Juan Luis Munoz Marin Intl
9h 25m
2 stops
STL4:45 pmLambert-St Louis
$398
Southwest
Aug 3
STL10:05 amLambert-St Louis
12h 35m
1 stop
SJU11:40 pmSan Juan Luis Munoz Marin Intl
Aug 7
SJU8:55 pmSan Juan Luis Munoz Marin Intl
11h 45m
1 stop
STL7:40 amLambert-St Louis
$400

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 June 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
Quickest round-trip

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 11/7

10:55 am-5:15 pm

Nonstop4h 20m

San Juan Luis Munoz Marin Intl

Sat 11/14

10:55 am-1:55 pm

Nonstop5h 00m

$327

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 11/7

5:45 am-3:00 pm

1 stop7h 15m

San Juan Luis Munoz Marin Intl

Sat 11/14

10:55 am-1:55 pm

Nonstop5h 00m

$332

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Fri 8/21

12:52 pm-10:29 pm

1 stop8h 37m

San Juan Luis Munoz Marin Intl

Tue 8/25

7:00 am-2:33 pm

1 stop8h 33m

$336

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 9/2

10:44 am-9:55 pm

2 stops10h 11m

San Juan Luis Munoz Marin Intl

Wed 9/9

2:22 pm-9:55 pm

1 stop8h 33m

$341

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Thu 9/3

3:25 pm-11:59 pm

1 stop7h 34m

San Juan Luis Munoz Marin Intl

Tue 9/8

7:30 am-4:50 pm

1 stop10h 20m

$346

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sun 10/4

10:35 am-11:38 pm

2 stops12h 03m

San Juan Luis Munoz Marin Intl

Fri 10/9

3:51 pm-9:40 am

1 stop18h 49m

$356

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Fri 10/23

6:15 am-3:42 pm

1 stop8h 27m

San Juan Luis Munoz Marin Intl

Sat 10/31

7:10 am-2:18 pm

1 stop8h 08m

$359

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 8/5

4:57 pm-12:41 am

2 stops30h 44m

San Juan Luis Munoz Marin Intl

Sun 8/9

5:15 pm-8:57 am

1 stop16h 42m

$361

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Fri 7/17

4:57 pm-12:41 am

2 stops30h 44m

San Juan Luis Munoz Marin Intl

Tue 7/21

5:15 pm-8:57 am

1 stop16h 42m

$362

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 11/11

12:35 pm-9:55 pm

1 stop7h 20m

San Juan Luis Munoz Marin Intl

Sat 11/14

10:55 am-1:55 pm

Nonstop5h 00m

$363

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 October is also cheap. Prices for this month can be found on momondo for an average of $325.

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 from St. Louis 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 $420 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 $348 on momondo.

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

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

Can stopping save me money on St. Louis to San Juan Luis Munoz Marin Intl Airport flights?

You could potentially save up to 2% on your flight if you consider stops on a St. Louis to San Juan Luis Munoz Marin Intl Airport flight.

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

As of June 2026, prices for St. Louis to San Juan Luis Munoz Marin Intl Airport flights are approximately 3% 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

4h 20m

Direct flights

Sun
The fastest flight from St. Louis to San Juan Luis Munoz Marin Intl Airport takes 4h 20m
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

Frequently asked questions about flying from St. Louis to San Juan Luis Munoz Marin Intl Airport

  • 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 4h 20m.

  • 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
5.6
2,871 reviews
Search Frontier flights
DeltaPriceFrom $205Free CancellationRating
7.8
8,421 reviews
Search Delta flights
United AirlinesPriceFrom $225Free CancellationRating
7.4
9,875 reviews
Search United Airlines flights
SouthwestPriceFrom $246Free CancellationRating
7.9
4,243 reviews
Search Southwest flights
American AirlinesPriceFrom $250Free CancellationRating
7.1
11,739 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 $487, but momondo users have found Southwest deals from St. Louis to San Juan Luis Munoz Marin Intl Airport from as low as $246 round-trip. Southwest has been scored 7.9/10 in 4,243 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
Humacao
Rio Grande
Caguas
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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