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Cheap flights from St. Louis to San Juan from $90

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 1/8. 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
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
12:12 pm - 11:59 pm
STL
-
SJU
9h 47m1 stop
Frontier Logo
4:36 pm - 11:33 pm
SJU
-
STL
8h 57m1 stop
$180Frontier
Sat, Jan 24 - Tue, Jan 27
Frontier Logo
5:42 pm - 11:59 pm
STL
-
SJU
28h 17m1 stop
Frontier Logo
8:00 am - 11:33 pm
SJU
-
STL
17h 33m1 stop
$181Frontier
Wed, Jan 21 - Mon, Jan 26
Frontier Logo
10:16 am - 6:40 pm
STL
-
SJU
6h 24m1 stop
Frontier Logo
4:36 pm - 11:33 pm
SJU
-
STL
8h 57m1 stop
$201Frontier
Mon, Jan 26 - Thu, Jan 29
Frontier Logo
11:18 am - 11:59 pm
STL
-
SJU
10h 41m1 stop
Frontier Logo
4:36 pm - 11:33 pm
SJU
-
STL
8h 57m1 stop
$215Frontier
Fri, Jan 23 - Mon, Jan 26
Frontier Logo
12:12 pm - 9:54 am
STL
-
SJU
19h 42m1 stop
Frontier Logo
6:00 am - 9:21 am
SJU
-
STL
29h 21m1 stop
$216Frontier
Sat, Jan 31 - Sun, Feb 8
Frontier Logo
12:12 pm - 11:59 pm
STL
-
SJU
9h 47m1 stop
Frontier Logo
4:36 pm - 11:33 pm
SJU
-
STL
8h 57m1 stop
$222Frontier
Sat, Jan 24 - Sat, Jan 31
Delta Logo
1:30 pm - 10:54 pm
STL
-
SJU
8h 24m1 stop
Delta Logo
6:15 am - 12:54 pm
SJU
-
STL
7h 39m1 stop
$225Delta
Sat, May 2 - Sat, May 9
Frontier Logo
5:42 pm - 10:24 am
STL
-
SJU
14h 42m1 stop
Frontier Logo
5:39 pm - 9:21 am
SJU
-
STL
17h 42m1 stop
$228Frontier
Thu, Jan 29 - Sun, Feb 1
Multiple Airlines Logo
5:42 pm - 11:59 pm
STL
-
SJU
28h 17m1 stop
Multiple Airlines Logo
4:40 pm - 11:33 pm
SJU
-
STL
32h 53m2 stops
$231Multiple Airlines
Wed, Jan 21 - Wed, Jan 28
Frontier Logo
5:42 pm - 11:59 pm
STL
-
SJU
28h 17m1 stop
Frontier Logo
8:00 am - 9:21 am
SJU
-
STL
27h 21m1 stop
$235Frontier
Wed, Jan 21 - Sun, Jan 25

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
Jan 24
STL12:12 pmLambert-St Louis
9h 47m
1 stop
SJU11:59 pmSan Juan Luis Munoz Marin Intl
Jan 27
SJU4:36 pmSan Juan Luis Munoz Marin Intl
8h 57m
1 stop
STL11:33 pmLambert-St Louis
$180
Find similar
Frontier
Jan 21
STL5:42 pmLambert-St Louis
28h 17m
1 stop
SJU11:59 pmSan Juan Luis Munoz Marin Intl
Jan 26
SJU8:00 amSan Juan Luis Munoz Marin Intl
17h 33m
1 stop
STL11:33 pmLambert-St Louis
$181
Find similar
Frontier
Jan 26
STL10:16 amLambert-St Louis
6h 24m
1 stop
SJU6:40 pmSan Juan Luis Munoz Marin Intl
Jan 28
SJU4:36 pmSan Juan Luis Munoz Marin Intl
8h 57m
1 stop
STL11:33 pmLambert-St Louis
$201
Find similar

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
Feb 5
STL6:00 amLambert-St Louis
15h 56m
1 stop
SJU11:56 pmSan Juan Luis Munoz Marin Intl
Feb 9
SJU7:12 pmSan Juan Luis Munoz Marin Intl
15h 56m
1 stop
STL9:08 amLambert-St Louis
$273
Find similar
American Airlines
Dec 16
STL10:13 amLambert-St Louis
9h 56m
1 stop
SJU10:09 pmSan Juan Luis Munoz Marin Intl
Jan 15
SJU4:49 pmSan Juan Luis Munoz Marin Intl
9h 10m
1 stop
STL11:59 pmLambert-St Louis
$408
Find similar
American Airlines
Dec 16
STL6:00 amLambert-St Louis
15h 52m
1 stop
SJU11:52 pmSan Juan Luis Munoz Marin Intl
Jan 15
SJU4:49 pmSan Juan Luis Munoz Marin Intl
9h 10m
1 stop
STL11:59 pmLambert-St Louis
$410
Find similar

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 December 4, 2025.
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

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 1/24

12:12 pm-11:59 pm

1 stop9h 47m

San Juan Luis Munoz Marin Intl

Tue 1/27

4:36 pm-11:33 pm

1 stop8h 57m

$180

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 1/21

5:42 pm-11:59 pm

1 stop28h 17m

San Juan Luis Munoz Marin Intl

Mon 1/26

8:00 am-11:33 pm

1 stop17h 33m

$181

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Mon 1/26

10:16 am-6:40 pm

1 stop6h 24m

San Juan Luis Munoz Marin Intl

Thu 1/29

4:36 pm-11:33 pm

1 stop8h 57m

$201

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Fri 1/23

11:18 am-11:59 pm

1 stop10h 41m

San Juan Luis Munoz Marin Intl

Mon 1/26

4:36 pm-11:33 pm

1 stop8h 57m

$215

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 1/31

12:12 pm-9:54 am

1 stop19h 42m

San Juan Luis Munoz Marin Intl

Sun 2/8

6:00 am-9:21 am

1 stop29h 21m

$216

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 1/24

12:12 pm-11:59 pm

1 stop9h 47m

San Juan Luis Munoz Marin Intl

Sat 1/31

4:36 pm-11:33 pm

1 stop8h 57m

$222

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Sat 5/2

1:30 pm-10:54 pm

1 stop8h 24m

San Juan Luis Munoz Marin Intl

Sat 5/9

6:15 am-12:54 pm

1 stop7h 39m

$225

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Thu 1/29

5:42 pm-10:24 am

1 stop14h 42m

San Juan Luis Munoz Marin Intl

Sun 2/1

5:39 pm-9:21 am

1 stop17h 42m

$228

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 1/21

5:42 pm-11:59 pm

1 stop28h 17m

San Juan Luis Munoz Marin Intl

Wed 1/28

4:40 pm-11:33 pm

2 stops32h 53m

$231

St. LouisSan Juan

STL - SJU

STLSJU

Lambert-St Louis

Wed 1/21

5:42 pm-11:59 pm

1 stop28h 17m

San Juan Luis Munoz Marin Intl

Sun 1/25

8:00 am-9:21 am

1 stop27h 21m

$235

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 $371.

What is the cheapest day to depart on your flight to San Juan Luis Munoz Marin Intl Airport?

On average, the least expensive day to fly to San Juan Luis Munoz Marin Intl Airport from St. Louis is on a Wednesday. momondo users have found tickets for Wednesday departures for as low as $404. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Saturday is the most expensive day to depart from St. Louis because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $646.

What is the cheapest time of day to depart on your flight to San Juan Luis Munoz Marin Intl Airport?

The cheapest time of day to fly to San Juan Luis Munoz Marin Intl Airport is in the evening when flights can be purchased for as low as $310. Flights at noon are often more expensive with an average ticket price of $660.

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 $445 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 $330 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 December 2025, prices for St. Louis to San Juan Luis Munoz Marin Intl Airport flights are approximately 48% more expensive 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 25m

Direct flights

Sun
The fastest flight from St. Louis to San Juan Luis Munoz Marin Intl Airport takes 4h 25m
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 24m.

  • 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 $140Free CancellationRating
5.8
3,092 reviews
Search Frontier flights
Spirit AirlinesPriceFrom $170Free CancellationRating
6.3
8,161 reviews
Search Spirit Airlines flights
DeltaPriceFrom $208Free CancellationRating
7.9
8,011 reviews
Search Delta flights
SouthwestPriceFrom $219Free CancellationRating
8.0
4,253 reviews
Search Southwest flights
United AirlinesPriceFrom $225Free CancellationRating
7.4
9,063 reviews
Search United Airlines flights
American AirlinesPriceFrom $246Free CancellationRating
7.2
11,045 reviews
Search American Airlines flights

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
Caguas
Rio Grande
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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