St. Louis (STL) to San Juan (SJU) flight deal from $225 USD in economy class

UAUnited Airlines

Round Trip•Economy

STL

Lambert-Saint Louis International Airport

St. Louis, United States

SJU

Luis Muñoz Marín International Airport

San Juan, Puerto Rico

$522 USD

-57%$225 USD

Verified Dec 1, 2025 at 5:21 AM

April 2026

Today

Mon

Tue

Wed

Thu

Fri

Sat

Sun

30$316 31$248 1$271 2$459 3$548 4$552 5$543 6$512 7$362 8$323 9$455 10$652 11$623 12$525 13$447 14$346 15$373 16$420 17$350 18$293 19$426 20$293 21$225 22$225 23$293 24$444 25$225 26$225 27$225 28$225 29$225 30$339 1 2 3

Rare Availability

5% of dates checked are available within 10% of the lowest price

Tuesday, April 7th, 2026

10 round-trip options

Returning

Sun, Apr 12, 2026•5 Day Trip

$646 USD

Google Flights

Returning

Mon, Apr 13, 2026•6 Day Trip

$532 USD

Google Flights

Returning

Tue, Apr 14, 2026•7 Day Trip

$409 USD

Google Flights

Returning

Wed, Apr 15, 2026•8 Day Trip

$362 USD

Google Flights

Returning

Thu, Apr 16, 2026•9 Day Trip

$362 USD

Google Flights

Returning

Fri, Apr 17, 2026•10 Day Trip

$430 USD

Google Flights

Returning

Sat, Apr 18, 2026•11 Day Trip

$430 USD

Google Flights

Returning

Sun, Apr 19, 2026•12 Day Trip

$548 USD

Google Flights

Returning

Mon, Apr 20, 2026•13 Day Trip

$532 USD

Google Flights

Returning

Tue, Apr 21, 2026•14 Day Trip

$384 USD

Google Flights