Cheap Flights from St. Louis (STL) to Ulsan (USN)

Popular airlines from St. Louis Lambert Intl. Airport (STL) to Ulsan (USN)

Frequently asked questions

How much does a flight from Lambert-St. Louis Intl. Airport (STL) to Ulsan Airport (USN) cost?
Lock in a cheap one-way flight or cheap return flight from Lambert-St. Louis Intl. Airport (STL) to Ulsan Airport (USN) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to see our cheapest flight deals on this route.
What is the cheapest month to fly from Lambert-St. Louis Intl. Airport (STL) to Ulsan Airport (USN)?
Planning your trip for is a great way to save, as it's the cheapest month for flights between STL and USN. You'll usually find the lowest prices during the off-season.
What is the cheapest airline that flies from Lambert-St. Louis Intl. Airport (STL) to Ulsan Airport (USN)?
Use the filter tool on Expedia to compare different airlines and find the cheapest carrier that'll take you from STL to USN. Then, sort your results by "Price (lowest to highest)" to snag the best deal available.
How many flights per day from Lambert-St. Louis Intl. Airport (STL) to Ulsan Airport (USN)?
Direct flights from Lambert-St. Louis Intl. Airport (STL) to Ulsan Airport (USN) aren't available daily, so you'll have to take a flight with a layover. Explore your options with Expedia's filter tool. Enter your dates and select either "1 Stop" or "2+ Stops."
What day of the week has the most flights from STL to USN?
You'll typically find Tuesday the quietest day for flights, while Fridays tend to be the busiest.* However this can vary from season to season and during public holidays or peak travel times.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Lambert-St. Louis Intl. Airport (STL) to Ulsan Airport (USN)?
To reach Ulsan Airport (USN) on time, pick a flight that leaves Lambert-St. Louis Intl. Airport (STL) before 3 PM. The chance of cancellations is 22% higher, on average, for departures after this time.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
Is it cheaper to buy a plane ticket from Lambert-St. Louis Intl. Airport (STL) to Ulsan Airport (USN) last-minute?
Waiting until just before your departure to book a ticket from STL to USN often results in higher prices. While you may come across some last-minute offers, they aren't always guaranteed. Allow some flexibility in your schedule for a better chance of snagging a bargain.
Is it cheaper to book a STL to USN flight and hotel package?
Compared with arranging flights and hotels separately, booking a STL to USN flight and hotel package with Expedia could result in significant savings. What's more, having everything in one convenient place will take the stress out of travel planning. Simply secure your flights and choose from our wide range of stays, then customize your trip with other add-ons like activities and car rentals.
Can I cancel or change the date of my flight from Lambert-St. Louis Intl. Airport (STL) to Ulsan Airport (USN)?
Typically, you're able to cancel or reschedule your STL to USN flight. However, there may be additional charges, especially if you booked more than 24 hours ago. Double-check your itinerary for the airline's policies and fees on flight changes, or if you'd like further details, go to our Customer Service portal.

Travel information

Origin airport
Lambert-St. Louis Intl.
Destination airport
Ulsan
Distance
6708 mi

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St. Louis to Ulsan Flights

The cheapest times to fly from St. Louis to Ulsan

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from St. Louis to Ulsan are during the month of . You can find some of the cheapest flights from St. Louis to Ulsan with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from St. Louis to Ulsan

Sunday is one of the best days to book for cheap flights from St. Louis to Ulsan: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from St. Louis to Ulsan

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from St. Louis to Ulsan in 2025. You can also book with separate airlines for your outbound and return journeys, from one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap St. Louis to Ulsan flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your St. Louis to Ulsan airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

St. Louis to Ulsan Flights

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*Available to One Key members.