$552 Cheap Flights from St. Louis (STL) to Cardiff (CWL)

View $552 flight on Wed, Oct 1, 2025Opens in a new window

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Cheap Flights from St. Louis to Cardiff (STL-CWL)

Prices were available within the past 7 days and start at $552 for one-way flights and $867 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Mon, May 12 - Tue, May 13
STL
St. Louis
CWL
Cardiff
$867 Roundtrip, found 1 day ago
$867
Roundtrip
found 1 day ago
Select Delta flight, departing Mon, May 12 from St. Louis to Cardiff, returning Tue, May 13, priced at $867 found 1 day ago
Virgin Atlantic
Wed, Aug 6 - Tue, Aug 26
STL
St. Louis
CWL
Cardiff
$887 Roundtrip, found 3 days ago
$887
Roundtrip
found 3 days ago
Select Virgin Atlantic flight, departing Wed, Aug 6 from St. Louis to Cardiff, returning Tue, Aug 26, priced at $887 found 3 days ago
Delta
Mon, May 12 - Wed, May 14
STL
St. Louis
CWL
Cardiff
$897 Roundtrip, found 1 day ago
$897
Roundtrip
found 1 day ago
Select Delta flight, departing Mon, May 12 from St. Louis to Cardiff, returning Wed, May 14, priced at $897 found 1 day ago
Delta
Wed, Oct 22 - Wed, Nov 12
STL
St. Louis
CWL
Cardiff
$899 Roundtrip, found 3 days ago
$899
Roundtrip
found 3 days ago
Select Delta flight, departing Wed, Oct 22 from St. Louis to Cardiff, returning Wed, Nov 12, priced at $899 found 3 days ago
KLM
Wed, Oct 1 - Wed, Oct 29
STL
St. Louis
CWL
Cardiff
$913 Roundtrip, found 8 hours ago
$913
Roundtrip
found 8 hours ago
Select KLM flight, departing Wed, Oct 1 from St. Louis to Cardiff, returning Wed, Oct 29, priced at $913 found 8 hours ago
Delta
Wed, Oct 1 - Wed, Oct 29
STL
St. Louis
CWL
Cardiff
$919 Roundtrip, found 8 hours ago
$919
Roundtrip
found 8 hours ago
Select Delta flight, departing Wed, Oct 1 from St. Louis to Cardiff, returning Wed, Oct 29, priced at $919 found 8 hours ago
Virgin Atlantic
Mon, May 12 - Wed, May 21
STL
St. Louis
CWL
Cardiff
$923 Roundtrip, found 1 day ago
$923
Roundtrip
found 1 day ago
Select Virgin Atlantic flight, departing Mon, May 12 from St. Louis to Cardiff, returning Wed, May 21, priced at $923 found 1 day ago
Delta
Wed, Oct 22 - Wed, Nov 12
STL
St. Louis
CWL
Cardiff
$925 Roundtrip, found 3 days ago
$925
Roundtrip
found 3 days ago
Select Delta flight, departing Wed, Oct 22 from St. Louis to Cardiff, returning Wed, Nov 12, priced at $925 found 3 days ago
Delta
Mon, Aug 11 - Sat, Aug 23
STL
St. Louis
CWL
Cardiff
$937 Roundtrip, found 3 days ago
$937
Roundtrip
found 3 days ago
Select Delta flight, departing Mon, Aug 11 from St. Louis to Cardiff, returning Sat, Aug 23, priced at $937 found 3 days ago
KLM
Wed, Oct 1 - Wed, Oct 29
STL
St. Louis
CWL
Cardiff
$939 Roundtrip, found 8 hours ago
$939
Roundtrip
found 8 hours ago
Select KLM flight, departing Wed, Oct 1 from St. Louis to Cardiff, returning Wed, Oct 29, priced at $939 found 8 hours ago
Flights from St. Louis (STL) to Cardiff (CWL)
Origin airport
Lambert-St. Louis Intl.
Destination airport
Cardiff Intl.
Airlines serving
Delta, KLM, Virgin Atlantic
Roundtrip price
$867
Distance
4079 mi

St. Louis to Cardiff Flights

The cheapest times to fly from St. Louis to Cardiff

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 Cardiff are during the month of May. You can find some of the cheapest flights from St. Louis to Cardiff with Expedia's search tool and vast selection of airlines.

 

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

Sunday is one of the best days to book for cheap flights from St. Louis to Cardiff: 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 Cardiff

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 Cardiff in 2025. You can also book with separate airlines for your outbound and return journeys, from $552 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 Cardiff 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 Cardiff 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.

 

Frequently asked questions

How much does a flight from Lambert-St. Louis Intl. Airport (STL) to Cardiff Intl. Airport (CWL) cost?
Discover the latest flight deals from STL to CWL by entering your preferred travel dates and searching on Expedia. Easily compare prices by departure date if you have flexibility with your schedule and use handy filters to explore prices for your preferred journey. As a member of One Key™, our free loyalty program, you can use Price Tracking to watch fares and receive notifications if prices go up or down.
What is the cheapest month to fly from STL to CWL?
The cheapest flights from STL to CWL are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
What is the cheapest airline that flies from STL to CWL?
Use the filter tool on Expedia to compare airlines and find the cheapest carrier that’ll take you from STL to CWL. Sort your results by “Price (lowest to highest)” to snap up a great deal.
How many flights per day from Lambert-St. Louis Intl. Airport (STL) to Cardiff Intl. Airport (CWL)?
You’ll have to catch a flight with a layover when traveling from Lambert-St. Louis Intl. Airport (STL) to Cardiff Intl. Airport (CWL). Direct flights don’t operate daily on this route. However, just filter your search to include one or more stops to find an option that works for you.
What day of the week has the most flights from STL to CWL?
Friday is usually the busiest day for flights, while Tuesday is often the quietest.* Just remember that flight schedules can vary depending on a range of factors, such as the carrier and season.*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 Cardiff Intl. Airport (CWL)?
Opt for a flight from Lambert-St. Louis Intl. Airport (STL) to Cardiff Intl. Airport (CWL) that takes off before 3 PM to reduce the likelihood of delays. Departures after this time are on average 22% more likely to be canceled.**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 Cardiff Intl. Airport (CWL) last-minute?
Last-minute fares from STL to CWL are usually more expensive. To secure the cheapest rates, start looking for flights well ahead of time. That being said, if you’re flexible with your travel dates, it’s possible to land a cheap fare right before you leave.
Is it cheaper to book a STL to CWL flight and hotel package?
Compared with arranging hotels and flights separately, booking a STL to CWL flight and hotel package with Expedia could result in significant savings. What’s more, managing everything in one place takes the hassle out of travel planning. Simply secure your flights and choose from our extensive range of hotels, then tailor your trip with extras like tours, activities and car rentals.
Can I cancel or change the date of my flight from Lambert-St. Louis Intl. Airport (STL) to Cardiff Intl. Airport (CWL)?
In most instances, you’re able to cancel or reschedule your STL to CWL flight. However, additional fees may apply, especially if you booked more than 24 hours ago. Double-check your itinerary for the airline’s fees and guidelines on flight changes, or if you need more details, visit our Customer Service portal.

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*Available to One Key members.