$661 Cheap Flights from St. Louis (STL) to San Sebastian (EAS)

View $661 flight on Thu, Oct 23, 2025Opens in a new window

Popular airlines from St. Louis Lambert Intl. Airport (STL) to San Sebastian (EAS)

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Cheap Flights from St. Louis to San Sebastian (STL-EAS)

Prices were available within the past 7 days and start at $661 for one-way flights and $1,043 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Iberia
Tue, May 26 - Fri, Jun 5
STL
St. Louis
EAS
San Sebastián
$1,043 Roundtrip, found 2 days ago
$1,043
Roundtrip
found 2 days ago
Select Iberia flight, departing Tue, May 26 from St. Louis to San Sebastián, returning Fri, Jun 5, priced at $1,043 found 2 days ago
British Airways
Tue, May 26 - Fri, Jun 5
STL
St. Louis
EAS
San Sebastián
$1,071 Roundtrip, found 2 days ago
$1,071
Roundtrip
found 2 days ago
Select British Airways flight, departing Tue, May 26 from St. Louis to San Sebastián, returning Fri, Jun 5, priced at $1,071 found 2 days ago
British Airways
Tue, May 26 - Fri, Jun 5
STL
St. Louis
EAS
San Sebastián
$1,094 Roundtrip, found 2 days ago
$1,094
Roundtrip
found 2 days ago
Select British Airways flight, departing Tue, May 26 from St. Louis to San Sebastián, returning Fri, Jun 5, priced at $1,094 found 2 days ago
Iberia
Tue, May 26 - Fri, Jun 5
STL
St. Louis
EAS
San Sebastián
$1,098 Roundtrip, found 2 days ago
$1,098
Roundtrip
found 2 days ago
Select Iberia flight, departing Tue, May 26 from St. Louis to San Sebastián, returning Fri, Jun 5, priced at $1,098 found 2 days ago
British Airways
Tue, May 26 - Fri, Jun 5
STL
St. Louis
EAS
San Sebastián
$1,103 Roundtrip, found 2 days ago
$1,103
Roundtrip
found 2 days ago
Select British Airways flight, departing Tue, May 26 from St. Louis to San Sebastián, returning Fri, Jun 5, priced at $1,103 found 2 days ago
Iberia
Tue, May 26 - Fri, Jun 5
STL
St. Louis
EAS
San Sebastián
$1,152 Roundtrip, found 2 days ago
$1,152
Roundtrip
found 2 days ago
Select Iberia flight, departing Tue, May 26 from St. Louis to San Sebastián, returning Fri, Jun 5, priced at $1,152 found 2 days ago
British Airways
Tue, May 26 - Fri, Jun 5
STL
St. Louis
EAS
San Sebastián
$1,194 Roundtrip, found 2 days ago
$1,194
Roundtrip
found 2 days ago
Select British Airways flight, departing Tue, May 26 from St. Louis to San Sebastián, returning Fri, Jun 5, priced at $1,194 found 2 days ago
Iberia
Tue, May 26 - Fri, Jun 5
STL
St. Louis
EAS
San Sebastián
$1,207 Roundtrip, found 2 days ago
$1,207
Roundtrip
found 2 days ago
Select Iberia flight, departing Tue, May 26 from St. Louis to San Sebastián, returning Fri, Jun 5, priced at $1,207 found 2 days ago
Iberia
Tue, May 26 - Fri, Jun 5
STL
St. Louis
EAS
San Sebastián
$1,226 Roundtrip, found 2 days ago
$1,226
Roundtrip
found 2 days ago
Select Iberia flight, departing Tue, May 26 from St. Louis to San Sebastián, returning Fri, Jun 5, priced at $1,226 found 2 days ago
Finnair
Tue, May 26 - Fri, Jun 5
STL
St. Louis
EAS
San Sebastián
$1,248 Roundtrip, found 2 days ago
$1,248
Roundtrip
found 2 days ago
Select Finnair flight, departing Tue, May 26 from St. Louis to San Sebastián, returning Fri, Jun 5, priced at $1,248 found 2 days ago

Frequently asked questions

How much does a flight from Lambert-St. Louis Intl. Airport (STL) to San Sebastian Airport (EAS) cost?
Grab a cheap one-way flight from $661 or cheap return flight from $1,043 from Lambert-St. Louis Intl. Airport (STL) to San Sebastian Airport (EAS) 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 San Sebastian Airport (EAS)?
The cheapest month to fly from STL to EAS is May, when demand is low. Off-peak months are typically when airlines offer better prices between these airports.
What is the cheapest airline that flies from Lambert-St. Louis Intl. Airport (STL) to San Sebastian Airport (EAS)?
Expedia's filter tool lets you easily compare airlines, flight times and fares all in one place. Customize the search to your preferences, then sort by "Price (lowest to highest)" to see which carrier offers the cheapest STL to EAS flight.
How many flights per day from Lambert-St. Louis Intl. Airport (STL) to San Sebastian Airport (EAS)?
Nonstop flights from Lambert-St. Louis Intl. Airport (STL) to San Sebastian Airport (EAS) 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 travel dates and choose either "1 Stop" or "2+ Stops."
What day of the week has the most flights from STL to EAS?
Friday is usually the busiest day for flights, while Tuesday tends to be the quietest.* Just remember that flight schedules can change based on various factors, including the time of year and airline.*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 San Sebastian Airport (EAS)?
Choose a flight from Lambert-St. Louis Intl. Airport (STL) to San Sebastian Airport (EAS) that takes off before 3 PM to reduce the risk of cancellations. Later departures have a 22% higher chance of being canceled, on average.**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 San Sebastian Airport (EAS) last-minute?
Holding off until just before your trip to book a flight from STL to EAS often results in higher prices. Although you may find some last-minute discounts, there's no guarantee. Be flexible with your travel plans for the best chance of snagging a bargain.
Is it cheaper to book a STL to EAS flight and hotel package?
You can save money by securing a STL to EAS flight and hotel package compared to booking separately. In fact, you could save hundreds of dollars by bundling with Expedia. And it's simple to manage it all in one place. After choosing your preferred accommodations and flights, consider other add-ons like tours, activities and car rentals.
Can I cancel or change the date of my flight from Lambert-St. Louis Intl. Airport (STL) to San Sebastian Airport (EAS)?
Usually, it's possible to cancel or reschedule your STL to EAS flight. However, for bookings made more than 24 hours ago, additional charges may apply. Refer to your airline's policies in your itinerary to see what changes are allowed and whether any costs are involved. You'll also find further details on our Customer Service portal.

Travel information

Origin airport
Lambert-St. Louis Intl.
Destination airport
San Sebastian
Roundtrip price
$1,043
Distance
4397 mi

Book with confidence

St. Louis to San Sebastian Flights

The cheapest times to fly from St. Louis to San Sebastian

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

 

The best time to book a flight from St. Louis to San Sebastian

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

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 San Sebastian in 2025. You can also book with separate airlines for your outbound and return journeys, from $661 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 San Sebastian 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 San Sebastian 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 San Sebastian Flights

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*Available to One Key members.