$532 Cheap Flights from Washington (IAD) to Castries (SLU)

View $532 flight on Mon, Dec 29, 2025Opens in a new window

Popular airlines from Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU)

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Cheap Flights from Washington to Castries (IAD-SLU)

Prices were available within the past 7 days and start at $532 for one-way flights and $1,164 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

United
Sun, Dec 14 - Thu, Dec 18
IAD
Washington
SLU
Castries
$1,164 Roundtrip, found 14 hours ago
$1,164
Roundtrip
found 14 hours ago
Select United flight, departing Sun, Dec 14 from Washington to Castries, returning Thu, Dec 18, priced at $1,164 found 14 hours ago

Alternative airports near Castries

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Hewanorra Intl. UVF. Cheapest option available. Average driving time to city center is 53 minutes. Flights from $610
UVF
Hewanorra Intl.
Cheapest
Average driving time to city center53 min
Flights from $610
Flights from Washington (IAD) to Castries (SLU)
Origin airport
Washington Dulles Intl.
Destination airport
George F. L. Charles
Roundtrip price
$1,163
Distance
1993 mi

Washington to Castries Flights

The cheapest times to fly from Washington to Castries

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 Washington to Castries are during the month of December. You can find some of the cheapest flights from Washington to Castries with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Washington to Castries

Sunday is one of the best days to book for cheap flights from Washington to Castries: 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 Washington to Castries

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 Washington to Castries in 2025. You can also book with separate airlines for your outbound and return journeys, from $532 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 Washington to Castries 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 Washington to Castries 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 Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU) cost?
Get a cheap one-way flight from $532 or cheap return flight from $1,164 from Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU) 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 Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU)?
December is the cheapest month to fly from IAD to SLU. Avoiding peak travel times is often the key to finding better fares.
What is the cheapest airline that flies from Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU)?
To find the cheapest airline that'll fly you from IAD to SLU, use Expedia's filter tool. Tailor your search based on what matters most to you, such as preferred carriers and cabin class. You can then sort your results by "Price (lowest to highest)" to see the cheapest fares upfront.
How many flights per day from Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU)?
You'll need to book a flight with a layover when traveling from Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU). Direct flights don't operate daily on this route. However, simply 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 IAD to SLU?
Usually you'll find the widest variety of flight choices on a Friday. Tuesdays tend to be the quietest.* However, this can vary based on the airline, season and other factors.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU)?
To avoid possible delays on the Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU) route, aim to travel before 3 PM. Departures after this time have a 22% higher chance of being 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 Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU) last-minute?
Waiting until right before your break to book a flight from IAD to SLU generally means paying more. While you may find some last-minute discounts, they're not always guaranteed. Keep your travel plans flexible to maximize your chances of snagging a bargain.
Is it cheaper to book an IAD to SLU flight and hotel package?
Securing an IAD to SLU flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the convenience of organizing your trip in one place. Select from our extensive range of accommodations and then add car rentals, flights and activities to your booking. Bundle it all together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Washington Dulles Intl. Airport (IAD) to George F. L. Charles Airport (SLU)?
Generally, it's possible to reschedule or cancel your IAD to SLU flight. However, if the booking was made more than 24 hours ago, additional fees may apply. Refer to your airline's policies in your itinerary to see what changes are allowed and if any costs are involved. You'll also find more information on our Customer Service portal.

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*Available to One Key members.