$529 Cheap Flights from Seattle (SEA) to Castries (SLU)

View $529 flight on Sun, Dec 14, 2025Opens in a new window

Popular airlines from Seattle-Tacoma International Airport (SEA) to George F. L. Charles Airport (SLU)

Cheap Flights from Seattle to Castries (SEA-SLU)

Prices were available within the past 7 days and start at $529 for one-way flights and $1,190 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

United
Tue, Jan 20 - Mon, Feb 2
SEA
Seattle
SLU
Castries
$1,190 Roundtrip, found 6 days ago
$1,190
Roundtrip
found 6 days ago
Select United flight, departing Tue, Jan 20 from Seattle to Castries, returning Mon, Feb 2, priced at $1,190 found 6 days 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 $718
UVF
Hewanorra Intl.
Cheapest
Average driving time to city center53 min
Flights from $718

Frequently asked questions

How much does a flight from Seattle - Tacoma Intl. Airport (SEA) to George F. L. Charles Airport (SLU) cost?
Secure a cheap one-way flight from $529 or cheap return flight from $1,190 from Seattle - Tacoma Intl. Airport (SEA) 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 offers on this route.
What is the cheapest month to fly from Seattle - Tacoma Intl. Airport (SEA) to George F. L. Charles Airport (SLU)?
Planning your getaway for January may help you find better deals, as it's the cheapest month for flights between SEA and SLU. You'll typically find the lowest prices during off-peak months.
What is the cheapest airline that flies from Seattle - Tacoma Intl. Airport (SEA) to George F. L. Charles Airport (SLU)?
Use the filter tool on Expedia to compare airlines and find the most affordable carrier that'll fly you from SEA to SLU. Then, sort your results by "Price (lowest to highest)" to score a good deal.
How many flights per day from Seattle - Tacoma Intl. Airport (SEA) to George F. L. Charles Airport (SLU)?
There aren't any daily direct flights from Seattle - Tacoma Intl. Airport (SEA) to George F. L. Charles Airport (SLU). But you can book flights with layovers. Filter your search results on Expedia to include one or two stops, and you'll be on your way before you know it.
What day of the week has the most flights from SEA to SLU?
You'll typically find Tuesday the quietest day for flights, while Fridays are often the busiest.* However this can change 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 Seattle - Tacoma Intl. Airport (SEA) to George F. L. Charles Airport (SLU)?
To touch down at George F. L. Charles Airport (SLU) on schedule, book a flight that takes off from Seattle - Tacoma Intl. Airport (SEA) before 3 PM. The chance of cancellations is 22% higher, on average, for departures after this hour.**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 Seattle - Tacoma Intl. Airport (SEA) to George F. L. Charles Airport (SLU) last-minute?
Booking your flight from SEA to SLU right before your trip is generally more expensive. However, if you're flexible with your travel dates and times, you could grab a cheap last-minute fare.
Is it cheaper to book a SEA to SLU flight and hotel package?
Booking a SEA to SLU flight and hotel package is generally cheaper than booking separately. With Expedia, you can enjoy the convenience of organizing your trip in one place. Choose from our extensive range of accommodations and then add car rentals, activities and flights to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Seattle - Tacoma Intl. Airport (SEA) to George F. L. Charles Airport (SLU)?
In most instances, you're able to cancel or reschedule your SEA to SLU flight. However, there may be additional fees, especially if your booking was made more than 24 hours ago. Check your itinerary for the airline's guidelines and fees on flight changes, or if you'd like further information, go to our Customer Service portal.

Travel information

Origin airport
Seattle - Tacoma Intl.
Destination airport
George F. L. Charles
Roundtrip price
$1,190
Distance
4175 mi

Book with confidence

Seattle to Castries Flights

The cheapest times to fly from Seattle 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 Seattle to Castries are during the month of January. You can find some of the cheapest flights from Seattle to Castries with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Seattle to Castries

Sunday is one of the best days to book for cheap flights from Seattle 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 Seattle 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 Seattle to Castries in 2025. You can also book with separate airlines for your outbound and return journeys, from $529 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 Seattle 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 Seattle 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.

 

Seattle to Castries Flights

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*Available to One Key members.