$1,226 Cheap Flights from Cardiff (CWL) to Seattle (SEA)

View $1,226 flight on Wed, Oct 22, 2025Opens in a new window

Popular airlines from Cardiff International Airport (CWL) to Seattle-Tacoma International Airport (SEA)

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Cheap Flights from Cardiff to Seattle (CWL-SEA)

Prices were available within the past 7 days and start at $1,226 for one-way flights and $1,173 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Sat, Aug 16 - Sun, Aug 24
CWL
Cardiff
SEA
Seattle
$1,173 Roundtrip, found 1 day ago
$1,173
Roundtrip
found 1 day ago
Select Delta flight, departing Sat, Aug 16 from Cardiff to Seattle, returning Sun, Aug 24, priced at $1,173 found 1 day ago
Delta
Sat, Aug 16 - Sun, Aug 24
CWL
Cardiff
SEA
Seattle
$1,177 Roundtrip, found 1 day ago
$1,177
Roundtrip
found 1 day ago
Select Delta flight, departing Sat, Aug 16 from Cardiff to Seattle, returning Sun, Aug 24, priced at $1,177 found 1 day ago
Virgin Atlantic
Wed, Aug 13 - Sun, Aug 17
CWL
Cardiff
SEA
Seattle
$1,196 Roundtrip, found 1 day ago
$1,196
Roundtrip
found 1 day ago
Select Virgin Atlantic flight, departing Wed, Aug 13 from Cardiff to Seattle, returning Sun, Aug 17, priced at $1,196 found 1 day ago
Air France
Sat, Aug 16 - Sun, Aug 24
CWL
Cardiff
SEA
Seattle
$1,199 Roundtrip, found 1 day ago
$1,199
Roundtrip
found 1 day ago
Select Air France flight, departing Sat, Aug 16 from Cardiff to Seattle, returning Sun, Aug 24, priced at $1,199 found 1 day ago
Delta
Sat, Aug 16 - Sun, Aug 24
CWL
Cardiff
SEA
Seattle
$1,204 Roundtrip, found 1 day ago
$1,204
Roundtrip
found 1 day ago
Select Delta flight, departing Sat, Aug 16 from Cardiff to Seattle, returning Sun, Aug 24, priced at $1,204 found 1 day ago
Virgin Atlantic
Wed, Aug 13 - Sun, Aug 17
CWL
Cardiff
SEA
Seattle
$1,215 Roundtrip, found 1 day ago
$1,215
Roundtrip
found 1 day ago
Select Virgin Atlantic flight, departing Wed, Aug 13 from Cardiff to Seattle, returning Sun, Aug 17, priced at $1,215 found 1 day ago
KLM
Sat, Aug 16 - Sun, Aug 24
CWL
Cardiff
SEA
Seattle
$1,216 Roundtrip, found 1 day ago
$1,216
Roundtrip
found 1 day ago
Select KLM flight, departing Sat, Aug 16 from Cardiff to Seattle, returning Sun, Aug 24, priced at $1,216 found 1 day ago
KLM
Sat, Aug 16 - Sun, Aug 24
CWL
Cardiff
SEA
Seattle
$1,221 Roundtrip, found 1 day ago
$1,221
Roundtrip
found 1 day ago
Select KLM flight, departing Sat, Aug 16 from Cardiff to Seattle, returning Sun, Aug 24, priced at $1,221 found 1 day ago
Delta
Sat, Aug 16 - Sun, Aug 24
CWL
Cardiff
SEA
Seattle
$1,226 Roundtrip, found 1 day ago
$1,226
Roundtrip
found 1 day ago
Select Delta flight, departing Sat, Aug 16 from Cardiff to Seattle, returning Sun, Aug 24, priced at $1,226 found 1 day ago
KLM
Sat, Aug 16 - Sun, Aug 24
CWL
Cardiff
SEA
Seattle
$1,226 Roundtrip, found 1 day ago
$1,226
Roundtrip
found 1 day ago
Select KLM flight, departing Sat, Aug 16 from Cardiff to Seattle, returning Sun, Aug 24, priced at $1,226 found 1 day ago
Flights from Cardiff (CWL) to Seattle (SEA)
Origin airport
Cardiff Intl.
Destination airport
Seattle - Tacoma Intl.
Airlines serving
Air France, Delta, KLM, Virgin Atlantic
Roundtrip price
$1,172
Distance
4712 mi

Cardiff to Seattle Flights

The cheapest times to fly from Cardiff to Seattle

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

 

The best time to book a flight from Cardiff to Seattle

Sunday is one of the best days to book for cheap flights from Cardiff to Seattle: 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 Cardiff to Seattle

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 Cardiff to Seattle in 2025. You can also book with separate airlines for your outbound and return journeys, from $1,226 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 Cardiff to Seattle 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 Cardiff to Seattle 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 Cardiff Intl. Airport (CWL) to Seattle - Tacoma Intl. Airport (SEA) cost?
Discover the latest flight deals from CWL to SEA 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 CWL to SEA?
The cheapest flights from CWL to SEA 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 CWL to SEA?
Use the filter tool on Expedia to compare airlines and find the cheapest carrier that'll take you from CWL to SEA. Sort your results by "Price (lowest to highest)" to snap up a great deal.
How many flights per day from Cardiff Intl. Airport (CWL) to Seattle - Tacoma Intl. Airport (SEA)?
You'll have to catch a flight with a layover when traveling from Cardiff Intl. Airport (CWL) to Seattle - Tacoma Intl. Airport (SEA). Direct flights don't operate daily on this route. However, just filter your search to include one or more stops to find the best option for your trip.
What day of the week has the most flights from CWL to SEA?
Typically you'll find the most flight options available on a Friday. Tuesdays tend to be the quietest.* But this can vary depending on the time of year, carrier 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 Cardiff Intl. Airport (CWL) to Seattle - Tacoma Intl. Airport (SEA)?
Opt for a flight from Cardiff Intl. Airport (CWL) to Seattle - Tacoma Intl. Airport (SEA) that leaves before 3 PM to reduce the likelihood of delays. Departures after this hour 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 Cardiff Intl. Airport (CWL) to Seattle - Tacoma Intl. Airport (SEA) last-minute?
Holding off until right before your break to book a ticket from CWL to SEA often results in higher prices. While you might find some last-minute deals, there's no guarantee. Be flexible with your itinerary for the best chance of snagging a bargain.
Is it cheaper to book a CWL to SEA flight and hotel package?
Booking a CWL to SEA flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the convenience of organizing your travels all in one place. Select from our impressive range of accommodations and then add flights, activities and car rentals 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 Cardiff Intl. Airport (CWL) to Seattle - Tacoma Intl. Airport (SEA)?
If you reserved your CWL to SEA flight within the last 24 hours, you may be able to cancel or modify it without fees. Depending on the airline and the ticket type you purchased, additional charges may apply for changes after that time. Airline policies and contact information can be found in your itinerary or confirmation email. Or, visit our Customer Service portal if you'd like more information.

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*Available to One Key members.