$436 Cheap Flights from Seattle (SEA) to Belfast (BFS)

View $436 flight on Wed, Nov 5, 2025Opens in a new window

Popular airlines from Seattle-Tacoma International Airport (SEA) to Belfast International Airport (BFS)

Cheap Flights from Seattle to Belfast (SEA-BFS)

Prices were available within the past 7 days and start at $436 for one-way flights and $625 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

American Airlines
Mon, Aug 11 - Wed, Aug 20
SEA
Seattle
BHD
Belfast
$625 Roundtrip, found 2 days ago
$625
Roundtrip
found 2 days ago
Select American Airlines flight, departing Mon, Aug 11 from Seattle to Belfast, returning Wed, Aug 20, priced at $625 found 2 days ago
American Airlines
Mon, Aug 11 - Wed, Aug 20
SEA
Seattle
BHD
Belfast
$628 Roundtrip, found 2 days ago
$628
Roundtrip
found 2 days ago
Select American Airlines flight, departing Mon, Aug 11 from Seattle to Belfast, returning Wed, Aug 20, priced at $628 found 2 days ago
American Airlines
Mon, Aug 11 - Wed, Aug 20
SEA
Seattle
BHD
Belfast
$630 Roundtrip, found 2 days ago
$630
Roundtrip
found 2 days ago
Select American Airlines flight, departing Mon, Aug 11 from Seattle to Belfast, returning Wed, Aug 20, priced at $630 found 2 days ago
American Airlines
Mon, Aug 11 - Wed, Aug 20
SEA
Seattle
BHD
Belfast
$633 Roundtrip, found 2 days ago
$633
Roundtrip
found 2 days ago
Select American Airlines flight, departing Mon, Aug 11 from Seattle to Belfast, returning Wed, Aug 20, priced at $633 found 2 days ago
American Airlines
Mon, Aug 11 - Wed, Aug 20
SEA
Seattle
BHD
Belfast
$645 Roundtrip, found 2 days ago
$645
Roundtrip
found 2 days ago
Select American Airlines flight, departing Mon, Aug 11 from Seattle to Belfast, returning Wed, Aug 20, priced at $645 found 2 days ago
American Airlines
Mon, Aug 11 - Wed, Aug 20
SEA
Seattle
BHD
Belfast
$650 Roundtrip, found 2 days ago
$650
Roundtrip
found 2 days ago
Select American Airlines flight, departing Mon, Aug 11 from Seattle to Belfast, returning Wed, Aug 20, priced at $650 found 2 days ago
British Airways
Mon, Aug 11 - Wed, Aug 20
SEA
Seattle
BHD
Belfast
$696 Roundtrip, found 2 days ago
$696
Roundtrip
found 2 days ago
Select British Airways flight, departing Mon, Aug 11 from Seattle to Belfast, returning Wed, Aug 20, priced at $696 found 2 days ago
KLM
Mon, Aug 11 - Wed, Aug 20
SEA
Seattle
BHD
Belfast
$738 Roundtrip, found 2 days ago
$738
Roundtrip
found 2 days ago
Select KLM flight, departing Mon, Aug 11 from Seattle to Belfast, returning Wed, Aug 20, priced at $738 found 2 days ago
Delta
Wed, Oct 1 - Wed, Oct 15
SEA
Seattle
BHD
Belfast
$809 Roundtrip, found 2 days ago
$809
Roundtrip
found 2 days ago
Select Delta flight, departing Wed, Oct 1 from Seattle to Belfast, returning Wed, Oct 15, priced at $809 found 2 days ago
Virgin Atlantic
Wed, Oct 15 - Wed, Oct 22
SEA
Seattle
BHD
Belfast
$809 Roundtrip, found 1 day ago
$809
Roundtrip
found 1 day ago
Select Virgin Atlantic flight, departing Wed, Oct 15 from Seattle to Belfast, returning Wed, Oct 22, priced at $809 found 1 day ago

Find the cheapest month to fly from Seattle (SEA) to Belfast (BFS)

February is typically the cheapest month to fly

From $578 - $1,025 per traveler.

Graph displaying average flight prices per month

Alternative airports near Belfast

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

Select flight to George Best Belfast City BHD. Cheapest and Closest option available. Average driving time to city center is 6 minutes. Flights from $1,312
BHD
George Best Belfast City
CheapestClosest
Average driving time to city center6 min
Flights from $1,312
Flights from Seattle (SEA) to Belfast (BHD)
Origin airport
Seattle - Tacoma Intl.
Destination airport
George Best Belfast City
Roundtrip price
$625
Distance
4475 mi

Seattle to Belfast Flights

The cheapest times to fly from Seattle to Belfast

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

 

The best time to book a flight from Seattle to Belfast

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

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 Belfast in 2025. You can also book with separate airlines for your outbound and return journeys, from $436 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 Belfast 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 Belfast 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 Seattle - Tacoma Intl. Airport (SEA) to Belfast Intl. Airport (BFS) cost?
Discover the latest flight deals from SEA to BFS 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 SEA to BFS?
The cheapest flights from SEA to BFS 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 SEA to BFS?
Use the filter tool on Expedia to compare airlines and find the cheapest carrier that'll take you from SEA to BFS. Sort your results by "Price (lowest to highest)" to snap up a great deal.
How many flights per day from Seattle - Tacoma Intl. Airport (SEA) to Belfast Intl. Airport (BFS)?
You'll have to hop on a flight with a layover when traveling from Seattle - Tacoma Intl. Airport (SEA) to Belfast Intl. Airport (BFS). Direct flights don't operate daily on this route. However, just filter your search to include one or more stops to discover an option that works for you.
What day of the week has the most flights from SEA to BFS?
You'll usually find Tuesday the quietest day for flights, while Fridays are often the busiest.* However this can vary 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 Belfast Intl. Airport (BFS)?
Book a flight from Seattle - Tacoma Intl. Airport (SEA) to Belfast Intl. Airport (BFS) that takes off before 3 PM to reduce the risk of delays and cancellations. 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 Seattle - Tacoma Intl. Airport (SEA) to Belfast Intl. Airport (BFS) last-minute?
Last-minute bookings from SEA to BFS are generally more expensive. To secure the cheapest rates, start searching for flights as early as possible. That said, if you're flexible with your travel dates, you may land a cheap fare right before your journey.
Is it cheaper to book a SEA to BFS flight and hotel package?
Compared with arranging flights and hotels separately, booking a SEA to BFS flight and hotel package with Expedia could result in significant savings. What's more, having everything in one convenient place will take the hassle out of travel planning. Simply pick your flights and choose from our extensive range of hotels, then personalize your trip with extras like tours, activities and car rentals.
Can I cancel or change the date of my flight from Seattle - Tacoma Intl. Airport (SEA) to Belfast Intl. Airport (BFS)?
If you reserved your SEA to BFS flight in the last 24 hours, you may be able to cancel or modify it at no cost. Depending on the airline and the fare type you purchased, additional charges may apply for changes beyond that time. Airline policies and contact information can be found in your itinerary or confirmation email. Or, visit our Customer Service portal for more information.

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*Available to One Key members.