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$612+ Cheap flights from Seattle (SEA) to Belfast

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 10/13. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — BHD
Oct 15 — Oct 221
Wed 10/15
Wed 10/22
1 adult, Economy
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Cheap flight deals from Seattle to Belfast

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to Belfast (BF1). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated September 15, 2025.

Round-trip from

$612
(Trip.com)

Popular in

December

Cheapest in

March

Average price

$985
From Seattle/Tacoma Intl to Belfast
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Highest demand for flights based on searches. 7% potential increase in price ($72 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($29 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Find flight deals from Seattle to Belfast

Cheapest flights from Seattle to Belfast
Explore the most affordable flight options available from Seattle to Belfast. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 15, 2025.

This Trip.com deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/133:45 pmSEA - BHD
2 stops17h 45mMultiple Airlines
Mon 10/206:40 amBHD - SEA
2 stops22h 00mMultiple Airlines
Deal found 9/15$612
This American Airlines deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/138:20 pmSEA - BHD
1 stop16h 25mAmerican Airlines
Mon 10/201:50 pmBHD - SEA
1 stop29h 20mAmerican Airlines
Deal found 9/15$651
This Mytrip deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/133:45 pmSEA - BFS
2 stops20h 40mMultiple Airlines
Mon 10/206:10 amBFS - SEA
2 stops22h 30mMultiple Airlines
Deal found 9/15$723
This Cheapflightsfares deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/11:30 pmSEA - BHD
1 stop14h 25mBritish Airways
Wed 10/88:15 pmBHD - SEA
1 stop23h 20mBritish Airways
Deal found 9/14$723
This Travelocity deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Travelocity is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/17:48 amSEA - BHD
2 stops20h 07mIberia
Wed 10/86:50 amBHD - SEA
1 stop12h 45mIberia
Deal found 9/14$741
This British Airways deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure British Airways is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/36:50 pmSEA - BHD
1 stop13h 45mBritish Airways
Sun 12/78:25 pmBHD - SEA
1 stop28h 30mBritish Airways
Deal found 9/14$743
This American Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/33:00 pmSEA - BHD
2 stops19h 15mAmerican Airlines
Fri 10/1011:55 amBHD - SEA
2 stops19h 01mAmerican Airlines
Deal found 9/14$757
This Mytrip deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/17:00 pmSEA - BFS
2 stops17h 35mMultiple Airlines
Wed 10/86:10 amBFS - SEA
2 stops22h 30mMultiple Airlines
Deal found 9/14$770
This Delta deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/35:40 pmSEA - BHD
1 stop19h 35mDelta
Fri 10/106:30 amBHD - SEA
1 stop17h 35mDelta
Deal found 9/15$779
This FlightHub deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/33:40 pmSEA - BHD
2 stops21h 05mBritish Airways
Fri 10/106:35 amBHD - SEA
1 stop13h 00mBritish Airways
Deal found 9/14$812
This KLM deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/35:40 pmSEA - BHD
1 stop15h 15mKLM
Fri 10/106:30 amBHD - SEA
1 stop17h 35mKLM
Deal found 9/14$819

Cheapflights Fare Finder

 
Customize your flight search to find flights from Seattle to Belfast that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated September 15, 2025.
Use the filters below to find and compare flights from Seattle to Belfast that are best for you.

Fly from

Seattle

Fly to

Belfast

Route

Depart

Return

Price

SeattleBelfast

SEA - BHD

SEABHD

Seattle/Tacoma Intl

Sat 3/7

1:35 pm-2:15 pm

1 stop16h 40m

Belfast City

Wed 3/18

11:25 am-5:55 pm

1 stop13h 30m

$703

SeattleBelfast

SEA - BHD

SEABHD

Seattle/Tacoma Intl

Sat 3/7

1:35 pm-2:15 pm

1 stop16h 40m

Belfast City

Tue 3/17

11:25 am-5:55 pm

1 stop13h 30m

$703

SeattleBelfast

SEA - BHD

SEABHD

Seattle/Tacoma Intl

Sat 3/7

1:35 pm-2:15 pm

1 stop16h 40m

Belfast City

Tue 3/17

11:25 am-12:49 am

2 stops20h 24m

$714

SeattleBelfast

SEA - BHD

SEABHD

Seattle/Tacoma Intl

Sat 3/7

6:50 pm-4:45 pm

1 stop13h 55m

Belfast City

Wed 3/18

11:25 am-12:49 am

2 stops20h 24m

$716

SeattleBelfast

SEA - BHD

SEABHD

Seattle/Tacoma Intl

Sat 3/7

1:34 pm-2:15 pm

2 stops16h 41m

Belfast City

Tue 3/17

6:35 am-11:08 pm

2 stops23h 33m

$722

SeattleBelfast

SEA - BFS

SEABFS

Seattle/Tacoma Intl

Mon 10/13

3:45 pm-8:25 pm

2 stops20h 40m

Belfast Intl

Mon 10/20

6:10 am-8:40 pm

2 stops22h 30m

$723

SeattleBelfast

SEA - BHD

SEABHD

Seattle/Tacoma Intl

Wed 10/1

1:30 pm-11:55 am

1 stop14h 25m

Belfast City

Wed 10/8

8:15 pm-11:35 am

1 stop23h 20m

$723

SeattleBelfast

SEA - BHD

SEABHD

Seattle/Tacoma Intl

Wed 10/1

7:48 am-11:55 am

2 stops20h 07m

Belfast City

Wed 10/8

6:50 am-11:35 am

1 stop12h 45m

$741

SeattleBelfast

SEA - BHD

SEABHD

Seattle/Tacoma Intl

Wed 12/3

6:50 pm-7:10 pm

1 stop16h 20m

Belfast City

Sun 12/7

5:35 pm-4:55 pm

1 stop31h 20m

$743

SeattleBelfast

SEA - BFS

SEABFS

Seattle/Tacoma Intl

Wed 10/1

7:00 pm-8:35 pm

2 stops17h 35m

Belfast Intl

Wed 10/8

6:10 am-8:40 pm

2 stops22h 30m

$770

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/14

Best time to book a flight from Seattle to Belfast

Have a flexible travel schedule? Discover the best time to fly to Belfast from Seattle with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Seattle to Belfast

What is the cheapest time of day to fly from SEA to BFS?

Find hourly flight availability from Seattle to Belfast. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 15, 2025.

A simple way to save on the total cost of your ticket is to fly from Seattle to Belfast in the morning. If you’re flexible enough to do this you can expect to save up to 23% on your trip compared to booking a flight at noon.

Reviews of airlines servicing Belfast

Get insights into the airlines that provide service to Belfast. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Belfast. Reviews last updated September 15, 2025.
Read reviews from past customers who have flown British Airways from Seattle to Belfast. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
British Airways
6.7
Okay
7,361 reviews

Entertainment

6.4

Crew

7.6

Comfort

6.7

Overall

6.7

Food

6.3

Boarding

6.9

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2025

IAD - LHR

The plane had to load and unload passengers not through a jet way but out on the tarmac at Heathrow. The steps were steep. We weren't expecting to have to carry our luggage up and down stairs.
British Airways
6.7
Okay
7,361 reviews
British Airways
6.7
Okay
7,361 reviews

Entertainment

6.4

Crew

7.6

Comfort

6.7

Overall

6.7

Food

6.3

Boarding

6.9

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2025

IAD - LHR

The plane had to load and unload passengers not through a jet way but out on the tarmac at Heathrow. The steps were steep. We weren't expecting to have to carry our luggage up and down stairs.

Related info for your journey

Find useful and relevant information for your journey from Seattle to Belfast. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly from for flights from Seattle to Belfast?

    If you book a flight to Belfast from Seattle, you will be flying from Seattle/Tacoma Intl, which is the city’s only airport. Seattle/Tacoma Intl (SEA) is located 11.4 mi from the center of Seattle. There are 0 flights from Seattle/Tacoma Intl to Belfast per day from 1 airline.

  • How long is the flight from Seattle to Belfast?

    Airlines like Finnair fly from Seattle to Belfast in about 16h 40m. The time it takes to get you to your destination can typically vary by up to . The distance between Seattle and Belfast is about 4472 mi.

  • What is the cheapest airline to fly from Seattle to Belfast round-trip?

    Flying on British Airways is currently your cheapest option to Belfast, with prices starting at $737. British Airways is 20% cheaper than the average price of flights available within the next 90 days to this destination.

  • Can I find deals for flights from Seattle to Belfast that include hotel bookings?

    Yes. In addition to deals on Seattle to Belfast flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to Belfast?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Belfast.

  • Can I find deals for business class flights from Seattle to Belfast?

    Yes. Cheapflights offers flight deals from Seattle to Belfast by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Seattle to Belfast?

    Currently, February is the cheapest month in which you can book a flight from Seattle to Belfast (average of $657). Flying from Seattle to Belfast in June is currently the most expensive (average of $1,189). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Seattle to Belfast

See prices for flight routes from nearby airports that may be better suited for you.
Seattle to Belfast City flights
Portland to Belfast Intl flights
Portland to Belfast City flights

Top airline flying from Seattle to Belfast

Discover the top airline that operate flights from Seattle to Belfast. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated September 15, 2025.
AirlineCheapestAverageFlexibilityOn-time
British AirwaysCheapest$737Average$951FlexibilityNo cancel feeOn-time70%

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