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Cheap flights from Northern Ireland to Seattle from £325

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Northern Ireland to Seattle departing on 31/8. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
1 adult, Economy, 0 bags

Find the cheapest flights from Northern Ireland to Seattle

Cheap return flights

Enter your travel dates to find the best prices.
Multiple Airlines Logo
08:20 - 20:40BFS  Belfast Intl-SEA Seattle/Tacoma Intl
20h 20m2 stops London Gatwick Reykjavik Keflavik Intl
Multiple Airlines Logo
19:00 - 21:05SEA  Seattle/Tacoma Intl-BFS Belfast Intl
18h 05m2 stops Reykjavik Keflavik Intl London Gatwick
£576Multiple Airlines
Tue, 29 Sep - Tue, 6 Oct
Multiple Airlines Logo
21:10 - 09:40BFS  Belfast Intl-SEA Seattle/Tacoma Intl
44h 30m3 stops London Gatwick Toronto Pearson Intl Calgary
Multiple Airlines Logo
15:40 - 21:00SEA  Seattle/Tacoma Intl-BFS Belfast Intl
21h 20m2 stops Reykjavik Keflavik Intl Glasgow Intl
£654Multiple Airlines
Sun, 27 Sep - Sun, 4 Oct
Multiple Airlines Logo
21:10 - 09:40BFS  Belfast Intl-SEA Seattle/Tacoma Intl
44h 30m3 stops London Gatwick Toronto Pearson Intl Calgary
Multiple Airlines Logo
15:40 - 20:55SEA  Seattle/Tacoma Intl-BFS Belfast Intl
21h 15m3 stops Reykjavik Keflavik Intl Kastrup Copenhagen Edinburgh Turnhouse
£666Multiple Airlines
Sun, 27 Sep - Sun, 4 Oct
Multiple Airlines Logo
21:15 - 18:45BFS  Belfast Intl-SEA Seattle/Tacoma Intl
29h 30m3 stops Glasgow Intl Toronto Pearson Intl Calgary
Multiple Airlines Logo
19:00 - 21:20SEA  Seattle/Tacoma Intl-BFS Belfast Intl
18h 20m3 stops Reykjavik Keflavik Intl Kastrup Copenhagen Manchester
£669Multiple Airlines
Tue, 29 Sep - Tue, 6 Oct
Multiple Airlines Logo
21:15 - 18:45BFS  Belfast Intl-SEA Seattle/Tacoma Intl
29h 30m3 stops Glasgow Intl Toronto Pearson Intl Calgary
Multiple Airlines Logo
19:00 - 21:05SEA  Seattle/Tacoma Intl-BFS Belfast Intl
18h 05m2 stops Reykjavik Keflavik Intl London Gatwick
£672Multiple Airlines
Tue, 29 Sep - Tue, 6 Oct
Multiple Airlines Logo
07:10 - 13:45BFS  Belfast Intl-SEA Seattle/Tacoma Intl
14h 35m2 stops Manchester Kastrup Copenhagen
Multiple Airlines Logo
15:55 - 21:30SEA  Seattle/Tacoma Intl-BFS Belfast Intl
21h 35m2 stops Kastrup Copenhagen Manchester
£711Multiple Airlines
Sun, 27 Sep - Sun, 4 Oct
British Airways Logo
07:40 - 16:50BHD  Belfast City-SEA Seattle/Tacoma Intl
17h 10m1 stop London Heathrow
British Airways Logo
06:12 - 14:15SEA  Seattle/Tacoma Intl-BHD Belfast City
24h 03m2 stops Chicago O'Hare Intl London Heathrow
£721British Airways
Thu, 5 Nov - Mon, 9 Nov
British Airways Logo
11:35 - 11:35BHD  Belfast City-SEA Seattle/Tacoma Intl
32h 00m1 stop London Heathrow
British Airways Logo
20:20 - 20:35SEA  Seattle/Tacoma Intl-BHD Belfast City
16h 15m1 stop London Heathrow
£722British Airways
Wed, 7 Oct - Sun, 11 Oct
British Airways Logo
06:30 - 11:25BHD  Belfast City-SEA Seattle/Tacoma Intl
12h 55m1 stop London Heathrow
British Airways Logo
10:41 - 16:05SEA  Seattle/Tacoma Intl-BHD Belfast City
21h 24m2 stops Chicago O'Hare Intl London Heathrow
£722British Airways
Thu, 5 Nov - Mon, 9 Nov
British Airways Logo
11:35 - 00:36BHD  Belfast City-SEA Seattle/Tacoma Intl
21h 01m2 stops London Heathrow Chicago O'Hare Intl
British Airways Logo
06:12 - 14:35SEA  Seattle/Tacoma Intl-BHD Belfast City
24h 23m2 stops Chicago O'Hare Intl London Heathrow
£725British Airways
Wed, 7 Oct - Sun, 11 Oct

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Aer Lingus flights from Northern Ireland to Seattle

Our best Aer Lingus deals on Northern Ireland to Seattle flight tickets
Aer Lingus
20 Aug
BHD18:30Belfast City
30h 40m
2 stops
SEA17:10Seattle/Tacoma Intl
24 Aug
SEA19:10Seattle/Tacoma Intl
17h 40m
2 stops
BHD20:50Belfast City
£3,283
Aer Lingus
20 Aug
BHD09:50Belfast City
15h 20m
2 stops
SEA17:10Seattle/Tacoma Intl
24 Aug
SEA19:10Seattle/Tacoma Intl
14h 50m
2 stops
BHD18:00Belfast City
£3,287
Aer Lingus
20 Aug
BHD09:50Belfast City
15h 20m
2 stops
SEA17:10Seattle/Tacoma Intl
24 Aug
SEA19:10Seattle/Tacoma Intl
14h 50m
2 stops
BHD18:00Belfast City
£3,288

KLM flights from Northern Ireland to Seattle

Our best KLM deals on Northern Ireland to Seattle flight tickets
KLM
19 Aug
BHD17:30Belfast City
26h 07m
1 stop
SEA11:37Seattle/Tacoma Intl
24 Aug
SEA17:45Seattle/Tacoma Intl
15h 10m
1 stop
BHD16:55Belfast City
£5,866
KLM
19 Aug
BHD17:30Belfast City
26h 07m
1 stop
SEA11:37Seattle/Tacoma Intl
24 Aug
SEA17:45Seattle/Tacoma Intl
15h 10m
1 stop
BHD16:55Belfast City
£5,881
KLM
19 Aug
BHD17:30Belfast City
26h 07m
1 stop
SEA11:37Seattle/Tacoma Intl
24 Aug
SEA17:45Seattle/Tacoma Intl
15h 10m
1 stop
BHD16:55Belfast City
£5,883

momondo Fare Finder

 
Customise your flight search to find flights from Northern Ireland to Seattle 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, momondo users made 279,928 searches. Data last updated 15 August 2026.
Use the filters below to find and compare flights from Northern Ireland to Seattle that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

BelfastSeattle

BFS Belfast Intl - SEA Seattle/Tacoma Intl

BFSSEA

Belfast Intl

Tue 29/9

08:20-20:40

2 stops20h 20m

Seattle/Tacoma Intl

Tue 6/10

19:00-21:05

2 stops18h 05m

£576

BelfastSeattle

BFS Belfast Intl - SEA Seattle/Tacoma Intl

BFSSEA

Belfast Intl

Sun 27/9

21:10-09:40

3 stops44h 30m

Seattle/Tacoma Intl

Sun 4/10

15:40-21:00

2 stops21h 20m

£654

BelfastSeattle

BFS Belfast Intl - SEA Seattle/Tacoma Intl

BFSSEA

Belfast Intl

Sun 27/9

21:10-09:40

3 stops44h 30m

Seattle/Tacoma Intl

Sun 4/10

15:40-20:55

3 stops21h 15m

£666

BelfastSeattle

BFS Belfast Intl - SEA Seattle/Tacoma Intl

BFSSEA

Belfast Intl

Tue 29/9

21:15-18:45

3 stops29h 30m

Seattle/Tacoma Intl

Tue 6/10

19:00-21:20

3 stops18h 20m

£669

BelfastSeattle

BFS Belfast Intl - SEA Seattle/Tacoma Intl

BFSSEA

Belfast Intl

Tue 29/9

21:15-18:45

3 stops29h 30m

Seattle/Tacoma Intl

Tue 6/10

19:00-21:05

2 stops18h 05m

£672

BelfastSeattle

BFS Belfast Intl - SEA Seattle/Tacoma Intl

BFSSEA

Belfast Intl

Sun 27/9

07:10-13:45

2 stops14h 35m

Seattle/Tacoma Intl

Sun 4/10

15:55-21:30

2 stops21h 35m

£711

BelfastSeattle

BHD Belfast City - SEA Seattle/Tacoma Intl

BHDSEA

Belfast City

Thu 5/11

07:40-16:50

1 stop17h 10m

Seattle/Tacoma Intl

Mon 9/11

06:12-14:15

2 stops24h 03m

£721

BelfastSeattle

BHD Belfast City - SEA Seattle/Tacoma Intl

BHDSEA

Belfast City

Wed 7/10

11:35-11:35

1 stop32h 00m

Seattle/Tacoma Intl

Sun 11/10

20:20-20:35

1 stop16h 15m

£722
Fastest return journey

BelfastSeattle

BHD Belfast City - SEA Seattle/Tacoma Intl

BHDSEA

Belfast City

Thu 5/11

06:30-11:25

1 stop12h 55m

Seattle/Tacoma Intl

Mon 9/11

10:41-16:05

2 stops21h 24m

£722

BelfastSeattle

BHD Belfast City - SEA Seattle/Tacoma Intl

BHDSEA

Belfast City

Wed 7/10

11:35-00:36

2 stops21h 01m

Seattle/Tacoma Intl

Sun 11/10

06:12-14:35

2 stops24h 23m

£725

Flights are sorted by cheapest return flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to Seattle from

How to get the cheapest flight ticket from Northern Ireland to Seattle

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest airline that flies from Northern Ireland to Seattle/Tacoma Intl?

Aer Lingus is the most popular carrier operating from Northern Ireland to Seattle/Tacoma Intl

Cheap Northern Ireland to Seattle flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Northern Ireland to Seattle

Fastest flight time

12h 55m

Direct flights

None
The fastest flight from Northern Ireland to Seattle takes 12h 55m
There are no direct flights from Northern Ireland to Seattle. There are no popular flight routes from Northern Ireland to Seattle.
Search flight deals

Frequently asked questions about flying from Northern Ireland to Seattle

  • When did momondo last update prices for flights from Northern Ireland to Seattle/Tacoma Intl Airport?

    Prices for flights from Northern Ireland to Seattle/Tacoma Intl Airport refresh daily.

  • How old do you have to be to fly from Northern Ireland to Seattle/Tacoma Intl Airport?

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Northern Ireland to Seattle/Tacoma Intl Airport.

  • What documentation or ID do you need to fly to Seattle/Tacoma Intl Airport?

    The travel and health documents required for your trip to Seattle/Tacoma Intl Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Seattle/Tacoma Intl Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

Travelling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
Westport
Kirkland
Ashford
Tacoma
SeaTac
Tukwila
Fife

Why use momondo?

Why should I use momondo to find a flight deal from Northern Ireland to Seattle?

momondo collates all your flight options in one place and lets you filter them to find the perfect flight from Northern Ireland to Seattle. momondo saves you time and could save you money on your trip.

Can I find flights from Northern Ireland to Seattle with flexible booking policies on momondo?

momondo does allow users to show only those flights to Seattle from Northern Ireland which offer a flexible booking policy as well as other useful filters and features.

How can momondo help me find flights from Northern Ireland to Seattle?

momondo helps you find the best flight between Northern Ireland and Seattle by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.

I’m not ready to book a flight from Northern Ireland to Seattle right now. Can momondo alert me if prices change?

Price alerts on flights to Seattle from Northern Ireland are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.

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