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$231+ Cheap flights from Islip, NY to Seattle (ISP - SEA)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 6/19. Fares are subject to change and may not be available on all flights or dates of travel.
ISP — SEA
Apr 9 — Apr 161
Thu 4/9
Thu 4/16
1 adult, Economy
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Cheap flight deals from Islip to Seattle

Cheapest flights from Islip to Seattle
Explore the most affordable flight options available from Islip to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 10, 2026.

This Southwest deal was found by Cheapflights users on 3/6. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/315:25 pm
ISP
-
SEA
2 stops9h 45m
Southwest
Sat 6/69:25 pm
SEA
-
ISP
1 stop11h 20m
Southwest
Deal found 3/6$458
This Southwest deal was found by Cheapflights users on 3/6. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/304:40 pm
ISP
-
SEA
2 stops10h 50m
Southwest
Fri 7/310:45 pm
SEA
-
ISP
2 stops9h 50m
Southwest
Deal found 3/6$479
This Southwest deal was found by Cheapflights users on 3/5. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/2412:20 pm
ISP
-
SEA
2 stops15h 00m
Southwest
Sun 3/2911:55 pm
SEA
-
ISP
2 stops8h 45m
Southwest
Deal found 3/5$553
This Southwest deal was found by Cheapflights users on 3/9. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/66:10 am
ISP
-
SEA
2 stops10h 45m
Southwest
Sat 8/1510:30 pm
SEA
-
ISP
1 stop8h 25m
Southwest
Deal found 3/9$563
This Southwest deal was found by Cheapflights users on 3/5. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/2912:30 pm
ISP
-
SEA
1 stop9h 00m
Southwest
Thu 7/29:25 pm
SEA
-
ISP
1 stop7h 55m
Southwest
Deal found 3/5$567
This Southwest deal was found by Cheapflights users on 3/9. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/2412:20 pm
ISP
-
SEA
2 stops15h 00m
Southwest
Sat 3/2811:55 pm
SEA
-
ISP
2 stops14h 10m
Southwest
Deal found 3/9$583

Find flight deals from Islip to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from Islip (ISP) to Seattle (SEA). 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 March 10, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$458
(Southwest)

One-way from

$231
(Kiwi.com)

Popular in

December

Cheapest in

October

Average price

$382
Provider with most accurate pricing for Islip Long Island-Seattle/Tacoma Intl flight deals.
Search Deals
Provider most trusted by Cheapflights users for Islip Long Island-Seattle/Tacoma Intl flights.
Search Deals
From Islip Long Island to Seattle/Tacoma Intl
Search Deals
One-way flight from Islip Long Island to Seattle/Tacoma Intl
Search Deals
Highest demand for flights based on searches. 2% potential increase in price ($11 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($12 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in March 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Islip 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, Cheapflights users made 2,558,603 searches. Data last updated March 10, 2026.
Use the filters below to find and compare flights from Islip to Seattle that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Tue 6/30

4:40 pm-12:30 am

2 stops10h 50m

Seattle/Tacoma Intl

Fri 7/3

10:45 pm-11:35 am

2 stops9h 50m

$479

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Tue 3/24

12:20 pm-12:20 am

2 stops15h 00m

Seattle/Tacoma Intl

Sun 3/29

11:55 pm-11:40 am

2 stops8h 45m

$553
Quickest round-trip

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Thu 8/6

6:10 am-1:55 pm

2 stops10h 45m

Seattle/Tacoma Intl

Sat 8/15

10:30 pm-9:55 am

1 stop8h 25m

$563

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Tue 3/24

12:20 pm-12:20 am

2 stops15h 00m

Seattle/Tacoma Intl

Sat 3/28

11:55 pm-5:05 pm

2 stops14h 10m

$583

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Thu 5/21

8:35 am-8:25 pm

2 stops14h 50m

Seattle/Tacoma Intl

Tue 5/26

11:45 pm-1:50 pm

2 stops11h 05m

$607

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Mon 6/29

12:30 pm-9:50 pm

2 stops12h 20m

Seattle/Tacoma Intl

Thu 7/2

7:20 pm-8:20 am

2 stops10h 00m

$607
Cheapest one-way

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Fri 6/19

8:43 pm-3:39 pm

3 stops45h 56m

$321
Quickest one-way

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Fri 6/19

12:30 pm-6:30 pm

1 stop9h 00m

$374

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/5

Sorted by cheapest first

Compare providers for flights from Islip to Seattle

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Islip to Seattle in March.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Islip, New York-Seattle flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Islip, New York-Seattle flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Islip, New York-Seattle flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Islip, New York-Seattle flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Islip, New York-Seattle flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Islip to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Islip 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 Islip to Seattle

What is the cheapest month to book a flight from Islip, New York to Seattle?

Currently, October is the cheapest month in which you can book a flight from Islip, New York to Seattle (average of $148). Flying from Islip, New York to Seattle in April is currently the most expensive (average of $219). 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.

Related info for your journey

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

  • How long is the flight from Islip, New York to Seattle?

    Airlines like Southwest fly from Islip, New York to Seattle in about 9h 45m. The time it takes to get you to your destination can typically vary by up to . Islip, New York and Seattle are separated by a distance of 2440 mi.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Islip to Seattle 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 Islip, New York to Seattle?

    Currently, October is the cheapest month in which you can book a flight from Islip, New York to Seattle (average of $148). Flying from Islip, New York to Seattle in April is currently the most expensive (average of $219). 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

Traveling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
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Edmonds
Lacey
Renton
Puyallup
Kirkland
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