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$448+ 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 3/23. Fares are subject to change and may not be available on all flights or dates of travel.
ISP — SEA
Nov 27 — Dec 41
Thu 11/27
Thu 12/4
1 adult, Economy
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Cheap 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 October 28, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$529
(Southwest)

One-way from

$448
(Cheapflightsfares)

Popular in

December

Cheapest in

September

Average price

$319
Provider with most accurate pricing for Islip Long Island-Seattle/Tacoma Intl flight deals.
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Provider most trusted by Cheapflights users for Islip Long Island-Seattle/Tacoma Intl flights.
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From Islip Long Island to Seattle/Tacoma Intl
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One-way flight from Islip Long Island to Seattle/Tacoma Intl
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Highest demand for flights based on searches. 7% potential increase in price ($32 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($15 potential savings vs. average RT price).
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Average for round-trip flights in October 2025
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Find 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 October 28, 2025.

This Southwest deal was found by Cheapflights users on 10/27. 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 11/243:25 pmISP - SEA
2 stops12h 10mSouthwest
Mon 12/15:00 amSEA - ISP
2 stops15h 10mSouthwest
Deal found 10/27$529
This Kiwi.com deal was found by Cheapflights users on 10/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/1112:40 pmISP - SEA
1 stop24h 55mMultiple Airlines
Sat 11/159:00 amSEA - ISP
1 stop7h 45mMultiple Airlines
Deal found 10/27$1,015
This Kiwi.com deal was found by Cheapflights users on 10/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/249:02 amISP - SEA
2 stops37h 15mMultiple Airlines
Mon 12/111:12 pmSEA - ISP
1 stop8h 52mMultiple Airlines
Deal found 10/27$1,228

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 October 28, 2025.
Use the filters below to find and compare flights from Islip to Seattle that are best for you.

Fly from

Islip

Fly to

Seattle

Route

Depart

Return

Price

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Mon 11/24

3:25 pm-12:35 am

2 stops12h 10m

Seattle/Tacoma Intl

Mon 12/1

5:00 am-11:10 pm

2 stops15h 10m

$529

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Tue 2/24

7:30 am-1:23 pm

1 stop8h 53m

Seattle/Tacoma Intl

Fri 2/27

8:20 am-7:45 pm

1 stop8h 25m

$895

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Wed 2/25

7:30 am-1:23 pm

1 stop8h 53m

Seattle/Tacoma Intl

Fri 2/27

8:20 am-7:45 pm

1 stop8h 25m

$895

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Tue 2/17

7:30 am-1:23 pm

1 stop8h 53m

Seattle/Tacoma Intl

Thu 3/5

8:20 am-7:45 pm

1 stop8h 25m

$920

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Sun 3/8

7:30 am-1:23 pm

1 stop8h 53m

Seattle/Tacoma Intl

Thu 3/12

8:20 am-7:45 pm

1 stop8h 25m

$994

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Thu 2/12

7:30 am-1:23 pm

1 stop8h 53m

Seattle/Tacoma Intl

Sun 2/15

8:20 am-7:45 pm

1 stop8h 25m

$1,024

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Tue 2/17

7:30 am-1:23 pm

1 stop8h 53m

Seattle/Tacoma Intl

Sat 2/21

8:20 am-7:45 pm

1 stop8h 25m

$1,048

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Tue 11/11

10:38 am-7:05 pm

2 stops35h 27m

Seattle/Tacoma Intl

Sat 11/15

9:00 am-7:45 pm

1 stop7h 45m

$1,081

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Thu 2/19

7:30 am-1:23 pm

1 stop8h 53m

Seattle/Tacoma Intl

Sun 2/22

8:20 am-7:45 pm

1 stop8h 25m

$1,088

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Mon 2/16

7:30 am-1:23 pm

1 stop8h 53m

Seattle/Tacoma Intl

Fri 2/20

8:20 am-7:45 pm

1 stop8h 25m

$1,098

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/28

Showing 1-10 of 15 results
1
2

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 October.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice 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 eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on Islip, New York-Seattle flight deals on Cheapflights vs. eDreams >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 eDreams the most. eDreams 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 $140). Flying from Islip, New York to Seattle in December is currently the most expensive (average of $248). 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.

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. 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 Seattle. Reviews last updated October 28, 2025.
Read through reviews of airlines operating flights from Islip to Seattle, such as Southwest. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,240 reviews

Overall

8.0

Food

7.0

Entertainment

7.5

Comfort

8.0

Crew

8.6

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Southwest
8.0
Very good
4,240 reviews
Southwest
8.0
Very good
4,240 reviews

Overall

8.0

Food

7.0

Entertainment

7.5

Comfort

8.0

Crew

8.6

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

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 12h 10m. 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.

  • What is the cheapest airline to fly from Islip, New York to Seattle round-trip?

    Flying on Southwest is currently your cheapest option to Seattle, with prices starting at $356.

  • 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 $140). Flying from Islip, New York to Seattle in December is currently the most expensive (average of $248). 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
SeaTac
Tukwila
Tacoma
Lakewood
Olympia
Ocean Shores
Lynnwood
Edmonds
Leavenworth
Renton
Kirkland
Lacey
Kent
Federal Way
Cle Elum
Marysville
Puyallup
Chehalis
Fife
Issaquah

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Alternative routes for Islip to Seattle

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Top airline flying from Islip to Seattle

Discover the top airline that operate flights from Islip to Seattle. 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 October 28, 2025.
AirlineCheapestAverageFlexibilityOn-time
SouthwestCheapest$356Average$564FlexibilityNo cancel feeOn-time63%

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