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$392+ Cheap flights from Islip 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 9/24. Fares are subject to change and may not be available on all flights or dates of travel.
ISP — SEA
Oct 11 — Oct 181
Sat 10/11
Sat 10/18
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 September 11, 2025.

Round-trip from

$493
(Southwest)

One-way from

$392
(Cheapflightsfares)

Popular in

December

Cheapest in

September

Average price

$322
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. 6% potential increase in price ($26 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($14 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 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 September 11, 2025.

This Southwest deal was found by Cheapflights users on 9/10. 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 12/255:40 amISP - SEA
2 stops10h 45mSouthwest
Thu 1/16:15 amSEA - ISP
2 stops12h 50mSouthwest
Deal found 9/10$493
This Southwest deal was found by Cheapflights users on 9/9. 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.
Mon 9/293:05 pmISP - SEA
1 stop9h 25mSouthwest
Tue 10/76:55 amSEA - ISP
2 stops12h 10mSouthwest
Deal found 9/9$522
This Cheapflightsfares deal was found by Cheapflights users on 9/10. 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.
Sat 9/204:33 pmISP - SEA
1 stop8h 35mMultiple Airlines
Sun 9/2811:34 pmSEA - ISP
1 stop8h 24mMultiple Airlines
Deal found 9/10$673
This Cheapflightsfares deal was found by Cheapflights users on 9/10. 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.
Sat 9/204:33 pmISP - SEA
1 stop8h 35mMultiple Airlines
Mon 9/2211:34 pmSEA - ISP
1 stop8h 24mMultiple Airlines
Deal found 9/10$675
This Cheapflightsfares deal was found by Cheapflights users on 9/10. 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.
Sat 9/134:33 pmISP - SEA
1 stop8h 35mMultiple Airlines
Sat 9/208:00 amSEA - ISP
1 stop9h 01mMultiple Airlines
Deal found 9/10$692
This Cheapflightsfares deal was found by Cheapflights users on 9/10. 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.
Sat 9/204:33 pmISP - SEA
1 stop8h 35mMultiple Airlines
Sat 9/278:00 amSEA - ISP
1 stop9h 01mMultiple Airlines
Deal found 9/10$709
This Cheapflightsfares deal was found by Cheapflights users on 9/9. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/134:33 pmISP - SEA
1 stop8h 35mMultiple Airlines
Sat 9/278:00 amSEA - ISP
1 stop9h 01mMultiple Airlines
Deal found 9/9$718
This Cheapflightsfares deal was found by Cheapflights users on 9/10. 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.
Mon 9/154:33 pmISP - SEA
1 stop8h 35mMultiple Airlines
Sat 9/208:00 amSEA - ISP
1 stop9h 01mMultiple Airlines
Deal found 9/10$745
This Cheapflightsfares deal was found by Cheapflights users on 9/9. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/134:33 pmISP - SEA
1 stop8h 35mMultiple Airlines
Fri 9/2611:34 pmSEA - ISP
1 stop8h 24mMultiple Airlines
Deal found 9/9$755
This Cheapflightsfares deal was found by Cheapflights users on 9/9. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/134:33 pmISP - SEA
1 stop8h 35mMultiple Airlines
Fri 9/1911:34 pmSEA - ISP
1 stop8h 24mMultiple Airlines
Deal found 9/9$759
This Cheapflightsfares deal was found by Cheapflights users on 9/9. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/124:33 pmISP - SEA
1 stop8h 35mMultiple Airlines
Sun 9/1411:34 pmSEA - ISP
1 stop8h 24mMultiple Airlines
Deal found 9/9$766

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 September 11, 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

Thu 12/25

5:40 am-1:25 pm

2 stops10h 45m

Seattle/Tacoma Intl

Thu 1/1

6:15 am-10:05 pm

2 stops12h 50m

$493

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Mon 9/29

3:05 pm-9:30 pm

1 stop9h 25m

Seattle/Tacoma Intl

Tue 10/7

6:55 am-10:05 pm

2 stops12h 10m

$522

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Fri 12/5

2:19 pm-10:43 pm

2 stops11h 24m

Seattle/Tacoma Intl

Sun 12/7

11:21 pm-10:58 am

1 stop8h 37m

$821

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Thu 12/4

2:19 pm-10:43 pm

2 stops11h 24m

Seattle/Tacoma Intl

Mon 12/8

11:21 pm-10:58 am

1 stop8h 37m

$845

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Fri 10/3

4:33 pm-10:08 pm

1 stop8h 35m

Seattle/Tacoma Intl

Mon 10/6

11:15 pm-10:58 am

1 stop8h 43m

$873

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Wed 10/1

4:33 pm-10:08 pm

1 stop8h 35m

Seattle/Tacoma Intl

Fri 11/14

9:00 am-8:01 pm

1 stop8h 01m

$917

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Fri 10/3

4:33 pm-10:08 pm

1 stop8h 35m

Seattle/Tacoma Intl

Sun 10/5

8:30 am-8:01 pm

1 stop8h 31m

$917

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Tue 9/23

4:33 pm-10:08 pm

1 stop8h 35m

Seattle/Tacoma Intl

Tue 9/30

11:34 pm-10:58 am

1 stop8h 24m

$924

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Thu 12/25

2:19 pm-11:15 pm

2 stops11h 56m

Seattle/Tacoma Intl

Tue 12/30

11:25 pm-10:58 am

1 stop8h 33m

$987

IslipSeattle

ISP - SEA

ISPSEA

Islip Long Island

Tue 9/30

4:33 pm-10:08 pm

1 stop8h 35m

Seattle/Tacoma Intl

Sun 10/5

11:15 pm-10:58 am

1 stop8h 43m

$997

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/10

Showing 1-10 of 20 results
1
2

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 to Seattle?

Currently, January is the cheapest month in which you can book a flight from Islip to Seattle (average of $238). Flying from Islip to Seattle in June is currently the most expensive (average of $388). 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 September 11, 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
4,248 reviews

Entertainment

7.5

Food

7.0

Overall

8.0

Comfort

8.0

Boarding

8.1

Crew

8.6

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
4,248 reviews
Southwest
8.0
Very good
4,248 reviews

Entertainment

7.5

Food

7.0

Overall

8.0

Comfort

8.0

Boarding

8.1

Crew

8.6

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 to Seattle?

    Departing from Islip to Seattle will take you 10h 45m. The distance from Islip to Seattle is about 2440 mi.

  • What is the cheapest airline to fly from Islip 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 to Seattle?

    Currently, January is the cheapest month in which you can book a flight from Islip to Seattle (average of $238). Flying from Islip to Seattle in June is currently the most expensive (average of $388). 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
Ocean Shores
Lynnwood
Edmonds
Leavenworth
Lacey
Renton
Olympia
Kent
Federal Way
Cle Elum
Puyallup
Chehalis
Kirkland
Issaquah
Aberdeen
Shoreline

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Islip to Seattle

See prices for flight routes from nearby airports that may be better suited for you.
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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 September 11, 2025.
AirlineCheapestAverageFlexibilityOn-time
SouthwestCheapest$356Average$541FlexibilityNo cancel feeOn-time63%

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