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$95+ Cheap flights from Islip, NY to Denver (ISP - DEN)

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 5/8. Fares are subject to change and may not be available on all flights or dates of travel.
ISP — DEN
Apr 9 — Apr 161
Thu 4/9
Thu 4/16
1 adult, Economy
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Cheap flight deals from Islip to Denver

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

This Priceline 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/14:07 pm
ISP
-
DEN
1 stop8h 52m
Frontier
Sun 5/311:59 pm
DEN
-
ISP
1 stop7h 14m
Frontier
Deal found 3/9$190
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/93:55 pm
ISP
-
DEN
1 stop9h 14m
Frontier
Thu 4/1611:59 pm
DEN
-
ISP
1 stop7h 14m
Frontier
Deal found 3/9$210
This Frontier deal was found by Cheapflights users on 3/8. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/84:07 pm
ISP
-
DEN
1 stop8h 52m
Frontier
Sat 5/911:59 pm
DEN
-
ISP
1 stop7h 14m
Frontier
Deal found 3/8$211
This Priceline 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/154:07 pm
ISP
-
DEN
1 stop8h 52m
Frontier
Sun 5/1711:59 pm
DEN
-
ISP
1 stop7h 14m
Frontier
Deal found 3/9$240
This Kiwi.com 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/44:07 pm
ISP
-
DEN
2 stops22h 02m
Frontier
Fri 5/811:59 pm
DEN
-
ISP
1 stop31h 14m
Frontier
Deal found 3/6$248
This Kiwi.com 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/42:31 pm
ISP
-
DEN
1 stop9h 13m
Multiple Airlines
Fri 5/811:59 pm
DEN
-
ISP
1 stop31h 14m
Multiple Airlines
Deal found 3/6$254
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 3/2810:43 am
ISP
-
DEN
1 stop14h 30m
Frontier
Wed 4/111:59 pm
DEN
-
ISP
1 stop13h 11m
Frontier
Deal found 3/6$260
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/114:07 pm
ISP
-
DEN
1 stop8h 52m
Frontier
Wed 5/1311:59 pm
DEN
-
ISP
1 stop7h 14m
Frontier
Deal found 3/6$261
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 3/2810:43 am
ISP
-
DEN
1 stop14h 30m
Frontier
Thu 4/211:59 pm
DEN
-
ISP
1 stop8h 57m
Frontier
Deal found 3/6$284
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 3/2810:43 am
ISP
-
DEN
1 stop14h 30m
Frontier
Fri 4/310:45 am
DEN
-
ISP
1 stop11h 09m
Frontier
Deal found 3/6$290

Find flight deals from Islip to Denver

Discover tips and strategies to find the most affordable flight options for your journey from Islip (ISP) to Denver (DEN). 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

$190
(Priceline)

One-way from

$95
(Frontier)

Popular in

March

Cheapest in

September

Average price

$936
Provider with most accurate pricing for Islip Long Island-Denver Intl flight deals.
Search Deals
Provider most trusted by Cheapflights users for Islip Long Island-Denver Intl flights.
Search Deals
From Islip Long Island to Denver Intl
Search Deals
One-way flight from Islip Long Island to Denver Intl
Search Deals
Highest demand for flights based on searches. 17% potential increase in price ($108 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 8% potential price decrease ($42 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 Denver 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 Denver that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Thu 4/9

3:55 pm-11:09 pm

1 stop9h 14m

Denver Intl

Thu 4/16

11:59 pm-9:13 am

1 stop7h 14m

$210

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Fri 5/8

4:07 pm-10:59 pm

1 stop8h 52m

Denver Intl

Sat 5/9

11:59 pm-9:13 am

1 stop7h 14m

$211

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Mon 5/18

4:30 pm-11:15 pm

2 stops8h 45m

Denver Intl

Wed 5/20

10:55 am-10:10 pm

2 stops9h 15m

$383
Quickest round-trip

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Sat 5/2

4:40 pm-9:35 pm

1 stop6h 55m

Denver Intl

Mon 5/4

7:35 am-4:30 pm

2 stops6h 55m

$384

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Wed 4/29

4:10 pm-9:30 pm

1 stop7h 20m

Denver Intl

Sun 5/3

11:50 pm-12:05 pm

1 stop10h 15m

$407

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Fri 5/22

4:30 pm-11:45 pm

2 stops9h 15m

Denver Intl

Wed 5/27

5:15 am-1:50 pm

1 stop6h 35m

$418

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Thu 4/9

4:30 pm-9:30 pm

1 stop7h 00m

Denver Intl

Sun 4/12

11:55 pm-11:50 am

1 stop9h 55m

$418

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Fri 5/22

4:30 pm-11:45 pm

2 stops9h 15m

Denver Intl

Tue 5/26

11:55 pm-1:50 pm

1 stop11h 55m

$418

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Thu 4/16

4:30 pm-11:25 pm

2 stops8h 55m

Denver Intl

Mon 4/20

11:35 am-8:25 pm

2 stops6h 50m

$419

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Mon 5/4

4:30 pm-11:15 pm

2 stops8h 45m

Denver Intl

Fri 5/8

11:35 am-8:25 pm

2 stops6h 50m

$419

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/7

Showing 1-10 of 18 resultsSorted by cheapest first
1
2

Compare providers for flights from Islip to Denver

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 Denver 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-Denver 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-Denver flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Islip, New York-Denver flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Islip, New York-Denver 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-Denver 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 Denver

Have a flexible travel schedule? Discover the best time to fly to Denver 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 Denver

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

Currently, January is the cheapest month in which you can book a flight from Islip, New York to Denver (average of $85). Flying from Islip, New York to Denver in June is currently the most expensive (average of $139). 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 Denver

Get insights into the airlines that provide service to Denver. 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 Denver. Reviews last updated March 10, 2026.
Peruse reviews from past customers who have flown with Southwest from Islip to Denver to help guide your decision. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,317 reviews

Crew

8.6

Entertainment

7.5

Comfort

8.0

Boarding

8.1

Food

7.0

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Mar 2026

KOA - HNL

pretty smooth and fast service ever, that flight is very helpful each and everyone for price and also fright for free..
Southwest
8.0
Very good
4,317 reviews
Southwest
8.0
Very good
4,317 reviews

Crew

8.6

Entertainment

7.5

Comfort

8.0

Boarding

8.1

Food

7.0

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Mar 2026

KOA - HNL

pretty smooth and fast service ever, that flight is very helpful each and everyone for price and also fright for free..

Related info for your journey

Find useful and relevant information for your journey from Islip to Denver. 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 Denver?

    Frontier and Southwest can get you from Islip, New York to Denver in just under 8h 45m. Your travel time can differ by up to 29m. The distance between Islip, New York and Denver is about 1654 mi. Both multi-stop and nonstop flights can be found to your destination and back.

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

    Southwest, at $377, was found to be the cheapest airline from Islip, New York to Denver.. This flight start at 27% lower than the current average price 3 months from now.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Islip to Denver 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 Denver?

    Currently, January is the cheapest month in which you can book a flight from Islip, New York to Denver (average of $85). Flying from Islip, New York to Denver in June is currently the most expensive (average of $139). 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 Denver?

Book flights to Denver if you plan to visit one of these locations
Thornton
Black Hawk
Lakewood
Broomfield
Westminster
Golden
Centennial
Greeley
Lone Tree
Wheat Ridge
Silverthorne
Central City
Cripple Creek
Winter Park
Glendale
Manitou Springs
Frisco
Fort Morgan
Brighton
Evergreen

Browse thousands of different options on Cheapflights for your next trip

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Top airline flying from Islip to Denver

Discover the top airline that operate flights from Islip to Denver. 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 March 10, 2026.
AirlineCheapestAverageFlexibilityOn-time
SouthwestCheapest$377Average$521FlexibilityNo cancel feeOn-time63%

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