HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Denver

$168+ 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 9/8. Fares are subject to change and may not be available on all flights or dates of travel.
ISP — DEN
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Islip to Denver with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap 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 June 12, 2025.

Round-trip from

$302
(Southwest)

One-way from

$168
(Cheapflightsfares)

Popular in

April

Cheapest in

December

Average price

$496
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. 24% potential increase in price ($146 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($18 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 2025
Search Deals

Find 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 June 12, 2025.

This Southwest deal was found by Cheapflights users on 6/10. 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.
Mon 12/85:40 amISP - DEN
2 stops10h 15mSouthwest
Thu 12/117:00 amDEN - ISP
1 stop6h 20mSouthwest
Deal found 6/10$302
This Frontier deal was found by Cheapflights users on 6/12. 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 6/132:05 pmISP - DEN
1 stop11h 54mFrontier
Sun 6/1511:58 pmDEN - ISP
1 stop11h 08mFrontier
Deal found 6/12$318

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 June 12, 2025.
Use the filters below to find and compare flights from Islip to Denver that are best for you.

Fly from

Islip

Fly to

Denver

Route

Depart

Return

Price

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Thu 8/14

2:05 pm-11:56 pm

1 stop11h 51m

Denver Intl

Wed 8/20

11:59 pm-12:09 pm

1 stop10h 10m

$340

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Tue 8/12

5:30 am-5:55 pm

1 stop14h 25m

Denver Intl

Sat 8/23

11:50 am-9:40 pm

1 stop7h 50m

$348

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Mon 9/8

5:05 pm-11:16 pm

1 stop8h 11m

$168

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Wed 8/13

4:00 pm-8:00 pm

1 stop6h 00m

$214

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Fri 7/11

10:36 am-10:59 pm

2 stops38h 23m

$441

IslipDenver

ISP - DEN

ISPDEN

Islip Long Island

Wed 8/13

2:19 pm-8:58 am

3 stops20h 39m

$701

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/12

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, October is the cheapest month in which you can book a flight from Islip, New York to Denver (average of $197). Flying from Islip, New York to Denver in March is currently the most expensive (average of $278). 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.

What is the cheapest time of day to fly from ISP to DEN?

Find hourly flight availability from Islip to Denver. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 12, 2025.

It’s typically best to fly out from Islip, New York to Denver in the afternoon. Doing so could potentially save you 45% on the flight price compared to flying at noon, which is usually more expensive.

Rainfall in Denver by month

Plan your trip to Denver by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Denver ranges from 0.5 - 2.3 inches per month. May is typically the wettest month, when rainfall can reach 2.3 in. January is typically the driest time to visit Denver when rainfall is around 0.5 in.

Temperature in Denver by month

Plan your trip to Denver by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Denver, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 30.2 F).

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 June 12, 2025.
Breeze Airways
8.1
Very good
178 reviews

Entertainment

6.6

Crew

8.8

Overall

8.1

Comfort

8.2

Boarding

8.3

Food

6.7

Reviews

1 / 11
10.0
Excellent

Dena,Dec 2024

LAS - BDL

It was comfortable and the crew was great! A few free snacks offered would be nice!
Breeze Airways
8.1
Very good
178 reviews
Breeze Airways
8.1
Very good
178 reviews

Entertainment

6.6

Crew

8.8

Overall

8.1

Comfort

8.2

Boarding

8.3

Food

6.7

Reviews

1 / 11
10.0
Excellent

Dena,Dec 2024

LAS - BDL

It was comfortable and the crew was great! A few free snacks offered would be nice!
Southwest
8.0
Very good
4,287 reviews
Breeze Airways
8.1
Very good
178 reviews

Entertainment

6.6

Crew

8.8

Overall

8.1

Comfort

8.2

Boarding

8.3

Food

6.7

Reviews

1 / 11
10.0
Excellent

Dena,Dec 2024

LAS - BDL

It was comfortable and the crew was great! A few free snacks offered would be nice!
Frontier
5.9
Fair
3,295 reviews
Breeze Airways
8.1
Very good
178 reviews

Entertainment

6.6

Crew

8.8

Overall

8.1

Comfort

8.2

Boarding

8.3

Food

6.7

Reviews

1 / 11
10.0
Excellent

Dena,Dec 2024

LAS - BDL

It was comfortable and the crew was great! A few free snacks offered would be nice!

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.

  • What are the cheapest airlines flying from Islip, New York to Denver round-trip?

    Southwest, at $302, was found to be the cheapest airline from Islip, New York to Denver. An alternate airline flying to your destination would be Frontier. These flights start at 31% lower than the current average price 3 months from now.

  • What are the cheapest airlines to fly from Islip, New York to Denver one-way?

    One-way options have recently been found by users for as low as $168 on Frontier. Other airlines that offer cheap prices include Southwest from $186 and Breeze Airways from $441 one-way.

  • 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, October is the cheapest month in which you can book a flight from Islip, New York to Denver (average of $197). Flying from Islip, New York to Denver in March is currently the most expensive (average of $278). 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 Islip?

Book flights to Islip if you plan to visit one of these locations
Westminster
Black Hawk
Winter Park
Lakewood
Cripple Creek
Golden
Brighton
Silverthorne
Thornton
Frisco
Grand Lake
Broomfield
Central City
Glendale
Copper Mountain
Wheat Ridge
Longmont
Idaho Springs
Greeley
Limon

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Islip to Denver

See prices for flight routes from nearby airports that may be better suited for you.
LaGuardia to Denver flights
John F Kennedy Intl to Denver flights
Newark to Denver flights
Syracuse to Denver flights
Buffalo to Denver flights
Albany to Denver flights
John F Kennedy Intl to Aspen flights
Rochester to Denver flights
Newark to Aspen flights
LaGuardia to Aspen flights
John F Kennedy Intl to Colorado Springs flights
LaGuardia to Colorado Springs flights
Newark to Colorado Springs flights
John F Kennedy Intl to Grand Junction flights
Newark to Vail flights
Newark to Grand Junction flights
LaGuardia to Grand Junction flights
Newark to Montrose flights
LaGuardia to Vail flights
Ithaca to Denver flights
White Plains to Denver flights
LaGuardia to Montrose flights
John F Kennedy Intl to Vail flights
LaGuardia to Durango flights
Newark to Durango flights
Binghamton to Denver flights
Newark to Hayden flights
Stewart to Denver flights
John F Kennedy Intl to Montrose flights
Newark to Gunnison flights
LaGuardia to Gunnison flights
John F Kennedy Intl to Durango flights
LaGuardia to Hayden flights
Rochester to Colorado Springs flights
Elmira to Denver flights
Albany to Colorado Springs flights
White Plains to Colorado Springs flights
Buffalo to Aspen flights
Syracuse to Montrose flights
Syracuse to Colorado Springs flights
Buffalo to Colorado Springs flights
Buffalo to Hayden flights
White Plains to Aspen flights
Syracuse to Hayden flights
Rutland to Denver flights
Albany to Montrose flights
Albany to Aspen flights
Rochester to Grand Junction flights
Rochester to Aspen flights

Top 2 airlines flying from Islip to Denver

Discover the top 2 airlines 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 June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$148Average$263FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$417Average$521FlexibilityNo cancel feeOn-time63%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.