$146 Cheap Flights from Islip (ISP) to Denver (DEN)

View $146 flight on Wed, Jun 17, 2026Opens in a new window

Popular airlines from MacArthur Airport (ISP) to Denver Intl. Airport (DEN)

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Cheap Flights from Islip to Denver (ISP-DEN)

Prices were available within the past 7 days and start at $146 for one-way flights and $280 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Wed, Jun 10 - Fri, Jun 12
ISP
Islip
DEN
Denver
$280 Roundtrip, found 6 days ago
$280
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Wed, Jun 10 from Islip to Denver, returning Fri, Jun 12, priced at $280 found 6 days ago
Frontier Airlines
Wed, May 27 - Wed, Jun 3
ISP
Islip
DEN
Denver
$285 Roundtrip, found 6 days ago
$285
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Wed, May 27 from Islip to Denver, returning Wed, Jun 3, priced at $285 found 6 days ago
Frontier Airlines
Tue, Jun 16 - Mon, Jun 22
ISP
Islip
DEN
Denver
$289 Roundtrip, found 23 hours ago
$289
Roundtrip
found 23 hours ago
Select Frontier Airlines flight, departing Tue, Jun 16 from Islip to Denver, returning Mon, Jun 22, priced at $289 found 23 hours ago
Frontier Airlines
Tue, Jun 16 - Fri, Jun 19
ISP
Islip
DEN
Denver
$290 Roundtrip, found 1 day ago
$290
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Tue, Jun 16 from Islip to Denver, returning Fri, Jun 19, priced at $290 found 1 day ago
Frontier Airlines
Wed, Jun 10 - Tue, Jun 16
ISP
Islip
DEN
Denver
$300 Roundtrip, found 5 days ago
$300
Roundtrip
found 5 days ago
Select Frontier Airlines flight, departing Wed, Jun 10 from Islip to Denver, returning Tue, Jun 16, priced at $300 found 5 days ago
Frontier Airlines
Fri, Jul 3 - Sat, Jul 11
ISP
Islip
DEN
Denver
$304 Roundtrip, found 20 hours ago
$304
Roundtrip
found 20 hours ago
Select Frontier Airlines flight, departing Fri, Jul 3 from Islip to Denver, returning Sat, Jul 11, priced at $304 found 20 hours ago
Frontier Airlines
Fri, Jul 3 - Fri, Jul 10
ISP
Islip
DEN
Denver
$310 Roundtrip, found 20 hours ago
$310
Roundtrip
found 20 hours ago
Select Frontier Airlines flight, departing Fri, Jul 3 from Islip to Denver, returning Fri, Jul 10, priced at $310 found 20 hours ago
Frontier Airlines
Wed, May 27 - Thu, May 28
ISP
Islip
DEN
Denver
$315 Roundtrip, found 5 days ago
$315
Roundtrip
found 5 days ago
Select Frontier Airlines flight, departing Wed, May 27 from Islip to Denver, returning Thu, May 28, priced at $315 found 5 days ago
Southwest Airlines
Tue, Aug 11 - Mon, Aug 17
ISP
Islip
DEN
Denver
$322 Roundtrip, found 6 days ago
$322
Roundtrip
found 6 days ago
Select Southwest Airlines flight, departing Tue, Aug 11 from Islip to Denver, returning Mon, Aug 17, priced at $322 found 6 days ago
JetBlue Airways
Tue, Jun 16 - Fri, Jun 19
ISP
Islip
DEN
Denver
$744 Roundtrip, found 1 day ago
$744
Roundtrip
found 1 day ago
Select JetBlue Airways flight, departing Tue, Jun 16 from Islip to Denver, returning Fri, Jun 19, priced at $744 found 1 day ago

Frequently asked questions

How much does a flight from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) cost?
You can find cheap one-way flights from $146 and cheap return flights from $280 Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) with Expedia. One-way flights typically cost between $182 and $1240, and return flights often range between $412 and $1565. Flight prices vary based on the month and day of the week you want to travel, as well as the airline and how far in advance you book your ticket. Filter your search on Expedia by "Price (lowest to highest)" to see the cheapest fares first, and use the Price Tracking tool to receive alerts when Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) ticket fares go up or down.*Typical price ranges based on flights available on Expedia in the last year. Prices include multi-airline options.
What is the cheapest month to fly from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.)?
The cheapest month to fly from ISP to DEN is June when demand is low. Traveling in off-peak or shoulder months is usually a good way to secure cheap tickets, just remember to avoid flying during holidays if you're able to. Use the calendar view in your search to see which months have low fares on this route.
Which airlines fly direct from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.)?
Enter ISP to DEN and your travel dates, then apply the 'Nonstop' filter to see only direct flights.
What is the cheapest airline that flies from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.)?
Frontier Airlines is one of the cheapest airlines offering nonstop flights from MacArthur (ISP) to Denver Intl. (DEN), with round-trip tickets starting from around $258. Use Expedia's search tool to compare the prices and schedules of airlines that fly this route to find the best option for your plans and budget.*Prices based on flights available on Expedia in the last year.
How do I find cheap flights from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.)?
To find a cheap flight from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.
What is the best time to fly from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.)?
The best time to fly is usually mid-week (Tuesday or Wednesday) and during early morning hours as flights tend to be cheaper, less crowded, and generally more on-time. Avoid major holidays and peak vacation seasons for smoother travel. Combining off-peak days and hours often gives the best combination of cost, comfort, and convenience.
What is the earliest flight from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.)?
The earliest flight from Islip, NY (MacArthur) to Denver, CO (Denver Intl.) typically departs at around 5:00 AM, operated by Southwest Airlines. This is a seasonal service active in May, allowing you to start your day early and maximize your time in Denver. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.
What are the most popular departure times for flights from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.)?
The most popular departure times for flights from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) are in the early afternoon, from 12pm to 3pm. About 30% of passengers prefer this time window. Many major carriers, including Southwest Airlines, 9K, and Southwest Airlines again, offer flights during this window. This timing is popular because it allows you to travel after the morning rush, making for a smoother airport experience.
How long does it take to fly from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.)?
Flights from ISP to DEN with one stop typically take around 7 hours 30 minutes, covering approximately 1,656 miles. Keep in mind that actual flight times can vary due to wind patterns, weather, and air traffic.
Can you fly business or first class from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.)?
Select the "Business class" and "First class" filters when looking for ISP to DEN flights on Expedia. This is the easiest way to compare prices, routes and flight times for your trip.
How do I earn miles on a Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) flight with Expedia?
It's easy to earn miles on a Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia.*Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.
What airports do you fly into for Denver from MacArthur (ISP)?
If you're planning to travel to Denver from MacArthur (ISP), you can fly into Denver Intl. (DEN) Some flights may connect through major hubs like Logan Intl. (BOS), Baltimore Washington Intl. Thurgood Marshall (BWI), Orlando Intl. (MCO) before reaching Denver. Compare routes and airports on Expedia to find the best flight options for your travel plans.
Is it cheaper to buy a plane ticket from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) at the last minute?
Typically, booking a last minute flight from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) flight and hotel package?
Securing a Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) Denver Vacation Packages is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.)?
If you booked your Islip, NY (ISP-MacArthur) to Denver, CO (DEN-Denver Intl.) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.

Travel information

Origin airport
MacArthur
Destination airport
Denver Intl.
Airlines serving
Frontier Airlines, JetBlue Airways, Southwest Airlines
Roundtrip price
$280
Distance
1655 mi

Book with confidence

Islip to Denver Flights

The cheapest times to fly from Islip to Denver

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Islip to Denver are during the month of June. You can find some of the cheapest flights from Islip to Denver with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Islip to Denver

Sunday is one of the best days to book for cheap flights from Islip to Denver: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Islip to Denver

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Islip to Denver in 2026. You can also book with separate airlines for your outbound and return journeys, from $146 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Islip to Denver flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Islip to Denver airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Islip to Denver Flights

*Flight schedules are subject to change.

*Available to One Key members.

 

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