DEN - ISP

$125 Find Cheap Flights from Denver to Islip

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Denver to Islip departing on 9/6. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy

KAYAK searches hundreds of travel sites at once for deals on flights to Islip

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Denver to Islip, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Denver to Islip, as well as popular online travel agencies
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Flights Deals

Cheap Flights from Denver to Islip (DEN-ISP)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Denver to Islip that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Denver to Islip

Thu, Sep 18 - Mon, Sep 22
Frontier Logo
8:32 am - 10:37 amDEN-ISP
24h 05m1 stop
Frontier Logo
5:07 pm - 9:08 amISP-DEN
18h 01m1 stop
$249Frontier
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Thu, Sep 25 - Sat, Sep 27
Southwest Logo
12:20 pm - 10:45 pmDEN-ISP
8h 25m1 stop
Southwest Logo
3:40 pm - 9:10 pmISP-DEN
7h 30m1 stop
$343Southwest
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Thu, Sep 25 - Sat, Sep 27
Southwest Logo
10:15 am - 10:45 pmDEN-ISP
10h 30m2 stops
Southwest Logo
3:40 pm - 9:10 pmISP-DEN
7h 30m1 stop
$348Southwest
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Fri, Aug 22 - Sun, Aug 24
Frontier Logo
11:59 pm - 4:11 pmDEN-ISP
14h 12m1 stop
Frontier Logo
9:01 pm - 8:35 amISP-DEN
13h 34m1 stop
$350Frontier
Find Deal
Thu, Sep 25 - Sat, Sep 27
Southwest Logo
11:15 am - 10:45 pmDEN-ISP
9h 30m2 stops
Southwest Logo
5:40 am - 2:00 pmISP-DEN
10h 20m2 stops
$353Southwest
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Sat, Jun 28 - Wed, Jul 9
Frontier Logo
6:00 am - 7:36 pmDEN-ISP
11h 36m1 stop
Frontier Logo
8:37 pm - 8:02 amISP-DEN
13h 25m1 stop
$361Frontier
Find Deal
Thu, Sep 18 - Tue, Sep 23
Frontier Logo
12:04 am - 10:37 amDEN-ISP
8h 33m1 stop
Frontier Logo
11:27 am - 9:00 amISP-DEN
23h 33m1 stop
$366Frontier
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Fri, Jul 11 - Sat, Jul 12
Frontier Logo
11:58 pm - 1:04 pmDEN-ISP
11h 06m1 stop
Frontier Logo
8:37 pm - 8:02 amISP-DEN
13h 25m1 stop
$368Frontier
Find Deal
Fri, Sep 5 - Sat, Sep 13
Frontier Logo
12:04 am - 10:37 amDEN-ISP
8h 33m1 stop
Frontier Logo
5:05 pm - 11:16 pmISP-DEN
8h 11m1 stop
$370Frontier
Find Deal
Fri, Aug 22 - Mon, Aug 25
Frontier Logo
11:59 pm - 4:11 pmDEN-ISP
14h 12m1 stop
Frontier Logo
8:59 am - 4:41 pmISP-DEN
9h 42m1 stop
$371Frontier
Find Deal
Useful Info

KAYAK's insights & trends for Denver to Islip flights

Get data-powered insights and trends into flights from Denver to Islip to help you find the cheapest flights, the best time to fly and much more.

What’s the cheapest day of the week to fly from Denver to Islip?

The average price of all round-trip flights from Denver to Islip clicked on KAYAK for each day over the last 12 months.

If you are looking for a flight deal from Denver to Islip, look for departures on Thursdays and avoid leaving on a Wednesday, as it's usually the priciest day. When flying back from Islip, Wednesday is the cheapest day to fly and Friday is the most expensive.

Good to know

Low seasonAugust
High seasonJune
Cheapest flight$125
Best time to beat the crowds with an average 42% drop in price.
Most popular time to fly and prices are also 0% lower on average.
Flight from Denver to Islip

When to book flights from Denver to Islip

Are your dates flexible? Find out the best times to travel from Denver to Islip based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from Denver to Islip

  • What is the cheapest flight from Denver to Islip?

    In the last 3 days, the lowest price for a flight from Denver to Islip was $125 for a one-way ticket and $249 for a round-trip.

  • Do I need a passport to fly between Denver and Islip?

    Even though you are not required to have a passport, keep in mind that an official ID is needed to board the airplane.

  • Which airports will I be using when flying from Denver to Islip?

    When flying out of Denver you will be using Denver Intl. You will be landing at Islip, also known as Islip Long Island.

  • Which aircraft models fly most regularly from Denver to Islip?

    We unfortunately don’t have that data for this specific route.

  • Which is the best airline for flights from Denver to Islip, Southwest or Frontier?

    The two airlines most popular with KAYAK users for flights from Denver to Islip are Southwest and Frontier. With an average price for the route of $456 and an overall rating of 8.0, Southwest is the most popular choice. Frontier is also a great choice for the route, with an average price of $264 and an overall rating of 5.9.

  • How does KAYAK find such low prices on flights from Denver to Islip?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Denver to Islip.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Denver to Islip?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Islip from Denver is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Denver to Islip?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Islip with an airline and back to Denver with another airline. Booking your flights between Denver and ISP can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Denver to Islip?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Islip from Denver up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Top airlines flying from Denver to Islip

 
See real verified KAYAK customer reviews for airlines flying from Denver to Islip. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Denver to Islip? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4287 reviews
7.1Food
8.2Boarding
7.6Entertainment
8.0Comfort
8.6Crew
Airline reviews

Southwest is typically delayed, and it gets wearisome. It is no longer a discount airline and you get way less than you pay for when it comes to comfort and Ce.

6.0 GoodDavid, Jun 2025BWI - COS
Read more Southwest reviews

Southwest is typically delayed, and it gets wearisome. It is no longer a discount airline and you get way less than you pay for when it comes to comfort and Ce.

We sat on the plane on the tarmac for 4 hours.

I'm not a fan of Southwest's model. I don't like the herding style of boarding.

Flight crew and cabin crew were great. I had to rearrange flights because my original flight was 3hrs delayed for weather, the rub is the flight I moved to boarded on time then we sat at the gate for 2 hours because scheduling stole our first officer for another flight, TWICE. Then our actual FO was an hour delayed. To make it worse my original flight went from a 3 hour delay to departing 15min EARLY. Just poor scheduling operations all around.

Bring back peanuts Take our drink orders when were all seated, especially after you switch to assigned seating.

Staff was far less than helpful at all times. Departure and arrival times mean nothing to Southwest. Extremely disappointed, will never fly with them again, and I’ll be sure to share my experience with all.

It is southwest seat was ok. Not the most comfortable seat

I’ve always loved Southwest. No issues at all. I was flying standby and the gate agent was extremely friendly and helpful. Boarding was smooth and I was able to get a window seat in the emergency exit row. Crew was fantastic! They were very professional and accommodating. We had to divert from our destination due to weather but the flight crew kept everyone at ease and informed us of all pertinent information. Excellent flight

The price of the tickets isn't matching the flight experience. No matter how long the flight is, you're only getting pretzels. The flight attendants looked unkept and over it.

Plz don't take away free bags and free seating

I never got to experience the flight because they delayed my first flight and I missed this one. Then Frontier didn't want to help me rebook a flight to get me to my final destination.

The Boarding process in Denver was chaotic, and since the line was so long, we were lined up very far from the gate. If there were any announcements from the gate staff, we didn't hear them. The flight attendants were spectacular. The only negative part of the flight was sitting by a 2 1/2 year old who was unruly and unfortunately had parents that matched his behaviors. Also, the restaurants in Denver on the E concourse, they didn't have food (passengers could only order 1 item on the entire menu) or the restaurants had 12-14 people waiting for orders to be prepared and another 6 people waiting to order. If you have a layover in Denver and need to grab food, be prepared to visit the shops with pre-packaged sandwiches, or you can visit another concourse but it may take a while to transit throughout the airport.

Everything went as planned. Crew was great. Seats were still not that comfortable.

they delayed my flight which ended up, causing my layover flight to leave without me, resulting in me missing a flight and having to stay overnight in Houston international. I got no compensation other than a flight to my original location only a day later. i’ve never experienced such a unprofessional situation

The seats were extremely hard and uncomfortable, even for a budget airline.

Boarding was very well executed. Got my bag right away.

Overall experience good. There was no food and seats were not terribly comfortable.

There was nothing to like, flight delayed had to move to different departure areas, disorganized to say the leasr

There were a lot of issues every step of the process. Check in, security, boarding, and dealing with luggage. Plus the money you think you are saving you end up using in hidden fees.

The flight attendant was arguing with a passenger before takeoff. The passenger was frustrated but the flight attendant should have handled it with grace, but instead she was nasty and rude. The seats were comfortable and the flight was uneventful. I wish we didn’t have to pay for drinks or snacks but that’s what you get with a budget airline.

Everything you need to know for your flight from Denver to Islip

Information on your arrival and departure airports

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