In terms of precipitation, rainfall in Islip ranges from 3.3 - 4.4 inches per month. March is typically the wettest month, when rainfall can reach 4.4 in. February is typically the driest time to visit Islip when rainfall is around 3.3 in.

If weather is an important factor for your trip to Islip, 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).

How far in advance should I book a flight from London to Islip?

Travelers have found it’s best to book a flight 38 days in advance to save up to 29% compared to booking the same week of travel. As your travel date approaches, the cost of this flight route may potentially increase. While opting to book 38 days out may not be an option for all, there are still additional ways to secure a deal in the near future. You might find a flight from London to Islip 1-2 weeks in advance for as low as $517, or $841 for flights within the next 24 hours.

What is the cheapest month to fly from London to Islip?

Due to multiple factors, expect to potentially pay more when booking in December. For low rates, September can be a great choice for travel to Islip. Flights to Islip from London in September are about $545 on average during September, but can be found for as low as $369.

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

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from London to Islip as you normally would.

What airport do you fly into for flights to Islip from London?

Located just 7.2 mi from the city center, Islip Long Island is the airport most travelers will use when flying to Islip from London. Booking flights from London to Long Island (ISP) should be relatively easy as there are 0 daily inbound flights from London from 0 different airlines.

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

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

How can I find direct flights from London to Islip?

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

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

Yes. Cheapflights offers flight deals from London to Islip by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$5,538+ Flights from London to Islip

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Cheap flight deals from London to Islip

Round-trip from	$5,538 (TravelUp)
Popular in	December
Cheapest in	September
Average price	$481

From London (LON) to Islip Long Island

Search Deals

Highest demand for flights based on searches. 3% potential increase in price ($18 potential increase over avg. RT price).

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Cheapest flight prices on average. 1% potential price decrease ($11 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 London to Islip

Cheapest flights from London to Islip
Explore the most affordable flight options available from London to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 14, 2025.

Fri 12/121:30 pmLHR - ISP

1 stop11h 31mMultiple Airlines

Sat 1/312:40 pmISP - LHR

1 stop12h 50mMultiple Airlines

Deal found 9/12

$5,538

Best flights from London to Islip
Discover carefully curated flight deals from London to Islip that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 14, 2025.

Fri 12/121:30 pmLHR - ISP

1 stop11h 31mMultiple Airlines

Sat 1/312:40 pmISP - LHR

1 stop12h 50mMultiple Airlines

Deal found 9/12

$5,538

Fly from

Fly to

Route

Depart

Return

Price

LondonIslip

LHR - ISP

LHRISP

London Heathrow

Fri 12/12

1:30 pm-8:01 pm

1 stop11h 31m

Islip Long Island

Sat 1/3

12:40 pm-6:30 am

1 stop12h 50m

$5,538

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/12

Best time to book a flight from London to Islip

Have a flexible travel schedule? Discover the best time to fly to Islip from London 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 London to Islip

What is the cheapest month to book a flight from London to Islip?

Currently, January is the cheapest month in which you can book a flight from London to Islip (average of $108). Flying from London to Islip in November is currently the most expensive (average of $213). 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.

Related info for your journey

What airport do you fly into for flights to Islip from London?
Located just 7.2 mi from the city center, Islip Long Island is the airport most travelers will use when flying to Islip from London. Booking flights from London to Long Island (ISP) should be relatively easy as there are 0 daily inbound flights from London from 0 different airlines.
Can I find deals for flights from London to Islip that include hotel bookings?
Yes. In addition to deals on London to Islip flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from London to Islip?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from London to Islip.
Can I find deals for business class flights from London to Islip?
Yes. Cheapflights offers flight deals from London to Islip 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 London to Islip?
Currently, January is the cheapest month in which you can book a flight from London to Islip (average of $108). Flying from London to Islip in November is currently the most expensive (average of $213). 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.

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$5,538+ Cheap flights from London (LON) to Islip (ISP)

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 12/12. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from London to Islip with Cheapflights

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2. Select your favorite providers

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Cheap flight deals from London to Islip

Round-trip from

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Find flight deals from London to Islip

Cheapest flights from London to IslipExplore the most affordable flight options available from London to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 14, 2025.

Explore the most affordable flight options available from London to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 14, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from London to Islip that are best for you.

Best time to book a flight from London to Islip

Have a flexible travel schedule? Discover the best time to fly to Islip from London with our price prediction graph.

Cheapflights Insights

Everything you need to know about your flight from London to Islip

What is the cheapest month to book a flight from London to Islip?

Related info for your journey

Find useful and relevant information for your journey from London to Islip. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

What airport do you fly into for flights to Islip from London?

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

How can I find direct flights from London to Islip?

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

What is the cheapest month to book a flight from London to Islip?

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Cheapest flights from London to Islip
Explore the most affordable flight options available from London to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 14, 2025.