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Cheap flights from Islip, New York to London from $1,621

This is the cheapest round-trip flight price found by a momondo user in the last 72 hours by searching for a flight from Islip, New York to London departing on 12/17. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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Find the cheapest flights from Islip, New York to London

Cheap round-trip flights

Enter your travel dates to find the best prices.
Multiple Airlines Logo
9:59 am - 11:20 amISP-LHR
20h 21m2 stops
Multiple Airlines Logo
6:30 am - 7:45 pmLHR-ISP
18h 15m2 stops
$1,621Multiple Airlines
Find Deal
Wed, Dec 17 - Wed, Dec 24
Multiple Airlines Logo
9:59 am - 11:20 amISP-LHR
20h 21m2 stops
Multiple Airlines Logo
1:30 pm - 7:45 pmLHR-ISP
11h 15m1 stop
$1,653Multiple Airlines
Find Deal
Wed, Dec 17 - Wed, Dec 24
Multiple Airlines Logo
1:27 pm - 12:05 pmISP-LHR
17h 38m2 stops
Multiple Airlines Logo
12:35 pm - 5:55 pmLHR-ISP
34h 20m2 stops
$1,732Multiple Airlines
Find Deal
Fri, Dec 19 - Fri, Dec 26
Multiple Airlines Logo
7:30 am - 7:30 pmISP-LHR
31h 00m2 stops
Multiple Airlines Logo
1:25 pm - 11:04 amLHR-ISP
26h 39m3 stops
$1,764Multiple Airlines
Find Deal
Fri, Dec 19 - Fri, Dec 26
Multiple Airlines Logo
9:59 am - 7:10 amISP-LHR
16h 11m3 stops
Multiple Airlines Logo
6:30 am - 7:45 pmLHR-ISP
18h 15m2 stops
$1,807Multiple Airlines
Find Deal
Wed, Dec 17 - Wed, Dec 24
Multiple Airlines Logo
7:30 am - 7:30 pmISP-LHR
31h 00m2 stops
Multiple Airlines Logo
7:10 pm - 11:04 amLHR-ISP
20h 54m1 stop
$2,078Multiple Airlines
Find Deal
Fri, Dec 19 - Fri, Dec 26
Multiple Airlines Logo
12:40 pm - 11:25 amISP-LHR
17h 45m2 stops
Multiple Airlines Logo
9:20 am - 4:15 pmLHR-ISP
11h 55m1 stop
$2,385Multiple Airlines
Find Deal
Thu, Dec 18 - Thu, Dec 25
Multiple Airlines Logo
12:40 pm - 6:55 amISP-LHR
13h 15m1 stop
Multiple Airlines Logo
9:20 am - 4:15 pmLHR-ISP
11h 55m1 stop
$2,519Multiple Airlines
Find Deal
Wed, Dec 17 - Wed, Dec 24
Multiple Airlines Logo
12:40 pm - 9:15 amISP-LHR
15h 35m2 stops
Multiple Airlines Logo
9:20 am - 4:15 pmLHR-ISP
11h 55m1 stop
$2,607Multiple Airlines
Find Deal
Mon, Dec 15 - Mon, Dec 22
Multiple Airlines Logo
12:40 pm - 6:55 amISP-LHR
13h 15m1 stop
Multiple Airlines Logo
9:20 am - 4:15 pmLHR-ISP
11h 55m1 stop
$3,333Multiple Airlines
Find Deal
Fri, Dec 19 - Fri, Dec 26

momondo Fare Finder

 
Customize your flight search to find flights from Islip, New York to London Heathrow Airport 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, momondo users made 832,500 searches. Data last updated November 4, 2025.
Use the filters below to find and compare flights from Islip, New York to London Heathrow Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Wed 12/17

9:59 am-11:20 am

2 stops20h 21m

London Heathrow

Wed 12/24

6:30 am-7:45 pm

2 stops18h 15m

$1,621

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Wed 12/17

9:59 am-11:20 am

2 stops20h 21m

London Heathrow

Wed 12/24

1:30 pm-7:45 pm

1 stop11h 15m

$1,653

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Fri 12/19

1:27 pm-12:05 pm

2 stops17h 38m

London Heathrow

Fri 12/26

12:35 pm-5:55 pm

2 stops34h 20m

$1,732

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Fri 12/19

7:30 am-7:30 pm

2 stops31h 00m

London Heathrow

Fri 12/26

1:25 pm-11:04 am

3 stops26h 39m

$1,764

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Wed 12/17

9:59 am-7:10 am

3 stops16h 11m

London Heathrow

Wed 12/24

6:30 am-7:45 pm

2 stops18h 15m

$1,807

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Fri 12/19

7:30 am-7:30 pm

2 stops31h 00m

London Heathrow

Fri 12/26

7:10 pm-11:04 am

1 stop20h 54m

$2,078

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Thu 12/18

12:40 pm-11:25 am

2 stops17h 45m

London Heathrow

Thu 12/25

9:20 am-4:15 pm

1 stop11h 55m

$2,385

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Wed 12/17

12:40 pm-6:55 am

1 stop13h 15m

London Heathrow

Wed 12/24

9:20 am-4:15 pm

1 stop11h 55m

$2,519

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Mon 12/15

12:40 pm-9:15 am

2 stops15h 35m

London Heathrow

Mon 12/22

9:20 am-4:15 pm

1 stop11h 55m

$2,607

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Fri 12/19

12:40 pm-6:55 am

1 stop13h 15m

London Heathrow

Fri 12/26

9:20 am-4:15 pm

1 stop11h 55m

$3,333

Flights are sorted by cheapest round-trip flights first.

Sorted by cheapest first

See travel insights to London from

How to get the cheapest flight ticket from Islip, New York to London Heathrow Airport

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest day to depart on your flight to London Heathrow Airport?

Our data shows that Wednesday is the least expensive day to fly to London Heathrow Airport. Tickets to fly out on this day can be as low as $643. The most expensive day to fly to London Heathrow Airport is Sunday, with ticket prices averaging around $683.

What is the cheapest time of day to depart on your flight to London Heathrow Airport?

According to our data, the cheapest time of day to fly to London Heathrow Airport is at noon. momondo users have found flights departing from Islip, New York to London Heathrow Airport at noon for as low as $586. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. Flights in the afternoon are often more expensive with an average ticket price of $693.

When to book flights from Islip, New York to London Heathrow Airport

Are you open to changing your travel dates? Check out the ideal times to fly from Islip, New York to London Heathrow Airport according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Islip, New York to London Heathrow Airport (ISP to LHR) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Islip, New York to London Heathrow Airport

Direct flights

None
There are no direct flights from Islip, New York to London Heathrow Airport. There are no popular flight routes from Islip, New York to London Heathrow Airport.
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  • How far is Islip Long Island to London Heathrow by plane?

    A flight from Islip Long Island to London Heathrow will travel around 3412.8 mi. Typically, this will take 13h 15m by plane in normal conditions.

  • When did momondo last update prices for flights from Islip Long Island Airport to London Heathrow Airport?

    Prices for flights from Islip Long Island Airport to London Heathrow Airport are refreshed on a daily basis.

  • How old do you have to be to fly from Islip Long Island Airport to London Heathrow Airport?

    The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Islip Long Island Airport to London Heathrow Airport.

  • What documentation or ID do you need to fly to London Heathrow Airport?

    The necessary travel and health documents for your London Heathrow Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.

Traveling to a place near London?

Book flights to London if you plan to visit one of these locations
Gatwick
Hounslow
Milton Keynes
Dover
Luton
Slough
Guildford
Hayes
Dartford
Crawley
Stratford-upon-Avon
Brentwood
Salisbury
Chelmsford
Folkestone
Romford
Ilford
Swindon
Cobham
Wembley

Why use momondo?

Why should I use momondo to find a flight deal from Islip to London?

To find the flight that best suits your needs, momondo gathers a range of flights from a large pool of different airlines and agents; you can then use our insights and filters to find and book the right flight to London from Islip.

Can I find flights from Islip to London with flexible booking policies on momondo?

Yes. momondo enables you to select and highlight flights to London from Islip with this policy.

How can momondo help me find flights from Islip to London?

momondo provides multiple filters to help you find the best flight to London from Islip. Filter by price, airline, airports, cabin, aircraft, payment method, number of stops and more.

I’m not ready to book a flight from Islip to London right now. Can momondo alert me if prices change?

Yes. momondo can track prices for Islip to London flights and alert you when they change. Perform a search to set up the price alert. All that is required is a valid email address.

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