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Cheap flights from Islip to London from £699

This is the cheapest return flight price found by a momondo user in the last 72 hours by searching for a flight from Islip to London departing on 22/10. 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 to London

Cheap return flights

JetBlue Logo
11:35 - 20:45ISP-LHR
28h 10m2 stops
JetBlue Logo
07:25 - 13:02LHR-ISP
33h 37m2 stops
£699JetBlue
Find Deal
Wed, 22 Oct - Wed, 29 Oct
Logo
07:30 - 09:05ISP-LHR
20h 35m2 stops
Logo
09:50 - 19:45LHR-ISP
14h 55m2 stops
£784
Find Deal
Thu, 16 Oct - Wed, 22 Oct
Logo
09:59 - 06:30ISP-LHR
15h 31m1 stop
Logo
06:00 - 19:45LHR-ISP
18h 45m2 stops
£1,264
Find Deal
Thu, 16 Oct - Wed, 22 Oct
Logo
09:59 - 06:30ISP-LHR
15h 31m1 stop
Logo
08:25 - 16:15LHR-ISP
12h 50m1 stop
£1,456
Find Deal
Thu, 16 Oct - Wed, 22 Oct
Logo
12:40 - 11:25ISP-LHR
17h 45m2 stops
Logo
09:20 - 16:15LHR-ISP
11h 55m1 stop
£1,881
Find Deal
Thu, 13 Nov - Sun, 23 Nov

momondo Fare Finder

 
Customise your flight search to find flights from Islip 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 279,928 searches. Data last updated 16 September 2025.
Use the filters below to find and compare flights from Islip 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 22/10

11:35-20:45

2 stops28h 10m

London Heathrow

Wed 29/10

07:25-13:02

2 stops33h 37m

£699

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Thu 16/10

07:30-09:05

2 stops20h 35m

London Heathrow

Wed 22/10

09:50-19:45

2 stops14h 55m

£784

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Thu 16/10

09:59-06:30

1 stop15h 31m

London Heathrow

Wed 22/10

06:00-19:45

2 stops18h 45m

£1,264

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Thu 16/10

09:59-06:30

1 stop15h 31m

London Heathrow

Wed 22/10

08:25-16:15

1 stop12h 50m

£1,456

IslipLondon

ISP - LHR

ISPLHR

Islip Long Island

Thu 13/11

12:40-11:25

2 stops17h 45m

London Heathrow

Sun 23/11

09:20-16:15

1 stop11h 55m

£1,881

Flights are sorted by cheapest return flights first.

Sorted by cheapest first

See travel insights to London from

How to get the cheapest flight ticket from Islip 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?

On average, the least expensive day to fly to London Heathrow Airport from Islip is on a Wednesday. momondo users have found tickets for Wednesday departures for as low as £423. However, this price may fluctuate depending on the airline, the season, and holidays. Be sure to avoid booking your departure on a Saturday as prices are generally higher than usual. According to our data, the average ticket price to London Heathrow Airport on Saturday is £484.

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 midday. momondo users have found flights departing from Islip to London Heathrow Airport at midday for as low as £410. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. If you have a flexible travel schedule, then try to avoid flying in the afternoon when prices are £468 on average. Flights to London Heathrow Airport from Islip in the afternoon are generally more expensive because this time of day is more convenient for travellers’ schedules.

When to book flights from Islip to London Heathrow Airport

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

Cheap Islip 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 to London Heathrow Airport

Direct flights

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

    London Heathrow is 3412.8 mi away from Islip Long Island. 15h 31m is a normal flight duration for this route.

  • 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?

    Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for 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.

Travelling to a place near London?

Book flights to London if you plan to visit one of these locations
Eastbourne
Luton
Milton Keynes
Maidstone
Gatwick
Slough
Northampton
Swindon
Canterbury
Stratford-upon-Avon
Southend-on-Sea
Ipswich
Ilford
Guildford
Swanage
Poole
Colchester
Worthing
Salisbury
Chelmsford

Why use momondo?

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

It is quick and easy to find Islip to London flights on momondo. We search and return numerous flight options from various airlines and agents. You can then use our filters to narrow your search until you have found the most convenient flight to London that suits you.

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

Yes. momondo allows you to filter the results for Islip to London flights to just show those with flexible booking policies.

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

momondo helps you find the best flight between Islip and London by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.

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

If you are simply researching potential flights to London, momondo offers a useful price alert feature which will track prices for flights to London from Islip and alert you when they change.

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