How does KAYAK find such low prices on flights from Illinois to London?

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 Illinois to London.

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

KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London from Illinois 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 Illinois to London?

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 London with an airline and back to Illinois with another airline.

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

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 London from Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

$301 CHEAP FLIGHTS from Illinois to London

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Cheap Flights from Illinois to London

Discover the best prices for you by selecting your travel dates on KAYAK.

Round-trip

One-way

Last minute

Direct

Recent round-trip flight deals from Illinois to London

Wed, Dec 2 - Wed, Dec 9

6:05 pm - 6:50 amSTL Lambert-St Louis-LGW London Gatwick

30h 45m1 stop Orlando

9:45 am - 12:41 amLGW London Gatwick-STL Lambert-St Louis

20h 56m1 stop Orlando

$644Multiple Airlines

Sat, Nov 7 - Tue, Nov 17

4:26 pm - 8:15 amSTL Lambert-St Louis-LGW London Gatwick

33h 49m1 stop Orlando

9:35 am - 5:40 pmLGW London Gatwick-STL Lambert-St Louis

38h 05m2 stops Orlando Atlanta Hartsfield-Jackson

$647Multiple Airlines

Mon, Oct 19 - Wed, Oct 28

7:15 pm - 4:00 pmORD Chicago O'Hare Intl-LHR London Heathrow

14h 45m1 stop Kastrup Copenhagen

10:20 am - 5:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

12h 25m1 stop Kastrup Copenhagen

$705Scandinavian Airlines

Tue, Oct 20 - Thu, Oct 29

7:15 pm - 4:00 pmORD Chicago O'Hare Intl-LHR London Heathrow

14h 45m1 stop Kastrup Copenhagen

6:40 am - 5:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

16h 05m1 stop Kastrup Copenhagen

$705Scandinavian Airlines

Thu, Dec 10 - Sun, Dec 20

6:30 pm - 10:50 amORD Chicago O'Hare Intl-LHR London Heathrow

10h 20m1 stop Reykjavik Keflavik Intl

8:35 pm - 5:20 pmLHR London Heathrow-ORD Chicago O'Hare Intl

26h 45m1 stop Reykjavik Keflavik Intl

$706Icelandair

Fri, Dec 11 - Sun, Dec 20

6:30 pm - 10:50 amORD Chicago O'Hare Intl-LHR London Heathrow

10h 20m1 stop Reykjavik Keflavik Intl

8:35 pm - 5:20 pmLHR London Heathrow-ORD Chicago O'Hare Intl

26h 45m1 stop Reykjavik Keflavik Intl

$706Icelandair

Wed, Oct 21 - Wed, Nov 4

6:00 pm - 12:45 pmORD Chicago O'Hare Intl-LHR London Heathrow

12h 45m1 stop Lisbon Humberto Delgado

6:00 am - 3:30 pmLHR London Heathrow-ORD Chicago O'Hare Intl

15h 30m1 stop Lisbon Humberto Delgado

$709TAP AIR PORTUGAL

Sun, Nov 1 - Sat, Nov 7

8:10 pm - 9:35 pmORD Chicago O'Hare Intl-LHR London Heathrow

19h 25m1 stop Lisbon Humberto Delgado

6:30 pm - 3:30 pmLHR London Heathrow-ORD Chicago O'Hare Intl

27h 00m1 stop Lisbon Humberto Delgado

$709TAP AIR PORTUGAL

Thu, Oct 8 - Thu, Dec 3

7:05 pm - 9:05 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mnonstop

11:00 am - 1:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$715British Airways

Fri, Nov 6 - Sat, Nov 14

5:10 pm - 6:55 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

11:00 am - 1:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$811British Airways

Recent last minute flight deals from Illinois to London

Sat, Sep 5 - Thu, Sep 17

6:05 pm - 6:50 pmORD Chicago O'Hare Intl-LHR London Heathrow

18h 45m1 stop Lisbon Humberto Delgado

6:45 pm - 4:00 pmLHR London Heathrow-ORD Chicago O'Hare Intl

27h 15m1 stop Lisbon Humberto Delgado

$837TAP AIR PORTUGAL

Wed, Sep 2 - Fri, Sep 11

11:13 am - 7:40 amSTL Lambert-St Louis-LHR London Heathrow

14h 27m2 stops Minneapolis St Paul Amsterdam Schiphol

8:40 am - 8:35 pmLHR London Heathrow-STL Lambert-St Louis

17h 55m2 stops Amsterdam Schiphol Detroit Metropolitan Wayne County

$877Delta

Wed, Sep 2 - Fri, Sep 11

11:13 am - 7:55 amSTL Lambert-St Louis-LCY London City

14h 42m2 stops Minneapolis St Paul Amsterdam Schiphol

9:20 am - 7:58 pmLCY London City-STL Lambert-St Louis

16h 38m2 stops Amsterdam Schiphol Atlanta Hartsfield-Jackson

$898Delta

Sat, Sep 5 - Sat, Sep 19

5:27 pm - 9:30 amORD Chicago O'Hare Intl-LHR London Heathrow

34h 03m1 stop New York John F Kennedy Intl

8:15 am - 9:58 amLHR London Heathrow-ORD Chicago O'Hare Intl

31h 43m1 stop New York John F Kennedy Intl

$940JetBlue

Tue, Sep 1 - Sat, Oct 31

7:15 pm - 5:40 pmORD Chicago O'Hare Intl-LHR London Heathrow

16h 25m1 stop Kastrup Copenhagen

6:40 am - 5:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

16h 05m1 stop Kastrup Copenhagen

$946Scandinavian Airlines

Sun, Sep 6 - Sat, Sep 19

5:23 pm - 11:20 amSTL Lambert-St Louis-LHR London Heathrow

11h 57m1 stop Atlanta Hartsfield-Jackson

9:20 am - 4:32 pmLHR London Heathrow-STL Lambert-St Louis

13h 12m1 stop Atlanta Hartsfield-Jackson

$947Multiple Airlines

Sat, Sep 5 - Thu, Sep 17

6:05 pm - 10:55 pmORD Chicago O'Hare Intl-LHR London Heathrow

22h 50m1 stop Lisbon Humberto Delgado

6:45 pm - 4:00 pmLHR London Heathrow-ORD Chicago O'Hare Intl

27h 15m1 stop Lisbon Humberto Delgado

$950TAP AIR PORTUGAL

Sat, Sep 5 - Fri, Oct 2

7:25 pm - 11:55 amORD Chicago O'Hare Intl-LHR London Heathrow

10h 30m1 stop Reykjavik Keflavik Intl

1:05 pm - 9:25 pmLHR London Heathrow-ORD Chicago O'Hare Intl

14h 20m1 stop Reykjavik Keflavik Intl

$958Icelandair

Sat, Sep 5 - Fri, Oct 2

7:25 pm - 11:55 amORD Chicago O'Hare Intl-LHR London Heathrow

10h 30m1 stop Reykjavik Keflavik Intl

1:05 pm - 9:25 pmLHR London Heathrow-ORD Chicago O'Hare Intl

14h 20m1 stop Reykjavik Keflavik Intl

$959Icelandair

Sat, Sep 5 - Thu, Sep 17

7:15 pm - 4:25 pmORD Chicago O'Hare Intl-LHR London Heathrow

15h 10m2 stops Kastrup Copenhagen Oslo Gardermoen

7:30 pm - 4:10 pmLHR London Heathrow-ORD Chicago O'Hare Intl

26h 40m1 stop Kastrup Copenhagen

$973Scandinavian Airlines

Recent direct flight deals from Illinois to London

Thu, Oct 8 - Thu, Dec 3

7:05 pm - 9:05 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mnonstop

11:00 am - 1:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$715British Airways

Mon, Dec 7 - Tue, Dec 15

6:50 pm - 8:35 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

11:00 am - 1:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$787Iberia

Fri, Nov 6 - Sat, Nov 14

5:10 pm - 6:55 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

11:00 am - 1:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$811British Airways

Mon, Sep 28 - Tue, Oct 6

5:55 pm - 7:40 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

2:45 pm - 5:35 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 50mnonstop

$835Finnair

Mon, Sep 28 - Tue, Oct 6

5:55 pm - 7:40 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

2:45 pm - 5:35 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 50mnonstop

$837Finnair

Tue, Oct 13 - Tue, Oct 20

10:30 pm - 12:15 pmORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

12:15 pm - 3:00 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$856Iberia

Tue, Dec 1 - Wed, Dec 9

5:45 pm - 7:55 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 10mnonstop

7:40 am - 10:45 amLHR London Heathrow-ORD Chicago O'Hare Intl

9h 05mnonstop

$866Lufthansa

Mon, Nov 30 - Wed, Dec 9

9:50 pm - 12:00 pmORD Chicago O'Hare Intl-LHR London Heathrow

8h 10mnonstop

1:35 pm - 4:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 20mnonstop

$883United Airlines

Tue, Dec 1 - Wed, Dec 9

3:45 pm - 5:55 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 10mnonstop

1:35 pm - 4:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 20mnonstop

$883United Airlines

Wed, Oct 14 - Thu, Oct 29

4:25 pm - 6:45 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 20mnonstop

1:35 pm - 5:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 20mnonstop

$884Lufthansa

Useful Info

Low season	February
High season	March
Cheapest flight	$301

Best time to beat the crowds with an average 19% drop in price.

Most popular time to fly and prices are also 16% lower on average.

Flight from Chicago O'Hare Airport to London Heathrow Airport

Verified travelerFlew with British Airways-Mar 2026

Take early morning flights to adjust to weather-related delays.

Verified travelerFlew with British Airways-Jun 2025

Get a wheel chair if you have difficulty walking

JoeFlew with Iberia-Apr 2025

Get there early. Nice airport options while you wait.

Verified travelerFlew with Iberia-May 2025

Get to the airport early so you’re relaxed. Con yourself into believing it’s bedtime and try to sleep so that you can keep going all day when you get there. If you can afford more comfy seats it might be worth it - though I always have the cheap ones so I can’t say for sure. Try very hard not to. sit in the middle. I’m small and the guy next to me played games all night and didn’t care that he continually ( with every move) jabbed me with his arm. This was my first flight with Cheap Flights and it was far less convenient than other times I’ve flown overseas.

DinaFlew with United Airlines-Jan 2025

Anticipate delays, prepare for long walks through Heathrow to baggage claim or for connections.

KariFlew with British Airways-May 2024

Always check to confirm your assistance is in system. No wheelchair waiting for me in London. Had no clue about airport or how to get around. Got lost easy

AaronFlew with American Airlines-Dec 2023

Find a flight where you are allowed to choose your seats before the day of boarding for anything international.

How does KAYAK find such low prices on flights from Illinois to London?
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 Illinois to London.
How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Illinois to London?
KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London from Illinois 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 Illinois to London?
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 London with an airline and back to Illinois with another airline.
What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Illinois to London?
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 London from Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Hounslow

Hayes

Slough

Richmond

Wembley

Luton

Ilford

Eastbourne

Crawley

Bedford

Guildford

Watford

Colchester

Ipswich

Kingston upon Thames

Twickenham

St. Albans

Harrow

Newbury

Chelmsford

Everything you need to know for your flight to London

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Cabin class types available on flights to Illinois

First Class flights to Londonfrom $4,521

Business Class flights to Londonfrom $3,740

Premium Economy Class flights to Londonfrom $1,711

Economy Class flights to Londonfrom $835

$301 Find Cheap Flights from Illinois to London - Compare and Save

Cheap Flights from Illinois to London

Recent round-trip flight deals from Illinois to London

Recent one-way flight deals from Illinois to London

Recent last minute flight deals from Illinois to London

Recent direct flight deals from Illinois to London

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Flights from Illinois to London: the best tips from KAYAK users

FAQs for booking flights from Illinois to London

Traveling to a place near London?

Everything you need to know for your flight to London

Cabin class types available on flights to Illinois

Complete your trip to London with a hotel stay or car rental

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Find deals for your return flight