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.

$320 CHEAP FLIGHTS from Illinois to London

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Cheap Flights from Illinois to London

Cheap flights from Illinois to London with top airlines, updated regularly. Compare round-trip, one-way, direct and last-minute deals.

Round-trip

One-way

Last minute

Direct

Tue, Nov 24 - Tue, Dec 1

6:30 pm - 9:40 pmORD Chicago O'Hare Intl-LHR London Heathrow

21h 10m3 stops Reykjavik Keflavik Intl Stockholm Arlanda Kastrup Copenhagen

6:40 am - 5:20 pmLHR London Heathrow-ORD Chicago O'Hare Intl

16h 40m2 stops Stockholm Arlanda Reykjavik Keflavik Intl

$721Multiple Airlines

Sun, Nov 8 - Tue, Nov 17

8:10 pm - 8:35 pmORD Chicago O'Hare Intl-LGW London Gatwick

18h 25m2 stops Lisbon Humberto Delgado Porto

7:00 am - 5:20 pmLGW London Gatwick-ORD Chicago O'Hare Intl

16h 20m2 stops Kastrup Copenhagen Reykjavik Keflavik Intl

$722Multiple Airlines

Sat, Mar 13 - Fri, Mar 19

7:10 pm - 6:30 pmORD Chicago O'Hare Intl-LHR London Heathrow

17h 20m1 stop Kastrup Copenhagen

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

16h 05m1 stop Kastrup Copenhagen

$722Scandinavian Airlines

Fri, Apr 2 - Fri, Apr 9

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

14h 45m1 stop Kastrup Copenhagen

5:00 pm - 4:10 pmLHR London Heathrow-ORD Chicago O'Hare Intl

29h 10m1 stop Kastrup Copenhagen

$722Scandinavian Airlines

Mon, Nov 9 - Mon, Nov 16

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

10h 20m1 stop Reykjavik Keflavik Intl

12:15 pm - 5:20 pmLHR London Heathrow-ORD Chicago O'Hare Intl

35h 05m1 stop Reykjavik Keflavik Intl

$723Icelandair

Fri, Jan 22 - Fri, Jan 29

8:10 pm - 5:30 pmORD Chicago O'Hare Intl-LHR London Heathrow

15h 20m1 stop Lisbon Humberto Delgado

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

15h 30m1 stop Lisbon Humberto Delgado

$724TAP AIR PORTUGAL

Fri, Jan 22 - Sun, Jan 31

8:10 pm - 5:30 pmORD Chicago O'Hare Intl-LHR London Heathrow

15h 20m1 stop Lisbon Humberto Delgado

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

15h 30m1 stop Lisbon Humberto Delgado

$724TAP AIR PORTUGAL

Mon, Nov 9 - Mon, Nov 16

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

10h 20m1 stop Reykjavik Keflavik Intl

12:15 pm - 5:20 pmLHR London Heathrow-ORD Chicago O'Hare Intl

35h 05m1 stop Reykjavik Keflavik Intl

$725Icelandair

Mon, Jan 25 - Wed, Jan 27

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

8h 10mnonstop

9:00 am - 4:15 pmLHR London Heathrow-ORD Chicago O'Hare Intl

13h 15m1 stop Zurich

$731United Airlines

Tue, Mar 30 - Thu, Apr 1

9:30 pm - 11:55 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 25mnonstop

8:45 am - 3:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

13h 10m1 stop Zurich

$731United Airlines

Wed, Oct 14 - Wed, Nov 4

6:00 pm - 10:00 pmORD Chicago O'Hare Intl-LHR London Heathrow

22h 00m1 stop Lisbon Humberto Delgado

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

15h 30m1 stop Lisbon Humberto Delgado

$770TAP AIR PORTUGAL

Wed, Oct 14 - Mon, Oct 19

1:55 pm - 7:10 amORD Chicago O'Hare Intl-LHR London Heathrow

11h 15m1 stop Detroit Metropolitan Wayne County

8:40 am - 2:30 pmLHR London Heathrow-ORD Chicago O'Hare Intl

11h 50m1 stop Amsterdam Schiphol

$775KLM

Tue, Oct 13 - Tue, Dec 1

7:15 pm - 9:40 pmORD Chicago O'Hare Intl-LHR London Heathrow

20h 25m1 stop Kastrup Copenhagen

10:20 am - 4:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

12h 25m1 stop Kastrup Copenhagen

$780Scandinavian Airlines

Tue, Oct 13 - Wed, Dec 2

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

14h 45m1 stop Kastrup Copenhagen

7:30 pm - 4:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

27h 15m1 stop Kastrup Copenhagen

$783Scandinavian Airlines

Thu, Oct 15 - Wed, Oct 21

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

8h 00mnonstop

1:10 pm - 3:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$785British Airways

Wed, Oct 14 - Wed, Oct 21

6:00 pm - 5:45 pmORD Chicago O'Hare Intl-LHR London Heathrow

17h 45m1 stop Lisbon Humberto Delgado

1:45 pm - 12:40 pmLHR London Heathrow-ORD Chicago O'Hare Intl

28h 55m1 stop Lisbon Humberto Delgado

$793TAP AIR PORTUGAL

Thu, Oct 15 - Wed, Oct 21

9:15 pm - 11:15 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mnonstop

3:15 pm - 6:15 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 00mnonstop

$814British Airways

Thu, Oct 15 - Sun, Oct 25

1:55 pm - 7:10 amORD Chicago O'Hare Intl-LHR London Heathrow

11h 15m1 stop Detroit Metropolitan Wayne County

10:50 am - 8:38 pmLHR London Heathrow-ORD Chicago O'Hare Intl

14h 48m1 stop Atlanta Hartsfield-Jackson

$842KLM

Sat, Oct 10 - Wed, Oct 14

7:25 pm - 2:35 pmORD Chicago O'Hare Intl-LGW London Gatwick

13h 10m1 stop Reykjavik Keflavik Intl

3:40 pm - 9:25 pmLGW London Gatwick-ORD Chicago O'Hare Intl

11h 45m1 stop Reykjavik Keflavik Intl

$874Icelandair

Mon, Oct 12 - Mon, Oct 19

7:25 pm - 2:40 pmORD Chicago O'Hare Intl-LGW London Gatwick

13h 15m1 stop Reykjavik Keflavik Intl

3:40 pm - 6:15 pmLGW London Gatwick-ORD Chicago O'Hare Intl

32h 35m1 stop Reykjavik Keflavik Intl

$1,397Icelandair

Thu, Mar 18 - Mon, Mar 29

10:50 pm - 11:35 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

1:10 pm - 3:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$812British Airways

Thu, Mar 25 - Sun, Apr 4

10:50 pm - 11:35 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

3:15 pm - 6:15 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 00mnonstop

$813British Airways

Wed, Jan 6 - Wed, Jan 13

9:50 pm - 11:35 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

$865Iberia

Wed, Jan 6 - Tue, Jan 12

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

7h 45mnonstop

4:30 pm - 7:15 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$865Iberia

Tue, Jan 5 - Tue, Jan 12

9:50 pm - 11:35 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

12:35 pm - 3:30 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 55mnonstop

$865Finnair

Wed, Jan 6 - Wed, Feb 17

8:40 pm - 10:25 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

3:40 pm - 6:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 05mnonstop

$865Finnair

Tue, Jan 5 - Tue, Jan 12

9:50 pm - 11:35 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

12:35 pm - 3:30 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 55mnonstop

$891American Airlines

Tue, Mar 16 - Wed, Mar 24

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

7h 45mnonstop

11:15 am - 3:10 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 55mnonstop

$892American Airlines

Tue, Jan 5 - Tue, Jan 12

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

8h 10mnonstop

10:25 am - 1:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 20mnonstop

$892United Airlines

Wed, Jan 6 - Thu, Jan 14

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

8h 10mnonstop

10:25 am - 1:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 20mnonstop

$892United Airlines

Low season	February
High season	March
Cheapest flight	$320

Best time to beat the crowds with an average 21% drop in price.

Most popular time to fly and prices are also 17% lower on average.

Flight from Chicago O'Hare Airport to London Heathrow Airport

JKFlew with American Airlines-Sep 2026

Ask ahead of time, if the aircraft can provide AC and/or oxygen to passengers after boarding.

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

Eastbourne

Ilford

Guildford

Kingston upon Thames

Bedford

Crawley

Watford

Harrow

Twickenham

Ipswich

St. Albans

Folkestone

Colchester

Woodbridge

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Car rentals in London

$320 Find Cheap Flights from Illinois to London - Compare and Save

Cheap Flights from Illinois to London

Cheap flights from Illinois to London with top airlines, updated regularly. Compare round-trip, one-way, direct and last-minute deals.

Good to know

Low season

High season

Cheapest flight

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?

More options for your flight to London

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

Cabin class types available on flights to Illinois

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Flights from domestic origins to London

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Find deals for your return flight