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.

$217 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

Sat, Dec 5 - Tue, Dec 8

6:05 pm - 8:15 amSTL Lambert-St Louis-LGW London Gatwick

32h 10m1 stop Orlando

9:35 am - 12:41 amLGW London Gatwick-STL Lambert-St Louis

21h 06m1 stop Orlando

$587Multiple Airlines

Thu, Dec 3 - Tue, Dec 8

6:05 pm - 10:00 amSTL Lambert-St Louis-LGW London Gatwick

33h 55m1 stop Orlando

9:35 am - 12:41 amLGW London Gatwick-STL Lambert-St Louis

21h 06m1 stop Orlando

$587Multiple Airlines

Tue, Oct 27 - Mon, Nov 16

7:30 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

11h 05m1 stop Reykjavik Keflavik Intl

$706Icelandair

Sun, Nov 1 - Sat, Nov 14

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

11h 05m1 stop Reykjavik Keflavik Intl

$706Icelandair

Mon, Nov 23 - Thu, Nov 26

7:15 pm - 9:20 amORD Chicago O'Hare Intl-LHR London Heathrow

32h 05m1 stop Kastrup Copenhagen

6:40 am - 4:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

16h 05m2 stops Stockholm Arlanda Kastrup Copenhagen

$706Scandinavian Airlines

Sat, Oct 31 - Wed, Nov 11

8:15 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

$707Scandinavian Airlines

Wed, Nov 18 - Wed, Nov 25

7:00 pm - 6:55 pmORD Chicago O'Hare Intl-LHR London Heathrow

17h 55m1 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

Sat, Oct 17 - Fri, Oct 30

6:05 pm - 5:45 pmORD Chicago O'Hare Intl-LHR London Heathrow

17h 40m1 stop Lisbon Humberto Delgado

6:00 am - 4:30 pmLHR London Heathrow-ORD Chicago O'Hare Intl

15h 30m1 stop Lisbon Humberto Delgado

$709TAP AIR PORTUGAL

Fri, Nov 20 - Sat, Nov 28

12:50 pm - 8:30 amORD Chicago O'Hare Intl-LHR London Heathrow

13h 40m1 stop Toronto Pearson Intl

1:00 pm - 7:52 pmLHR London Heathrow-ORD Chicago O'Hare Intl

12h 52m1 stop Montreal Pierre Elliott Trudeau Intl

$711Air Canada

Sat, Nov 21 - Sun, Nov 29

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

11h 15m1 stop Montreal Pierre Elliott Trudeau Intl

11:10 am - 7:58 pmLHR London Heathrow-ORD Chicago O'Hare Intl

14h 48m1 stop Toronto Pearson Intl

$713Air Canada

Recent last minute flight deals from Illinois to London

Mon, Sep 7 - Wed, Sep 9

11:22 am - 7:50 amSTL Lambert-St Louis-LHR London Heathrow

14h 28m1 stop Philadelphia

7:50 am - 8:20 amLHR London Heathrow-STL Lambert-St Louis

30h 30m2 stops Madrid Barajas Boston Logan Intl

$726Iberia

Mon, Sep 7 - Wed, Sep 9

3:45 pm - 9:50 amORD Chicago O'Hare Intl-STN London Stansted

12h 05m1 stop Dublin

1:10 pm - 7:15 pmSTN London Stansted-ORD Chicago O'Hare Intl

12h 05m1 stop Dublin

$788Multiple Airlines

Mon, Sep 7 - Wed, Sep 9

3:45 pm - 9:15 amORD Chicago O'Hare Intl-LTN London Luton

11h 30m1 stop Dublin

6:15 am - 2:00 pmLTN London Luton-ORD Chicago O'Hare Intl

13h 45m1 stop Dublin

$788Multiple Airlines

Thu, Sep 10 - Tue, Sep 15

6:00 pm - 9:45 amORD Chicago O'Hare Intl-LGW London Gatwick

33h 45m1 stop Lisbon Humberto Delgado

4:25 pm - 4:00 pmLGW London Gatwick-ORD Chicago O'Hare Intl

29h 35m1 stop Lisbon Humberto Delgado

$827TAP AIR PORTUGAL

Thu, Sep 10 - Wed, Sep 16

6:00 pm - 9:45 amORD Chicago O'Hare Intl-LGW London Gatwick

33h 45m1 stop Lisbon Humberto Delgado

4:25 pm - 12:40 pmLGW London Gatwick-ORD Chicago O'Hare Intl

26h 15m1 stop Lisbon Humberto Delgado

$827TAP AIR PORTUGAL

Tue, Sep 8 - Tue, Sep 15

1:25 pm - 8:05 amSTL Lambert-St Louis-LHR London Heathrow

12h 40m1 stop Chicago O'Hare Intl

10:50 am - 8:20 amLHR London Heathrow-STL Lambert-St Louis

27h 30m2 stops Madrid Barajas Boston Logan Intl

$864Iberia

Wed, Sep 9 - Wed, Sep 16

1:40 pm - 1:15 pmSTL Lambert-St Louis-LHR London Heathrow

17h 35m1 stop Atlanta Hartsfield-Jackson

6:30 am - 5:40 pmLHR London Heathrow-STL Lambert-St Louis

17h 10m2 stops Amsterdam Schiphol Atlanta Hartsfield-Jackson

$867Delta

Tue, Sep 8 - Thu, Sep 10

1:40 pm - 7:15 amSTL Lambert-St Louis-LHR London Heathrow

11h 35m1 stop Atlanta Hartsfield-Jackson

9:55 am - 7:58 pmLHR London Heathrow-STL Lambert-St Louis

16h 03m2 stops Amsterdam Schiphol Atlanta Hartsfield-Jackson

$867Delta

Tue, Sep 8 - Thu, Sep 10

9:00 pm - 1:55 pmORD Chicago O'Hare Intl-LHR London Heathrow

10h 55m1 stop Dublin

12:00 pm - 7:15 pmLHR London Heathrow-ORD Chicago O'Hare Intl

13h 15m1 stop Dublin

$869Aer Lingus

Mon, Sep 7 - Wed, Sep 16

9:00 pm - 1:55 pmORD Chicago O'Hare Intl-LHR London Heathrow

10h 55m1 stop Dublin

1:25 pm - 7:15 pmLHR London Heathrow-ORD Chicago O'Hare Intl

11h 50m1 stop Dublin

$890Aer Lingus

Recent direct flight deals from Illinois to London

Thu, Oct 22 - Sat, Oct 24

5:00 pm - 6:50 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 50mnonstop

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

8h 45mnonstop

$718British Airways

Tue, Oct 20 - Thu, Oct 29

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

8h 00mnonstop

11:00 am - 2:45 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$719British Airways

Tue, Oct 20 - Tue, Nov 3

6:05 pm - 8:05 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mnonstop

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

9h 05mnonstop

$832Finnair

Sun, Oct 4 - Tue, Oct 13

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

8h 00mnonstop

9:45 am - 12:30 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 45mnonstop

$832Finnair

Tue, Dec 8 - Thu, Dec 10

6:50 pm - 8:35 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

$856Iberia

Wed, Feb 3 - Wed, Feb 24

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

$864Iberia

Wed, Jan 13 - Mon, Jan 18

6:50 pm - 8:35 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

$880Multiple Airlines

Wed, Dec 9 - Wed, Dec 23

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

$882United Airlines

Wed, Dec 9 - Wed, Dec 16

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

$882United Airlines

Mon, Feb 1 - Mon, Feb 8

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

7h 45mnonstop

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

9h 20mnonstop

$893Multiple Airlines

Useful Info

Low season	February
High season	March
Cheapest flight	$217

Best time to beat the crowds with an average 20% drop in price.

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

Flight from St. Louis to London Gatwick 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

Slough

Hayes

Richmond

Wembley

Luton

Ilford

Eastbourne

Crawley

Guildford

Bedford

Colchester

Ipswich

Watford

Kingston upon Thames

Twickenham

St. Albans

Harrow

Newbury

Maidenhead

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$217 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

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