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.

$230 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

Sun, Oct 18 - Wed, Nov 4

4:30 pm - 10:00 amSTL Lambert-St Louis-LGW London Gatwick

35h 30m1 stop Orlando

10:10 am - 9:40 amLGW London Gatwick-STL Lambert-St Louis

29h 30m2 stops Orlando Atlanta Hartsfield-Jackson

$654Multiple Airlines

Fri, Oct 23 - Thu, Nov 5

6:35 pm - 10:00 amSTL Lambert-St Louis-LGW London Gatwick

33h 25m2 stops Atlanta Hartsfield-Jackson Orlando

11:00 am - 11:16 pmLGW London Gatwick-STL Lambert-St Louis

18h 16m1 stop Orlando

$654Multiple Airlines

Thu, Jan 14 - Mon, Jan 18

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

$659Scandinavian Airlines

Sun, Oct 11 - Wed, Oct 14

7:15 pm - 7:55 pmORD Chicago O'Hare Intl-LHR London Heathrow

42h 40m2 stops Kastrup Copenhagen Stockholm Arlanda

6:40 am - 4:10 pmLHR London Heathrow-ORD Chicago O'Hare Intl

15h 30m1 stop Kastrup Copenhagen

$661Scandinavian Airlines

Sun, Sep 20 - Tue, Sep 29

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

10h 30m1 stop Reykjavik Keflavik Intl

1:05 pm - 6:15 pmLHR London Heathrow-ORD Chicago O'Hare Intl

11h 10m1 stop Reykjavik Keflavik Intl

$679Icelandair

Wed, Nov 18 - Tue, Nov 24

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

$684British Airways

Sun, Sep 20 - Tue, Sep 29

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

18h 50m1 stop Lisbon Humberto Delgado

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

27h 15m1 stop Lisbon Humberto Delgado

$684TAP AIR PORTUGAL

Sun, Sep 20 - Wed, Sep 30

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

18h 50m1 stop Lisbon Humberto Delgado

6:45 pm - 12:40 pmLHR London Heathrow-ORD Chicago O'Hare Intl

23h 55m1 stop Lisbon Humberto Delgado

$686TAP AIR PORTUGAL

Thu, Jan 14 - Mon, Jan 18

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

$687Icelandair

Tue, Nov 17 - Mon, Nov 23

5:10 pm - 6:55 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

$706British Airways

Recent last minute flight deals from Illinois to London

Mon, Aug 24 - Mon, Aug 31

10:25 pm - 8:10 pmORD Chicago O'Hare Intl-LGW London Gatwick

15h 45m2 stops Reykjavik Keflavik Intl Oslo Gardermoen

7:05 pm - 9:25 pmLGW London Gatwick-ORD Chicago O'Hare Intl

32h 20m3 stops Kastrup Copenhagen Oslo Gardermoen Reykjavik Keflavik Intl

$820Multiple Airlines

Fri, Aug 21 - Fri, Aug 28

9:10 pm - 10:00 amORD Chicago O'Hare Intl-LGW London Gatwick

30h 50m1 stop Orlando

2:00 pm - 11:08 pmLGW London Gatwick-ORD Chicago O'Hare Intl

15h 08m1 stop Orlando

$844Multiple Airlines

Sun, Aug 23 - Wed, Sep 2

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

$845TAP AIR PORTUGAL

Sun, Aug 23 - Wed, Sep 2

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

12h 45m1 stop Lisbon Humberto Delgado

7:50 pm - 12:40 pmLHR London Heathrow-ORD Chicago O'Hare Intl

22h 50m1 stop Lisbon Humberto Delgado

$848TAP AIR PORTUGAL

Tue, Aug 25 - Wed, Sep 2

3:45 pm - 8:05 amORD Chicago O'Hare Intl-LHR London Heathrow

10h 20m1 stop Dublin

9:50 am - 8:20 pmLHR London Heathrow-ORD Chicago O'Hare Intl

16h 30m2 stops Dublin Toronto Pearson Intl

$856Aer Lingus

Mon, Aug 24 - Sat, Sep 26

9:00 pm - 1:30 pmORD Chicago O'Hare Intl-LHR London Heathrow

10h 30m1 stop Dublin

9:50 am - 7:30 pmLHR London Heathrow-ORD Chicago O'Hare Intl

15h 40m2 stops Dublin Toronto Pearson Intl

$861Aer Lingus

Mon, Aug 24 - Wed, Sep 9

10:07 am - 9:35 amORD Chicago O'Hare Intl-LHR London Heathrow

17h 28m2 stops New York John F Kennedy Intl Oslo Gardermoen

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

26h 40m1 stop Kastrup Copenhagen

$870Scandinavian Airlines

Tue, Aug 25 - Thu, Sep 10

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

14h 45m1 stop Kastrup Copenhagen

6:40 am - 4:10 pmLHR London Heathrow-ORD Chicago O'Hare Intl

15h 30m1 stop Kastrup Copenhagen

$898Scandinavian Airlines

Sun, Aug 23 - Wed, Sep 2

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

7h 45mnonstop

7:50 am - 4:00 pmLHR London Heathrow-ORD Chicago O'Hare Intl

14h 10m1 stop Madrid Barajas

$933Iberia

Sun, Aug 23 - Wed, Sep 2

8:45 pm - 10:30 amORD Chicago O'Hare Intl-LHR London Heathrow

7h 45mnonstop

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

8h 45mnonstop

$963Iberia

Recent direct flight deals from Illinois to London

Wed, Nov 18 - Tue, Nov 24

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

$684British Airways

Tue, Nov 17 - Mon, Nov 23

5:10 pm - 6:55 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

$706British Airways

Mon, Sep 21 - Tue, Sep 29

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

8h 00mnonstop

9:45 am - 12:25 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 40mnonstop

$840Finnair

Sun, Sep 20 - Tue, Sep 29

8:50 pm - 10:50 amORD Chicago O'Hare Intl-LHR London Heathrow

8h 00mnonstop

12:15 pm - 2:55 pmLHR London Heathrow-ORD Chicago O'Hare Intl

8h 40mnonstop

$847Finnair

Tue, Oct 27 - Mon, Nov 2

10:50 pm - 11:35 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

$850Iberia

Mon, Nov 16 - Thu, Nov 26

9:50 pm - 11:35 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

$855Iberia

Wed, Oct 14 - Wed, Oct 21

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

8h 20mnonstop

2:10 pm - 5:25 pmLHR London Heathrow-ORD Chicago O'Hare Intl

9h 15mnonstop

$877Lufthansa

Sun, Nov 15 - Tue, Nov 24

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

$882Lufthansa

Wed, Nov 18 - Wed, Nov 25

3:45 pm - 5:55 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

$882United Airlines

Tue, Nov 24 - Fri, Nov 27

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

8h 10mnonstop

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

9h 20mnonstop

$882United Airlines

Useful Info

Low season	February
High season	March
Cheapest flight	$230

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

Most popular time to fly and prices are also 18% 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

Hayes

Slough

Richmond

Wembley

Luton

Eastbourne

Ilford

Crawley

Bedford

Watford

Guildford

Colchester

Kingston upon Thames

Ipswich

Twickenham

St. Albans

Harrow

Newbury

Maidenhead

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 $4,323

Business Class flights to Londonfrom $3,869

Premium Economy Class flights to Londonfrom $1,710

Economy Class flights to Londonfrom $840

$230 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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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?

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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Choose which airport to fly into in London

Find deals for your return flight