$279 Find Cheap Flights from Illinois to London - Compare and Save

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight to London departing on 1/17. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

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Flight Deals

Cheap Flights from Illinois to London

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Illinois to London that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Illinois to London

Fri, Oct 23 - Tue, Nov 3
Multiple Airlines Logo
8:34 pm - 10:00 amSTL  Lambert-St Louis-LGW London Gatwick
31h 26m1 stop Orlando
Multiple Airlines Logo
10:10 am - 9:40 amLGW  London Gatwick-STL Lambert-St Louis
53h 30m2 stops Orlando Atlanta Hartsfield-Jackson
$588Multiple Airlines
Fri, Oct 23 - Tue, Nov 3
Multiple Airlines Logo
8:34 pm - 10:00 amSTL  Lambert-St Louis-LGW London Gatwick
31h 26m1 stop Orlando
Multiple Airlines Logo
10:10 am - 9:40 amLGW  London Gatwick-STL Lambert-St Louis
53h 30m2 stops Orlando Atlanta Hartsfield-Jackson
$610Multiple Airlines
Fri, Nov 13 - Mon, Nov 16
Scandinavian Airlines Logo
7:15 pm - 8:55 amORD  Chicago O'Hare Intl-LHR London Heathrow
31h 40m2 stops Kastrup Copenhagen Stockholm Arlanda
Scandinavian Airlines Logo
6:40 am - 4:45 pmLHR  London Heathrow-ORD Chicago O'Hare Intl
16h 05m1 stop Kastrup Copenhagen
$668Scandinavian Airlines
Sat, Nov 14 - Mon, Nov 16
Scandinavian Airlines Logo
7:15 pm - 9:20 amORD  Chicago O'Hare Intl-LHR London Heathrow
32h 05m1 stop Kastrup Copenhagen
Scandinavian Airlines Logo
9:05 pm - 4:45 pmLHR  London Heathrow-ORD Chicago O'Hare Intl
25h 40m2 stops Stockholm Arlanda Kastrup Copenhagen
$672Scandinavian Airlines
Thu, Sep 24 - Thu, Oct 1
TAP AIR PORTUGAL Logo
6:00 pm - 6:50 pmORD  Chicago O'Hare Intl-LHR London Heathrow
18h 50m1 stop Lisbon Humberto Delgado
TAP AIR PORTUGAL Logo
7:50 pm - 4:00 pmLHR  London Heathrow-ORD Chicago O'Hare Intl
26h 10m1 stop Lisbon Humberto Delgado
$679TAP AIR PORTUGAL
Thu, Sep 24 - Thu, Oct 1
TAP AIR PORTUGAL Logo
6:00 pm - 6:50 pmORD  Chicago O'Hare Intl-LHR London Heathrow
18h 50m1 stop Lisbon Humberto Delgado
TAP AIR PORTUGAL Logo
7:50 pm - 4:00 pmLHR  London Heathrow-ORD Chicago O'Hare Intl
26h 10m1 stop Lisbon Humberto Delgado
$681TAP AIR PORTUGAL
Fri, Sep 25 - Fri, Oct 2
Icelandair Logo
10:25 pm - 11:55 amORD  Chicago O'Hare Intl-LHR London Heathrow
31h 30m1 stop Reykjavik Keflavik Intl
Icelandair Logo
1:05 pm - 9:25 pmLHR  London Heathrow-ORD Chicago O'Hare Intl
14h 20m1 stop Reykjavik Keflavik Intl
$682Icelandair
Thu, Jan 21 - Thu, Jan 28
Icelandair Logo
6:30 pm - 10:50 amORD  Chicago O'Hare Intl-LHR London Heathrow
10h 20m1 stop Reykjavik Keflavik Intl
Icelandair Logo
12:15 pm - 5:20 pmLHR  London Heathrow-ORD Chicago O'Hare Intl
11h 05m1 stop Reykjavik Keflavik Intl
$686Icelandair
Sun, Nov 15 - Tue, Nov 17
United Airlines Logo
5:45 pm - 7:55 amORD  Chicago O'Hare Intl-LHR London Heathrow
8h 10mnonstop
United Airlines Logo
6:50 am - 12:10 pmLHR  London Heathrow-ORD Chicago O'Hare Intl
11h 20m1 stop Brussels Bruxelles-National
$722United Airlines
Tue, Nov 24 - Thu, Nov 26
United Airlines Logo
5:45 pm - 7:55 amORD  Chicago O'Hare Intl-LHR London Heathrow
8h 10mnonstop
United Airlines Logo
6:50 am - 12:10 pmLHR  London Heathrow-ORD Chicago O'Hare Intl
11h 20m1 stop Brussels Bruxelles-National
$722United Airlines
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Good to know

Low season

February

Cheapest flight

$279
Best time to beat the crowds with an average 17% drop in price.
Most popular time to fly and prices are also 14% lower on average.
Flight from St. Louis to London Gatwick Airport

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

Insights shared by verified travelers who flew the route from Illinois to London 
Learn how KAYAK collects reviews and tips from users.
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.

FAQs for booking flights from Illinois to London

  • 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.

Traveling to a place near London?

Book flights to London if you plan to visit one of these locations
Hounslow
Hayes
Slough
Richmond
Wembley
Luton
Eastbourne
Ilford
Crawley
Watford
Bedford
Colchester
Ipswich
Guildford
Kingston upon Thames
Twickenham
St. Albans
Harrow
Newbury
Maidenhead

Everything you need to know for your flight to London

Cabin class types available on flights to Illinois

Cabin classes available on flights to London. Prices are the lowest found on KAYAK over the last 7 days. Price and availability is not guaranteed.
First Class flights to Londonfrom $4,323
Business Class flights to Londonfrom $3,869
Premium Economy Class flights to Londonfrom $1,721
Economy Class flights to Londonfrom $840