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Cheap flights from Illinois to London from £243

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/5. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — LON
10 Apr — 17 Apr1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Illinois to London

Enter your travel dates to find the best prices.

Cheapest flights from Illinois to London
Explore the most affordable flight options available from Illinois to London. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 11 March 2026.

Wed 22/418:00
ORD
-
LHR
1 stop18h 50m
TAP AIR PORTUGAL
Tue 5/519:50
LHR
-
ORD
1 stop26h 10m
TAP AIR PORTUGAL
Deal found 6/3£424
Sun 27/922:25
ORD
-
LGW
1 stop10h 15m
Icelandair
Sun 4/1015:40
LGW
-
ORD
1 stop32h 35m
Icelandair
Deal found 5/3£424
Sun 12/419:25
ORD
-
STN
2 stops21h 55m
Multiple Airlines
Fri 17/406:20
STN
-
ORD
2 stops17h 55m
Multiple Airlines
Deal found 9/3£424
Mon 20/419:15
ORD
-
LHR
1 stop14h 45m
Scandinavian Airlines
Sat 25/406:40
LHR
-
ORD
1 stop15h 30m
Scandinavian Airlines
Deal found 8/3£425
Mon 20/419:25
ORD
-
LGW
1 stop13h 15m
Icelandair
Fri 24/415:40
LGW
-
ORD
1 stop11h 45m
Icelandair
Deal found 8/3£425
Mon 27/419:15
ORD
-
LHR
1 stop14h 45m
Scandinavian Airlines
Fri 1/506:40
LHR
-
ORD
1 stop15h 30m
Scandinavian Airlines
Deal found 8/3£426
Mon 20/419:25
ORD
-
STN
3 stops21h 55m
Multiple Airlines
Mon 27/422:45
STN
-
ORD
2 stops26h 40m
Multiple Airlines
Deal found 5/3£426
Tue 3/1118:30
ORD
-
LHR
1 stop10h 20m
Icelandair
Wed 11/1112:15
LHR
-
ORD
1 stop11h 05m
Icelandair
Deal found 8/3£426
Mon 13/419:25
ORD
-
LGW
1 stop13h 15m
Icelandair
Tue 28/415:40
LGW
-
ORD
1 stop32h 35m
Icelandair
Deal found 6/3£426
Mon 13/419:25
ORD
-
STN
2 stops22h 55m
Multiple Airlines
Wed 15/422:45
STN
-
ORD
2 stops25h 05m
Multiple Airlines
Deal found 5/3£426
Fri 18/919:25
ORD
-
LGW
1 stop13h 15m
Icelandair
Sat 26/915:40
LGW
-
ORD
1 stop32h 35m
Icelandair
Deal found 9/3£427
Fri 10/419:25
ORD
-
STN
2 stops23h 25m
Multiple Airlines
Thu 30/408:15
STN
-
ORD
2 stops15h 35m
Multiple Airlines
Deal found 5/3£427

Find flight deals from Illinois to London

Keep the following information in mind while searching for Illinois to London flight deals. Data was last updated 11 March 2026.

Round-trip from

£424

One-way from

£243

Popular in

June

Cheapest in

February

Average price

£524

Good round-trip deal

£558 or less

Good one-way deal

£287 or less
TAP AIR PORTUGAL
  • TAP AIR PORTUGAL
  • 22/4-29/4
  • 2 total stops
  • 32h 50m total
  • Illinois to London
Search Deals
9/5
  • 9/5
  • 2 total stops
  • 31h 47m total
  • Illinois to London
Search Deals
Highest demand for flights based on searches. 21% potential increase in price (£112 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease (£21 potential savings vs. average return price).
Search Deals
Average for round-trip flights in March 2026
Search Deals
Price to beat on a round-trip flight from Illinois to London (LON).
Search Deals
Price to beat on a one-way flight from Illinois to London (LON).
Search Deals

Cheapflights Fare Finder

 
Customise your flight search to find flights from Illinois to London that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 11 March 2026.
Use the filters below to find and compare flights from Illinois to London that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

ChicagoLondon

ORD - LTN

ORDLTN

Chicago O'Hare Intl

Tue 7/4

19:25-22:10

2 stops20h 45m

London Luton

Tue 14/4

09:40-18:15

2 stops14h 35m

£471

ChicagoLondon

ORD - LTN

ORDLTN

Chicago O'Hare Intl

Wed 6/5

19:25-16:35

2 stops15h 10m

London Luton

Wed 13/5

06:15-18:15

2 stops18h 00m

£479

ChicagoLondon

ORD - LTN

ORDLTN

Chicago O'Hare Intl

Fri 1/5

21:00-17:25

1 stop14h 25m

London Luton

Thu 7/5

13:00-19:15

1 stop12h 15m

£484

ChicagoLondon

ORD - LGW

ORDLGW

Chicago O'Hare Intl

Mon 23/3

12:05-06:00

1 stop12h 55m

London Gatwick

Wed 13/5

14:00-09:05

1 stop25h 05m

£488

ChicagoLondon

ORD - LHR

ORDLHR

Chicago O'Hare Intl

Mon 17/8

17:00-06:50

Nonstop7h 50m

London Heathrow

Tue 25/8

14:45-17:35

Nonstop8h 50m

£505

ChicagoLondon

MDW - LHR

MDWLHR

Chicago Midway

Mon 23/3

09:35-06:50

2 stops16h 15m

London Heathrow

Tue 31/3

06:15-17:22

2 stops17h 07m

£533

ChicagoLondon

ORD - STN

ORDSTN

Chicago O'Hare Intl

Mon 13/4

20:10-16:50

1 stop38h 40m

London Stansted

Thu 23/4

17:35-09:40

1 stop22h 05m

£533

St. LouisLondon

STL - LHR

STLLHR

Lambert-St Louis

Mon 13/4

13:46-07:10

1 stop11h 24m

London Heathrow

Tue 28/4

09:55-21:19

2 stops17h 24m

£539

St. LouisLondon

STL - LHR

STLLHR

Lambert-St Louis

Mon 30/3

17:25-13:05

1 stop13h 40m

London Heathrow

Fri 10/4

06:30-17:05

2 stops16h 35m

£539

St. LouisLondon

STL - LHR

STLLHR

Lambert-St Louis

Tue 21/4

13:46-07:10

1 stop11h 24m

London Heathrow

Thu 30/4

08:40-20:44

2 stops18h 04m

£539

Flights are sorted by cheapest return flights first.

Deals found on 10/3

Showing 1-10 of 60 resultsSorted by cheapest first
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Best time to book a flight from Illinois to London

Have a flexible travel schedule? Discover the best time to fly to London from Illinois with our price prediction graph.
Estimated return price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Illinois to London

What is the cheapest month to book a flight from Illinois to London?

Currently, June is the cheapest month in which you can book a flight from Illinois to London (average of £46). Flying from Illinois to London in July is currently the most expensive (average of £451). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from IL to LON?

Find hourly flight availability from Illinois to London. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 11 March 2026.

When flying from Illinois to London, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Weekly flight availability from Illinois to London

Explore weekly flight availability from Illinois to London. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated 11 March 2026.

The most flights from USIL to LON are scheduled on a Monday (45 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (45 on average).

Related info for your journey

Find useful and relevant information for your journey from Illinois to London. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Illinois to London?

    Departing from Illinois to London will take you 7h 50m. Illinois and London are separated by a distance of 3939 mi. This flight may include one or multiple stops.

  • What are the cheapest airlines to fly from Illinois to London one-way?

    £165 is the cheapest one-way deal found within the past few days, from TAP AIR PORTUGAL. You may also be able to find cheap deals on Lufthansa and British Airways, with prices starting from £275 and £281, respectively.

  • What are the most popular routes from Illinois to London?

    When deciding which route to take from Illinois to London consider Chicago O'Hare Intl - London Heathrow, Chicago O'Hare Intl - London Gatwick or Chicago O'Hare Intl - London City as they are the most popular.

  • What are the most reliable airlines from Illinois to London?

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Illinois to London on time: Aer Lingus (76%), Air Canada (73%), Austrian Airlines (73%).

  • What are the cheapest flights from Illinois to London?

    Looking for the cheapest flight from Illinois to London? While on average our users pay £668, our data indicates the cheapest price to be £229. The most popular route (Chicago O'Hare Intl - London Heathrow), is priced around £354.

  • Can I find deals for flights from Illinois to London that include hotel bookings?

    Yes. In addition to deals on Illinois to London flights, Cheapflights offers holiday packages that include both flights and hotel.

  • How can I find direct flights from Illinois to London?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Illinois to London.

  • Can I find deals for business class flights from Illinois to London?

    Yes. Cheapflights offers flight deals from Illinois to London by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Illinois to London?

    Currently, June is the cheapest month in which you can book a flight from Illinois to London (average of £46). Flying from Illinois to London in July is currently the most expensive (average of £451). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Travelling to a place near London?

Book flights to London if you plan to visit one of these locations
Milton Keynes
Wembley
Croydon
Luton
Hounslow
Slough
Gatwick
Ilford
Hayes
Brentford
Colchester
Guildford
Watford
Kingston upon Thames
Chelmsford
Eastbourne
Ipswich
Bedford
Romford
Southend-on-Sea

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Alternative routes for Illinois to London

See prices for flight routes from nearby airports that may be better suited for you.
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Top 7 airlines flying from Illinois to London

Discover the top 7 airlines that operate flights from Illinois to London. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 11 March 2026.
AirlineCheapestAverageFlexibilityOn-time
LufthansaCheapest£358Average£514FlexibilityNo cancel feeOn-time76%
Search Lufthansa flights
American AirlinesCheapest£385Average£612FlexibilityNo cancel feeOn-time71%
Search American Airlines flights
FinnairCheapest£414Average£562FlexibilityNo cancel feeOn-time76%
Search Finnair flights
British AirwaysCheapest£422Average£586FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Aer LingusCheapest£449Average£580FlexibilityNo cancel feeOn-timeN/A
Search Aer Lingus flights
United AirlinesCheapest£462Average£663FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
IberiaCheapest£484Average£590FlexibilityNo cancel feeOn-time77%
Search Iberia flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travellers can enjoy low prices and a wide availability of flights to their desired destinations.

How does Cheapflights help users find flights from Illinois to London?

Cheapflights helps you search for flights from Illinois to London via 900+ travel sites so you don’t have to. After performing a flight search, users can also filter their flight selection by filtering for price, number of stops, airlines, and so on.

Why should you use Cheapflights to find cheap flight tickets from Illinois to London?

Cheapflights taps into our reliable network of hundreds of airlines and travel agencies to find the best deals for flights from Illinois to London for you. Better yet — we are completely free to use.

Can Cheapflights find flights from Illinois to London with no change fees?

Certainly. Search results for flights to London from Illinois shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

Can Cheapflights notify me if prices for flights from Illinois to London become cheaper?

Yes, Cheapflights offers price alerts on Illinois to London flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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