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Cheap flights from Illinois to London Heathrow Airport from £237

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 4/8. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — LHR
23 Jul — 30 Jul1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Illinois to Heathrow

Enter your travel dates to find the best prices.

Cheapest flights from Illinois to Heathrow
Explore the most affordable flight options available from Illinois to Heathrow. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 23 June 2026.

Tue 10/1110:35
MLI
-
LHR
1 stop15h 20m
United Airlines
Thu 12/1106:50
LHR
-
MLI
2 stops14h 17m
United Airlines
Deal found 21/6£556
Tue 27/1019:14
PIA
-
LHR
1 stop31h 41m
United Airlines
Fri 30/1006:50
LHR
-
PIA
2 stops20h 58m
United Airlines
Deal found 22/6£556
Fri 17/717:43
PIA
-
LHR
1 stop32h 47m
Lufthansa
Tue 25/806:50
LHR
-
PIA
2 stops18h 13m
Lufthansa
Deal found 21/6£619
Mon 28/912:08
BMI
-
LHR
1 stop12h 17m
Virgin Atlantic
Sun 4/1017:35
LHR
-
BMI
2 stops28h 04m
Virgin Atlantic
Deal found 18/6£623
Fri 4/915:44
MLI
-
LHR
1 stop33h 01m
United Airlines
Sun 13/906:50
LHR
-
MLI
2 stops33h 17m
United Airlines
Deal found 21/6£653
Sun 23/815:35
PIA
-
LHR
1 stop14h 20m
United Airlines
Tue 15/906:50
LHR
-
PIA
2 stops20h 09m
United Airlines
Deal found 22/6£653
Wed 12/805:45
PIA
-
LHR
1 stop20h 45m
United Airlines
Wed 19/807:25
LHR
-
PIA
2 stops17h 38m
United Airlines
Deal found 22/6£654
Sun 6/913:15
MLI
-
LHR
2 stops14h 45m
United Airlines
Sun 13/906:50
LHR
-
MLI
2 stops18h 41m
United Airlines
Deal found 21/6£655
Wed 23/908:13
MLI
-
LHR
2 stops16h 42m
United Airlines
Wed 30/906:50
LHR
-
MLI
2 stops18h 13m
United Airlines
Deal found 23/6£656
Wed 19/808:13
MLI
-
LHR
2 stops15h 42m
United Airlines
Fri 28/807:25
LHR
-
MLI
2 stops16h 20m
United Airlines
Deal found 22/6£657
Mon 14/918:39
PIA
-
LHR
2 stops15h 01m
United Airlines
Sat 19/906:50
LHR
-
PIA
2 stops14h 07m
United Airlines
Deal found 21/6£659
Wed 23/911:19
MLI
-
LHR
1 stop18h 01m
Delta
Wed 30/909:55
LHR
-
MLI
2 stops18h 35m
Delta
Deal found 22/6£660

Find flight deals from Illinois to Heathrow

Keep the following information in mind while searching for Illinois to Heathrow flight deals. Data was last updated 23 June 2026.

Round-trip from

£556

One-way from

£237

Popular in

June

Cheapest in

September

Average price

£1,039

Good round-trip deal

£696 or less

Good one-way deal

£400 or less
United Airlines
  • United Airlines
  • 10/11-12/11
  • 3 total stops
  • 29h 37m total
  • Illinois to London
Search Deals
4/8
  • 4/8
  • 1 total stop
  • 12h 20m total
  • Illinois to London
Search Deals
Highest demand for flights based on searches. 26% potential increase in price (£161 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 7% potential price decrease (£30 potential savings vs. average return price).
Search Deals
Average for round-trip flights in June 2026
Search Deals
Price to beat on a round-trip flight from Illinois to London Heathrow.
Search Deals
Price to beat on a one-way flight from Illinois to London Heathrow.
Search Deals

Cheapflights Fare Finder

 
Customise your flight search to find flights from Illinois to Heathrow 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 23 June 2026.
Use the filters below to find and compare flights from Illinois to London Heathrow Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

MolineLondon

MLI - LHR

MLILHR

Moline Quad-City

Tue 10/11

10:35-07:55

1 stop15h 20m

London Heathrow

Thu 12/11

06:50-15:07

2 stops14h 17m

£556

MolineLondon

MLI - LHR

MLILHR

Moline Quad-City

Wed 23/9

08:13-11:55

1 stop21h 42m

London Heathrow

Wed 30/9

06:50-22:38

2 stops21h 48m

£653

MolineLondon

MLI - LHR

MLILHR

Moline Quad-City

Fri 4/9

15:44-06:45

1 stop33h 01m

London Heathrow

Sun 13/9

06:50-10:07

2 stops33h 17m

£653

PeoriaLondon

PIA - LHR

PIALHR

Greater Peoria

Sun 23/8

15:35-11:55

1 stop14h 20m

London Heathrow

Tue 15/9

06:50-20:59

2 stops20h 09m

£653

PeoriaLondon

PIA - LHR

PIALHR

Greater Peoria

Wed 12/8

05:45-08:30

1 stop20h 45m

London Heathrow

Wed 19/8

07:25-19:03

2 stops17h 38m

£654

MolineLondon

MLI - LHR

MLILHR

Moline Quad-City

Wed 19/8

08:13-05:55

2 stops15h 42m

London Heathrow

Fri 28/8

07:25-17:45

2 stops16h 20m

£657

MolineLondon

MLI - LHR

MLILHR

Moline Quad-City

Wed 23/9

11:19-11:20

1 stop18h 01m

London Heathrow

Wed 30/9

09:55-22:30

2 stops18h 35m

£660

EvansvilleLondon

EVV - LHR

EVVLHR

Evansville Dress Regional

Tue 20/10

10:05-06:25

1 stop14h 20m

London Heathrow

Fri 30/10

11:45-09:25

2 stops26h 40m

£662

MolineLondon

MLI - LHR

MLILHR

Moline Quad-City

Mon 30/11

11:00-07:50

1 stop14h 50m

London Heathrow

Tue 8/12

08:40-22:30

2 stops19h 50m

£662

EvansvilleLondon

EVV - LHR

EVVLHR

Evansville Dress Regional

Wed 21/10

17:45-11:20

1 stop11h 35m

London Heathrow

Fri 30/10

10:45-22:03

1 stop16h 18m

£684

Flights are sorted by cheapest return flights first.

Deals found on 22/6

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

Have a flexible travel schedule? Discover the best time to fly to Heathrow 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 Heathrow Airport

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

Currently, October is the cheapest month in which you can book a flight from Illinois to London Heathrow Airport (average of £83). Flying from Illinois to London Heathrow Airport in September is currently the most expensive (average of £1,409). 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 LHR?

Find hourly flight availability from Illinois to Heathrow. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 23 June 2026.

When flying from Illinois to London Heathrow Airport, 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 Heathrow Airport

Explore weekly flight availability from Illinois to Heathrow. 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 23 June 2026.

The most flights from USIL to LHR are scheduled on a Monday (56 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (44 on average).

How much does it cost for a return flight from Illinois to London Heathrow Airport?

How far ahead should I book a flight from Illinois to London Heathrow Airport?

The price you pay for your flight from Illinois to London Heathrow Airport may vary depending on when you book. For the best chance of a lower fare, look to book 42 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

Related info for your journey

Find useful and relevant information for your journey from Illinois to Heathrow. 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 Heathrow Airport?

    For as low as £684, United Airlines can have you in London Heathrow Airport from Illinois in 11h 35m. The distance from Illinois to London Heathrow Airport is about 4111 mi. This flight may include one or multiple stops.

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

    The cheapest airline one-way is TAP AIR PORTUGAL, with whom users have recently found tickets for as low as £167. However, be on the lookout for offers from Lufthansa and British Airways, as they are both options that can get you from Illinois to London Heathrow Airport for a low price.

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

    The most popular route from Illinois to London Heathrow Airport is Chicago O'Hare Intl - London Heathrow. You may also consider Chicago Midway - London Heathrow or Lambert-St Louis - London Heathrow.

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

    No one likes to see their flight delayed. When booking a flight from Illinois to London Heathrow Airport consider choosing Air Canada (72%), Austrian Airlines (72%) or United Airlines (72%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Illinois to London Heathrow Airport?

    On average you can expect to pay £706 for a flight from Illinois to London Heathrow Airport. The cheapest flight overall is £234 while the most popular route, (Chicago O'Hare Intl - London Heathrow) is currently priced at £466.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Illinois to Heathrow 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 Heathrow Airport?

    Currently, October is the cheapest month in which you can book a flight from Illinois to London Heathrow Airport (average of £83). Flying from Illinois to London Heathrow Airport in September is currently the most expensive (average of £1,409). 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 Heathrow Airport?

Book flights to London Heathrow Airport if you plan to visit one of these locations
Hounslow
Milton Keynes
Wembley
Luton
Gatwick
Croydon
Ilford
Slough
Hayes
Brentford
Colchester
Northampton
Kingston upon Thames
Swindon
Eastbourne
Watford
Poole
Southall
Romford
Ipswich

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Alternative routes for Illinois to Heathrow

See prices for flight routes from nearby airports that may be better suited for you.
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O'Hare Intl to Gatwick flights
San Francisco to Gatwick flights
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Top 5 airlines flying from Illinois to Heathrow

Discover the top 5 airlines that operate flights from Illinois to Heathrow. 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 23 June 2026.
AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapest£370Average£495FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
British AirwaysCheapest£403Average£561FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Aer LingusCheapest£466Average£760FlexibilityNo cancel feeOn-timeN/A
Search Aer Lingus flights
United AirlinesCheapest£515Average£706FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
IberiaCheapest£526Average£674FlexibilityNo 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 Heathrow?

When you search for this flight from Illinois to Heathrow, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

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

By finding flights from multiple airlines and providers at completely no cost, Cheapflights helps millions of users like you annually find the best flights to Heathrow from Illinois.

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

Cheapflights does show flights with no change fees to all users. To see these options for flights from Illinois to Heathrow, users can toggle the no change fees filter when performing a flight search.

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

Yes, Cheapflights offers price alerts on Illinois to Heathrow 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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