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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 15/9. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — LHR
25 Jun — 2 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 26 May 2026.

Tue 17/1113:33
CMI
-
LHR
1 stop14h 52m
Iberia
Tue 24/1106:05
LHR
-
CMI
2 stops19h 20m
Iberia
Deal found 25/5£639
Tue 1/910:05
EVV
-
LHR
1 stop15h 10m
Delta
Tue 29/908:40
LHR
-
EVV
2 stops19h 23m
Delta
Deal found 21/5£649
Wed 23/905:55
MLI
-
LHR
1 stop18h 30m
Delta
Wed 30/908:40
LHR
-
MLI
2 stops19h 50m
Delta
Deal found 22/5£649
Sun 23/806:00
BMI
-
LHR
1 stop18h 25m
Delta
Tue 15/908:40
LHR
-
BMI
2 stops19h 42m
Delta
Deal found 21/5£649
Wed 21/1017:45
EVV
-
LHR
1 stop11h 35m
KLM
Thu 5/1106:30
LHR
-
EVV
2 stops16h 24m
KLM
Deal found 25/5£650
Wed 23/905:55
MLI
-
LHR
1 stop18h 30m
KLM
Wed 30/906:30
LHR
-
MLI
2 stops15h 59m
KLM
Deal found 25/5£650
Sun 30/816:30
ORD
-
LHR
Nonstop8h 15m
Multiple Airlines
Tue 8/911:05
LHR
-
ORD
Nonstop9h 05m
Multiple Airlines
Deal found 26/5£652
Sun 19/721:15
ORD
-
LHR
Nonstop8h 00m
British Airways
Tue 25/814:45
LHR
-
ORD
Nonstop8h 50m
British Airways
Deal found 21/5£653
Mon 2/1113:00
MDW
-
LHR
2 stops14h 35m
Virgin Atlantic
Wed 11/1106:30
LHR
-
MDW
2 stops21h 15m
Virgin Atlantic
Deal found 21/5£653
Tue 1/913:30
EVV
-
LHR
2 stops15h 10m
Virgin Atlantic
Wed 30/909:55
LHR
-
EVV
2 stops18h 08m
Virgin Atlantic
Deal found 21/5£653
Thu 10/1217:45
ORD
-
LHR
Nonstop8h 10m
Multiple Airlines
Wed 16/1206:30
LHR
-
ORD
1 stop12h 40m
Multiple Airlines
Deal found 25/5£654
Sun 23/818:45
PIA
-
LHR
1 stop10h 30m
British Airways
Tue 15/906:15
LHR
-
PIA
2 stops22h 48m
British Airways
Deal found 25/5£654

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 26 May 2026.

Round-trip from

£639

One-way from

£237

Popular in

June

Cheapest in

February

Average price

£694

Good round-trip deal

£929 or less

Good one-way deal

£396 or less
Iberia
  • Iberia
  • 17/11-24/11
  • 3 total stops
  • 34h 12m total
  • Illinois to London
Search Deals
British Airways
  • British Airways
  • 15/9
  • 1 total stop
  • 13h 23m total
  • Illinois to London
Search Deals
Highest demand for flights based on searches. 26% potential increase in price (£153 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 6% potential price decrease (£27 potential savings vs. average return price).
Search Deals
Average for round-trip flights in May 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 26 May 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

EvansvilleLondon

EVV - LHR

EVVLHR

Evansville Dress Regional

Tue 1/9

10:05-07:15

1 stop15h 10m

London Heathrow

Tue 29/9

08:40-22:03

2 stops19h 23m

£649

BloomingtonLondon

BMI - LHR

BMILHR

Bloomington-Normal

Sun 23/8

12:09-11:20

1 stop17h 11m

London Heathrow

Tue 15/9

06:30-22:22

2 stops21h 52m

£649

EvansvilleLondon

EVV - LHR

EVVLHR

Evansville Dress Regional

Wed 21/10

17:45-11:20

1 stop11h 35m

London Heathrow

Thu 5/11

06:30-16:54

2 stops16h 24m

£650

MolineLondon

MLI - LHR

MLILHR

Moline Quad-City

Wed 23/9

05:55-06:25

1 stop18h 30m

London Heathrow

Wed 30/9

06:30-16:29

2 stops15h 59m

£650

MolineLondon

MLI - LHR

MLILHR

Moline Quad-City

Wed 23/9

06:00-06:25

1 stop18h 25m

London Heathrow

Wed 30/9

08:40-22:24

2 stops19h 44m

£650

EvansvilleLondon

EVV - LHR

EVVLHR

Evansville Dress Regional

Wed 21/10

10:05-06:20

2 stops14h 15m

London Heathrow

Thu 5/11

08:40-22:03

2 stops19h 23m

£653

ChicagoLondon

MDW - LHR

MDWLHR

Chicago Midway

Wed 21/10

10:35-07:10

2 stops14h 35m

London Heathrow

Fri 30/10

06:20-21:45

2 stops20h 25m

£656

PeoriaLondon

PIA - LHR

PIALHR

Greater Peoria

Sun 23/8

18:45-11:15

1 stop10h 30m

London Heathrow

Tue 15/9

19:25-23:03

2 stops33h 38m

£657

EvansvilleLondon

EVV - LHR

EVVLHR

Evansville Dress Regional

Tue 1/9

13:58-12:50

1 stop16h 52m

London Heathrow

Wed 30/9

13:10-23:21

1 stop16h 11m

£663

EvansvilleLondon

EVV - LHR

EVVLHR

Evansville Dress Regional

Wed 21/10

18:06-11:15

1 stop11h 09m

London Heathrow

Thu 5/11

11:00-23:30

1 stop18h 30m

£663

Flights are sorted by cheapest return flights first.

Deals found on 21/5

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, January is the cheapest month in which you can book a flight from Illinois to London Heathrow Airport (average of £148). Flying from Illinois to London Heathrow Airport in April is currently the most expensive (average of £1,306). 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 26 May 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 26 May 2026.

The most flights from USIL to LHR are scheduled on a Friday (56 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (40 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 90 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 £650, Delta 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 £164. 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 (82%), Austrian Airlines (82%) or United Airlines (82%) 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 £952 for a flight from Illinois to London Heathrow Airport. The cheapest flight overall is £355 while the most popular route, (Chicago O'Hare Intl - London Heathrow) is currently priced at £442.

  • 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, January is the cheapest month in which you can book a flight from Illinois to London Heathrow Airport (average of £148). Flying from Illinois to London Heathrow Airport in April is currently the most expensive (average of £1,306). 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
Croydon
Northampton
Wembley
Luton
Gatwick
Slough
Ilford
Hayes
Brentford
Colchester
Watford
Romford
Kingston upon Thames
Eastbourne
Ipswich
Swindon
Guildford
Southall

Browse thousands of different options on Cheapflights for your next trip

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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 Stansted flights

Top 6 airlines flying from Illinois to Heathrow

Discover the top 6 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 26 May 2026.
AirlineCheapestAverageFlexibilityOn-time
LufthansaCheapest£356Average£512FlexibilityNo cancel feeOn-time76%
Search Lufthansa flights
American AirlinesCheapest£384Average£591FlexibilityNo cancel feeOn-time71%
Search American Airlines flights
British AirwaysCheapest£410Average£581FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Aer LingusCheapest£457Average£625FlexibilityNo cancel feeOn-timeN/A
Search Aer Lingus flights
United AirlinesCheapest£505Average£692FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
IberiaCheapest£516Average£621FlexibilityNo 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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