Cheap flights from Illinois to Sydney from $799

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 9/11. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — SYD
18 Oct — 25 Oct1
1 adult
1 adult, Economy

Cheap flight deals from Illinois to Sydney

Keep the following information in mind while searching for Illinois to Sydney flight deals. Data was last updated 18 September 2025.

Round-trip from

$1,511

One-way from

$799

Popular in

December

Cheapest in

August

Average price

$1,497
Qantas Airways
  • Qantas Airways
  • 5/11-23/11
  • 3 total stops
  • 75h 58m total
  • Illinois to Sydney
9/11
  • 9/11
  • 3 total stops
  • 58h 50m total
  • Illinois to Sydney
Highest demand for flights based on searches. 15% potential increase in price ($412 potential increase over avg. return price).
Cheapest flight prices on average. 3% potential price decrease ($84 potential savings vs. average return price).
Average for round-trip flights in September 2025

Find flight deals from Illinois to Sydney

Cheapest flights from Illinois to Sydney
Explore the most affordable flight options available from Illinois to Sydney. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 18 September 2025.

Wed 5/1107:00STL - SYD
2 stops33h 50mQantas Airways
Sun 23/1114:05SYD - STL
1 stop19h 27mQantas Airways
Deal found 16/9$1,655
Mon 29/906:00PIA - SYD
2 stops34h 00mUnited Airlines
Sat 4/1010:20SYD - PIA
2 stops26h 07mUnited Airlines
Deal found 16/9$1,697
Tue 11/1117:58STL - SYD
2 stops25h 32mFiji Airways
Tue 25/1114:10SYD - STL
2 stops22h 20mFiji Airways
Deal found 17/9$1,716
Wed 29/1006:39STL - SYD
1 stop34h 21mQantas Airways
Thu 13/1117:50SYD - STL
2 stops42h 40mQantas Airways
Deal found 17/9$1,760
Wed 29/1006:39STL - SYD
1 stop34h 21mQantas Airways
Sat 15/1119:15SYD - STL
2 stops38h 53mQantas Airways
Deal found 16/9$1,761
Wed 22/1006:00ORD - SYD
2 stops33h 30mMultiple Airlines
Fri 24/1018:45SYD - ORD
1 stop21h 14mMultiple Airlines
Deal found 17/9$1,764
Sat 1/1106:30ORD - SYD
2 stops47h 20mMultiple Airlines
Sat 8/1106:00SYD - ORD
2 stops34h 00mMultiple Airlines
Deal found 17/9$1,773
Fri 31/1010:00ORD - SYD
2 stops28h 10mMultiple Airlines
Fri 7/1117:45SYD - ORD
1 stop22h 15mMultiple Airlines
Deal found 16/9$1,791
Sat 29/1116:25ORD - SYD
1 stop34h 50mANA
Tue 10/221:45SYD - ORD
1 stop26h 35mANA
Deal found 17/9$1,793
Mon 27/1016:44ORD - SYD
3 stops28h 01mMultiple Airlines
Sun 9/1114:00SYD - ORD
3 stops33h 25mMultiple Airlines
Deal found 16/9$1,802
Tue 28/1010:00ORD - SYD
2 stops28h 10mMultiple Airlines
Sat 8/1117:45SYD - ORD
1 stop22h 15mMultiple Airlines
Deal found 16/9$1,806
Wed 12/1110:00ORD - SYD
2 stops28h 25mMultiple Airlines
Mon 17/1117:45SYD - ORD
1 stop22h 15mMultiple Airlines
Deal found 18/9$1,812

Cheapflights Fare Finder

 
Customise your flight search to find flights from Illinois to Sydney 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 647,157 searches. Data last updated 18 September 2025.
Use the filters below to find and compare flights from Illinois to Sydney that are best for you.

Fly from

Illinois

Fly to

Sydney

Route

Depart

Return

Price

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Wed 5/11

15:59-07:35

2 stops46h 36m

Sydney Kingsford Smith

Sun 23/11

11:20-23:42

1 stop29h 22m

$1,511

PeoriaSydney

PIA - SYD

PIASYD

Greater Peoria

Mon 29/9

06:00-07:00

2 stops34h 00m

Sydney Kingsford Smith

Sat 4/10

10:20-21:27

2 stops26h 07m

$1,697

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Wed 29/10

06:39-09:00

1 stop34h 21m

Sydney Kingsford Smith

Sat 15/11

19:15-17:08

2 stops38h 53m

$1,761

ChicagoSydney

ORD - SYD

ORDSYD

Chicago O'Hare Intl

Wed 12/11

10:00-07:25

2 stops28h 25m

Sydney Kingsford Smith

Mon 17/11

17:45-23:00

1 stop22h 15m

$1,812

PeoriaSydney

PIA - SYD

PIASYD

Greater Peoria

Fri 31/10

17:18-09:05

2 stops23h 47m

Sydney Kingsford Smith

Fri 7/11

11:50-20:56

2 stops26h 06m

$1,851

PeoriaSydney

PIA - SYD

PIASYD

Greater Peoria

Sun 2/11

15:30-09:05

2 stops24h 35m

Sydney Kingsford Smith

Sun 9/11

12:10-10:16

2 stops39h 06m

$1,853

PeoriaSydney

PIA - SYD

PIASYD

Greater Peoria

Tue 16/12

13:15-09:15

2 stops27h 00m

Sydney Kingsford Smith

Thu 8/1

11:20-10:10

2 stops39h 50m

$1,877

ChicagoSydney

ORD - SYD

ORDSYD

Chicago O'Hare Intl

Tue 28/10

18:16-12:45

2 stops26h 29m

Sydney Kingsford Smith

Tue 11/11

14:10-19:40

2 stops22h 30m

$1,878

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Wed 29/10

06:39-12:45

2 stops38h 06m

Sydney Kingsford Smith

Thu 13/11

14:00-22:29

2 stops25h 29m

$1,902

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Wed 5/11

16:35-07:00

1 stop21h 25m

Sydney Kingsford Smith

Sun 23/11

11:50-18:47

1 stop23h 57m

$1,938

Flights are sorted by cheapest return flights first.

Deals found on 17/9

Showing 1-10 of 60 results
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Best time to book a flight from Illinois to Sydney

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

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

Currently, May is the cheapest month in which you can book a flight from Illinois to Sydney (average of $129). Flying from Illinois to Sydney in October is currently the most expensive (average of $171). 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 SYD?

Find hourly flight availability from Illinois to Sydney. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 18 September 2025.

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

How much does it cost for a return flight from Illinois to Sydney?

Related info for your journey

Find useful and relevant information for your journey from Illinois to Sydney. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
  • What airport do you fly into for flights to Sydney from Illinois?

    Located just 7.5 km from the city centre, Sydney Kingsford Smith (SYD) is the airport most travelers will use when flying to Sydney from Illinois.

  • How long is the flight from Illinois to Sydney?

    A quick flight from Illinois to Sydney can take about 25h 01m. Qantas Airways provides one of the quickest options available for as low as $1,946. The distance between Illinois and Sydney is about 14571 km. Both multi-stop and direct flights can be found to your destination and back.

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

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Illinois to Sydney 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 Sydney?

    Currently, May is the cheapest month in which you can book a flight from Illinois to Sydney (average of $129). Flying from Illinois to Sydney in October is currently the most expensive (average of $171). 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 Sydney?

Book flights to Sydney if you plan to visit one of these locations
Parramatta
Wollongong
Katoomba
Penrith
Manly
Terrigal
Lithgow
Randwick
Bondi Beach
Coogee
Cronulla
Leura

Browse thousands of different options on Cheapflights for your next trip

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Top 2 airlines flying from Illinois to Sydney

Discover the top 2 airlines that operate flights from Illinois to Sydney. 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 647,157 searches. Data last updated 18 September 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$1,246Average$1,762FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
Qantas AirwaysCheapest$1,310Average$1,408FlexibilityNo cancel feeOn-time74%
Search Qantas Airways flights

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

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