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$576+ Cheap flights from Illinois to Australia

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 11/20. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — SYD
Dec 13 — Dec 201
Sat 12/13
Sat 12/20
1 adult, Economy
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Find flight deals from Illinois to Australia

Cheapest flights from Illinois to Australia
Explore the most affordable flight options available from Illinois to Australia. Find the lowest fares from popular airlines and budget airlines, with prices last updated on November 13, 2025.

This BestPriceTravel deal was found by Cheapflights users on 11/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure BestPriceTravel is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/46:17 pmORD - SYD
1 stop21h 43mQantas Airways
Wed 3/47:05 amSYD - ORD
2 stops26h 34mQantas Airways
Deal found 11/13$883
This oojo deal was found by Cheapflights users on 11/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/26:23 pmORD - SYD
1 stop21h 37mQantas Airways
Tue 12/97:05 amSYD - ORD
2 stops27h 47mQantas Airways
Deal found 11/12$950
This oojo deal was found by Cheapflights users on 11/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/48:46 pmORD - MEL
1 stop39h 29mQantas Airways
Thu 12/116:45 amMEL - ORD
2 stops28h 07mQantas Airways
Deal found 11/13$952
This oojo deal was found by Cheapflights users on 11/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/113:11 pmORD - SYD
2 stops36h 39mQantas Airways
Thu 12/1811:20 amSYD - ORD
1 stop21h 13mQantas Airways
Deal found 11/12$972
This oojo deal was found by Cheapflights users on 11/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/48:46 pmORD - MEL
1 stop39h 29mQantas Airways
Wed 1/146:30 pmMEL - ORD
2 stops37h 27mQantas Airways
Deal found 11/12$973
This oojo deal was found by Cheapflights users on 11/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/306:23 pmORD - SYD
1 stop21h 37mQantas Airways
Wed 12/107:05 amSYD - ORD
2 stops25h 57mQantas Airways
Deal found 11/12$980
This Trip.com deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/76:50 amORD - SYD
1 stop33h 10mMultiple Airlines
Fri 12/125:45 pmSYD - ORD
1 stop23h 28mMultiple Airlines
Deal found 11/11$1,001
This Trip.com deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/248:10 amORD - BNE
2 stops34h 10mMultiple Airlines
Thu 11/2711:50 amBNE - ORD
2 stops29h 09mMultiple Airlines
Deal found 11/11$1,002
This oojo deal was found by Cheapflights users on 11/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/18:15 amORD - SYD
1 stop30h 10mQantas Airways
Sun 1/185:50 pmSYD - ORD
2 stops38h 07mQantas Airways
Deal found 11/12$1,009
This lol.travel deal was found by Cheapflights users on 11/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure lol.travel is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/411:45 amORD - SYD
1 stop28h 15mQantas Airways
Mon 3/27:05 amSYD - ORD
2 stops27h 36mQantas Airways
Deal found 11/13$1,022
This Trip.com deal was found by Cheapflights users on 11/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/56:50 amORD - SYD
1 stop31h 35mMultiple Airlines
Tue 12/911:20 amSYD - ORD
2 stops44h 11mMultiple Airlines
Deal found 11/11$1,059
This Kiwi.com deal was found by Cheapflights users on 11/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/66:17 pmORD - SYD
2 stops33h 33mQantas Airways
Thu 3/511:20 amSYD - ORD
1 stop19h 45mQantas Airways
Deal found 11/13$1,061

Cheap flight deals from Illinois to Australia

Keep the following information in mind while searching for Illinois to Australia flight deals. Data was last updated November 13, 2025.

Most accurate provider

Justfly.com
3 stars

Most trusted provider

Justfly.com
3 stars

Round-trip from

$883
(BestPriceTravel)

One-way from

$576
(Trip.com)

Popular in

December

Cheapest in

August

Average price

$965
Provider with most accurate pricing for Chicago (CHI)-Sydney Kingsford Smith flight deals.
Search Deals
Provider most trusted by Cheapflights users for Chicago (CHI)-Sydney Kingsford Smith flights.
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From Illinois to Australia
Search Deals
One-way flight from Illinois to Australia
Search Deals
Highest demand for flights based on searches. 15% potential increase in price ($174 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($37 potential savings vs. average RT price).
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Average for round-trip flights in November 2025
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Illinois to Australia 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 2,558,603 searches. Data last updated November 13, 2025.
Use the filters below to find and compare flights from Illinois to Australia that are best for you.

Fly from

Illinois

Fly to

Australia

Route

Depart

Return

Price

St. LouisMelbourne

STL - AVV

STLAVV

Lambert-St Louis

Mon 2/2

4:05 pm-11:15 pm

3 stops62h 10m

Melbourne Avalon

Sat 2/14

6:00 am-3:29 pm

3 stops50h 29m

$1,153

ChicagoPerth

ORD - PER

ORDPER

Chicago O'Hare Intl

Sun 2/8

1:10 pm-5:50 pm

2 stops38h 40m

Perth

Sun 2/22

8:25 pm-7:35 am

2 stops49h 10m

$1,167

St. LouisMelbourne

STL - MEL

STLMEL

Lambert-St Louis

Fri 2/6

5:04 pm-10:50 pm

2 stops36h 46m

Melbourne

Mon 2/23

11:55 pm-5:05 pm

2 stops34h 10m

$1,182

St. LouisMelbourne

STL - AVV

STLAVV

Lambert-St Louis

Fri 2/6

4:05 pm-11:15 pm

3 stops62h 10m

Melbourne Avalon

Mon 2/23

6:00 am-3:29 pm

3 stops50h 29m

$1,196

St. LouisMelbourne

STL - MEL

STLMEL

Lambert-St Louis

Mon 12/8

5:30 pm-8:20 am

2 stops45h 50m

Melbourne

Mon 12/15

12:00 pm-11:57 pm

1 stop28h 57m

$1,214

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Thu 12/11

1:16 pm-9:00 am

2 stops26h 44m

Sydney Kingsford Smith

Thu 12/18

5:45 pm-9:25 pm

2 stops44h 40m

$1,225

ChicagoSydney

MDW - SYD

MDWSYD

Chicago Midway

Sun 2/1

6:20 am-7:25 am

2 stops32h 05m

Sydney Kingsford Smith

Thu 2/12

11:20 am-11:25 pm

2 stops29h 05m

$1,235

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Fri 11/28

7:00 am-9:50 am

2 stops33h 50m

Sydney Kingsford Smith

Sun 12/14

2:05 pm-7:27 pm

1 stop22h 22m

$1,236

ChicagoSydney

ORD - SYD

ORDSYD

Chicago O'Hare Intl

Tue 2/3

6:40 pm-6:25 pm

2 stops30h 45m

Sydney Kingsford Smith

Wed 2/11

9:00 am-4:49 pm

2 stops24h 49m

$1,237

ChicagoBrisbane

ORD - BNE

ORDBNE

Chicago O'Hare Intl

Wed 2/11

6:40 pm-5:10 pm

2 stops30h 30m

Brisbane

Sun 3/1

6:30 pm-5:41 pm

2 stops39h 11m

$1,249

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/13

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

Have a flexible travel schedule? Discover the best time to fly to Australia from Illinois with our price prediction graph.
Estimated round-trip 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 Australia

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

Currently, August is the cheapest month in which you can book a flight from Illinois to Australia (average of $198). Flying from Illinois to Australia in October is currently the most expensive (average of $832). 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 AU?

Find hourly flight availability from Illinois to Australia. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated November 13, 2025.

It’s optimal to fly from Illinois to Australia at noon. By choosing this option you can save up to 16% on the cost of your flight, compared to a flight in the evening.

What is the cheapest day to fly from Illinois to Australia?

Use this chart to determine the cheapest time to fly round-trip from Illinois to Australia. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Illinois to Australia flight should consider departing on Friday mornings when fares are most often at their lowest. Thursday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

Related info for your journey

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

    Departing from Illinois to Australia will take you 22h 09m. Illinois and Australia are separated by a distance of 9479 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

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

    $682 is the cheapest one-way deal found within the past few days, from Qantas Airways. You may also be able to find cheap deals on United Airlines and Delta, with prices starting from $700 and $762, respectively.

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

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

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

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

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

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

    Currently, August is the cheapest month in which you can book a flight from Illinois to Australia (average of $198). Flying from Illinois to Australia in October is currently the most expensive (average of $832). 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

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Top 10 airlines flying from Illinois to Australia

Discover the top 10 airlines that operate flights from Illinois to Australia. 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 2,558,603 searches. Data last updated November 13, 2025.
AirlineCheapestAverageFlexibilityOn-time
Qantas AirwaysCheapest$673Average$1,338FlexibilityNo cancel feeOn-time74%
ANACheapest$679Average$1,193FlexibilityNo cancel feeOn-time80%
American AirlinesCheapest$679Average$1,256FlexibilityNo cancel feeOn-time71%
Fiji AirwaysCheapest$772Average$1,422FlexibilityNo cancel feeOn-time74%
DeltaCheapest$846Average$1,018FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$870Average$1,500FlexibilityNo cancel feeOn-time69%
Air CanadaCheapest$872Average$1,270FlexibilityNo cancel feeOn-time67%
Qatar AirwaysCheapest$1,229Average$1,331FlexibilityNo cancel feeOn-time68%
Air New ZealandCheapest$1,264Average$1,531FlexibilityNo cancel feeOn-time78%
Cathay PacificCheapest$1,470Average$2,048FlexibilityNo cancel feeOn-time72%

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