$571 Find Cheap Flights from Sydney to Illinois

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Sydney to Illinois departing on 3/5. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

KAYAK searches hundreds of travel sites at once for deals on flights to Illinois

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Sydney to Illinois, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Sydney to Illinois, as well as popular online travel agencies
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Cheap Flights from Sydney to Illinois

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
Chicago
Chicago1 stop$1,010
St. Louis
St. Louis2 stops$919
Chicago
Chicago1 stop$1,010
St. Louis
St. Louis2 stops$919

Book Cheap Sydney to Illinois Plane Tickets

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Sydney to Illinois that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Sydney to Illinois

Sat, Feb 14 - Wed, Feb 18
Air Canada Logo
11:20 am - 3:29 pmSYD-STL
45h 09m2 stops
Air Canada Logo
2:45 pm - 9:35 amSTL-SYD
25h 50m2 stops
$919Air Canada
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Sat, Feb 14 - Wed, Feb 18
Air Canada Logo
11:20 am - 3:29 pmSYD-STL
45h 09m2 stops
Air Canada Logo
2:45 pm - 9:35 amSTL-SYD
25h 50m2 stops
$920Air Canada
Find Deal
Sat, May 16 - Sat, Jun 6
American Airlines Logo
9:10 am - 5:24 pmSYD-ORD
23h 14m1 stop
American Airlines Logo
10:17 pm - 7:05 amORD-SYD
41h 48m1 stop
$1,016American Airlines
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Fri, May 1 - Wed, May 13
American Airlines Logo
9:10 am - 5:34 pmSYD-ORD
23h 24m2 stops
American Airlines Logo
3:17 pm - 7:05 amORD-SYD
24h 48m1 stop
$1,017American Airlines
Find Deal
Wed, Jan 14 - Wed, Jan 21
Qantas Airways Logo
2:05 pm - 4:14 pmSYD-STL
19h 09m1 stop
Qantas Airways Logo
11:55 am - 6:55 amSTL-SYD
26h 00m1 stop
$1,169Qantas Airways
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Tue, Jan 13 - Tue, Jan 20
Delta Logo
10:40 am - 4:29 pmSYD-MDW
22h 49m2 stops
Delta Logo
9:50 am - 6:50 amMDW-SYD
28h 00m2 stops
$1,185Delta
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Wed, Jan 14 - Wed, Jan 21
United Airlines Logo
12:10 pm - 4:55 pmSYD-STL
21h 45m2 stops
United Airlines Logo
9:57 am - 7:00 amSTL-SYD
28h 03m2 stops
$1,188United Airlines
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Thu, Jan 15 - Thu, Jan 29
United Airlines Logo
11:50 am - 3:52 pmSYD-STL
21h 02m1 stop
United Airlines Logo
10:07 am - 9:15 amSTL-SYD
30h 08m2 stops
$1,213United Airlines
Find Deal
Thu, Jan 15 - Thu, Jan 29
Qantas Airways Logo
2:05 pm - 4:14 pmSYD-STL
19h 09m1 stop
Qantas Airways Logo
7:04 am - 7:25 amSTL-SYD
31h 21m1 stop
$1,241Qantas Airways
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Wed, Apr 29 - Wed, May 13
Delta Logo
9:25 am - 9:45 pmSYD-MDW
27h 20m2 stops
Delta Logo
2:00 pm - 6:35 amMDW-SYD
25h 35m2 stops
$1,354Delta
Find Deal
Booking Insights

KAYAK's insights & trends for Sydney to Illinois flights

Get data-powered insights and trends into flights from Sydney to Illinois to help you find the cheapest flights, the best time to fly and much more.

How much is a round-trip flight from Sydney to Illinois?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Sydney to Illinois departing in April.

What is the cheapest month to fly from Sydney to Illinois?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Sydney to Illinois, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Sydney to Illinois is March, when tickets cost $735 (return) on average. On the other hand, the most expensive months are December and January, when the average cost of round-trip tickets is $1,487 and $1,275 respectively.

What’s the cheapest day of the week to fly from Sydney to Illinois?

The average price of all round-trip flights from Sydney to Illinois clicked on KAYAK for each day over the last 12 months.

Your flight ticket price will generally be cheaper if you fly to Illinois on a Monday and more expensive on a Sunday. On your return trip to Sydney, you should consider flying back on a Saturday, and avoid Thursdays for better deals.

How far in advance should I book a flight from Sydney to Illinois?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Sydney to Illinois, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Sydney to Illinois, you should book around 2 weeks before departure, which saves you about 22% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 21 weeks before departure.

Good to know

Low seasonFebruary
Cheapest flight$571
Best time to beat the crowds with an average 3% drop in price.
Most popular time to fly with an average 7% increase in price.
Flight from Sydney to Chicago O'Hare Airport

FAQs - booking Illinois flights

  • How does KAYAK find such low prices on flights from Sydney to Illinois?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Sydney to Illinois.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Sydney to Illinois?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from Sydney to Illinois is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Sydney to Illinois?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly from Sydney to Illinois with an airline and back with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Sydney to Illinois?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying from Sydney to Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • What is the cheapest time of day to fly to Illinois?

    The cheapest time of day to fly to Illinois is generally at night, when round-trip flights cost $1,141 on average. Morning departures are around 1% more expensive than evening flights, on average. The most expensive time of day to fly to Illinois is generally in the morning, which is peak travel time and where the average cost of a ticket is $1,365.

Reviews of the top 3 airlines serving from Sydney to Illinois

 
See real verified KAYAK customer reviews for airlines flying from Sydney to Illinois. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Sydney to Illinois? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.5
Qantas AirwaysOverall score based on 946 reviews
7.7Boarding
7.5Comfort
7.0Food
8.1Crew
7.2Entertainment
Airline reviews

Basic airline, aircraft and service. AA gets you from point A to B. My flight was delayed by 2 hours too.

6.0 GoodSandipan, Oct 2025SYD - DFW
Read more Qantas Airways reviews

Basic airline, aircraft and service. AA gets you from point A to B. My flight was delayed by 2 hours too.

No internet on flight, which makes log travels really hard.

My flight from Dallas to Sydney was cancelled. My entire trip was rerouted to include the following: Hartford to Washington DC Washington DC to JFK JFK to Auckland Auckland to Christchurch I paid for an aisle seat on the flight to Auckland and was asked if I would take a window seat to accommodate a family. The agent at the podium failed to mention that the family had a 3 month old baby and that a bassinet would be used during the 16 hour flight. The only way I could get out of my seat was to crawl under the bassinet of the sleeping baby. I think it is wrong that I was no given the choice to sit in another seat, that the agent knew what she was doing and chose to not properly disclose my seating arrangement. Terrible treatment.

they ran out of fruit for breakfast and so I just had a yogurt instead. other than that the flight was good

by the time they got to our row, they were out of some of the food options. games and movies were great but maybe more game options like tetris or pac man would be great

Great as usual, some delays but well communicated and made up for in the air

Poor! This flight was delayed 14 hours. There was no assistance in helping customers find other routes to their destination, nor any other kind of support. It was a chaotic experience. I'm not likely to fly with AA going forward.

Business class points redemption - good value for points paid, dubious value if out of your own pocket, domestic class business product okay for this length of flight. The flight left and arrived on time, crew were good, aircraft was a bit old and tired, but still miles ahead of their competitors in Virgin and Jetstar.

We were upgraded and after just a short delay in attending to a safety check we were on our way. Would definately fly Qantas International on their Dreamliner again.

I tried to check in online but was unable to do so. I stood in line for nearly two hours to check in. American Airlines was understaffed. When I finally got to the kiosk to check in, I was still unable to check in. No AA staff was available to help. Finally one of the airport security agents who was helping passengers became of lack of AA Staff told me: “I think the reason you can’t check in is that you are starting your name with an upper case letter when you write it. Just write it with all lower case letters.” That did allow me to check in. HOW COULD ANYONE POSSIBLY KNOW THAT IF THEY USE AN INITIAL UPPER CASE LETTER TO SPELL THEIR OWN NAME, AA WOULD NOT ALLOW THEM TO CHECK IN?????? Then I had to wait in line over half an hour again to drop off my baggage. Although I arrived at the airport 3 hours early, by the time I got to the gate, they had already started boarding.

Door to door, the crew and staff were amazing. It was a stressful travel day with delays, but they were focused on customers and doing what they could to get us to our destinations.

United has come a long way, it’s been a fantastic experience traveling with them.

This flight leg was fantastic - super comfortable and a great selection of things to watch on the TV. Staff were excellent, really above and beyond.

Flight was delayed only slightly before takeoff due to traffic control. However, the flight arrived early to ORD. Good flight. United has been very reliable for me.

Another delayed flight. When the delays exceed the duration of the flight, it’s a problem.

After boarding the plane in Chicago, the passengers were told that there was a technical problem with the plane. Passengers remained on the plane as they tried to fix the problem. After what was probably an hour passengers were told that there was a need to change planes as the problem was not solved. Passengers disembarked and boarded another plane. After taxing to the runway and waiting for takeoff, passengers were told that owing to the thunderstorm the flight was unable to take off but would try and reroute. After some time passengers were told there wasn't enough fuel for the new route and the plane had to return to the gate for additional fuel. after another log delay the flight got underway. On the plane there was food, drinks, ice or entertainment. We were a glass of water, which appeared rationed. Flight arrived about 5 hours late. The pilot was fantastic and communicated with the passengers throughout the ordeal.

Excellent all round, first time flying United. App is very helpful.

Efficient all round, very good crew. Short flight so the food, of course, was just snacks

Better WiFi. I cannot understand that in 2025, United is so behind on a technology that is now a necessity and still painfully unreliable, slow and keeps disconnecting.

Trip was great. A wild landing in Ottawa with the wind and rain, but the pilot did a great job. Always love flying United.👍

I enjoyed the extra leg room compared to other airlines. The first stewards made my daughter’s birthday special by giving her an extra snack. Then the last one coming home from Chicago to Appleton made our night really enjoyable Thanks for making our trip enjoyable

It was good..clean, comfy seat. Friendly warm welcoming crew. Was able to check my cabin luggage at the gate which I was able to pickup in a decent time from baggage claim. The app gave all updates from delays to baggage claim info. Overall smooth flight.

It was a typical flight. We had a delay which seems to be the normality now. And we had no in flight service due to conditions.

After we landed we sat on the tarmac for 1.5 hours waiting to get to our gate. Ridiculous.

Flight, food and crew were all good, friendly and very satisfactory.

Terrible. Flight delayed for more than 8 hours with only a $12 meal voucher provided for the inconvenience. The airplane did not have breaks on arrival yet they still made us go through the motions and board on time knowing we could not take off then sit for 40+ minutes before having to get of the time. A complete waste of my time. I cannot believe they can stay business with these shenanigans. I’ll avoid this company like the plague moving forward as the lack of accountability is disgraceful.

This was the best 2 flights I have had with American out of SGF. Great crew both flights.

Premium economy seat was decent. As always poor headphones, poor food and beverage, crew is not overly friendly

Excellent - explanations were clear staff was nice and flight was comfortable

Lost bag and 2 days no word leaving for cruise no clothes or stuff

Everything you need to know for your flight from Sydney to Illinois

Information on your arrival and departure airports