$428 Find Cheap Flights from Sydney to Illinois - Compare and Save

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 9/7. 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

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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
Chicago3 stops$922
St. Louis
St. Louis1 stop$993
Chicago
Chicago3 stops$922
St. Louis
St. Louis1 stop$993

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

Wed, Sep 9 - Sun, Sep 13
Multiple Airlines Logo
1:15 pm - 10:58 am
SYD
-
MDW
36h 43m
3 stops
Multiple Airlines Logo
7:25 am - 11:50 am
MDW
-
SYD
37h 25m
3 stops
$922Multiple Airlines
Thu, Aug 6 - Fri, Aug 21
American Airlines Logo
9:10 am - 3:54 pm
SYD
-
ORD
21h 44m
1 stop
American Airlines Logo
3:54 pm - 7:05 am
ORD
-
SYD
24h 11m
2 stops
$979American Airlines
Wed, Oct 7 - Wed, Nov 11
American Airlines Logo
1:00 pm - 6:20 pm
SYD
-
STL
21h 20m
1 stop
American Airlines Logo
7:00 am - 9:00 am
STL
-
SYD
33h 00m
1 stop
$993American Airlines
Thu, Sep 3 - Thu, Sep 10
Multiple Airlines Logo
1:15 pm - 5:50 pm
SYD
-
STL
43h 35m
3 stops
Multiple Airlines Logo
10:35 am - 11:50 am
STL
-
SYD
34h 15m
3 stops
$1,010Multiple Airlines
Thu, Aug 6 - Mon, Aug 10
American Airlines Logo
9:10 am - 2:54 pm
SYD
-
ORD
20h 44m
1 stop
American Airlines Logo
9:00 am - 7:05 am
ORD
-
SYD
31h 05m
1 stop
$1,014American Airlines
Mon, Sep 28 - Thu, Oct 1
Qantas Airways Logo
9:10 am - 4:49 pm
SYD
-
ORD
22h 39m
1 stop
Qantas Airways Logo
9:55 am - 7:05 am
ORD
-
SYD
30h 10m
1 stop
$1,031Qantas Airways
Thu, Oct 1 - Tue, Oct 20
Qantas Airways Logo
9:10 am - 3:53 pm
SYD
-
ORD
21h 43m
1 stop
Qantas Airways Logo
1:50 pm - 8:05 am
ORD
-
SYD
26h 15m
1 stop
$1,067Qantas Airways
Wed, Oct 7 - Wed, Nov 11
United Airlines Logo
10:30 am - 4:37 pm
SYD
-
STL
22h 07m
2 stops
United Airlines Logo
1:08 pm - 9:05 am
STL
-
SYD
26h 57m
3 stops
$1,099United Airlines
Mon, Sep 14 - Tue, Oct 6
Delta Logo
9:15 am - 6:19 pm
SYD
-
MDW
24h 04m
2 stops
Delta Logo
1:00 pm - 7:50 am
MDW
-
SYD
26h 50m
2 stops
$1,708Delta
Thu, Sep 10 - Wed, Sep 23
Delta Logo
9:15 am - 6:19 pm
SYD
-
MDW
24h 04m
2 stops
Delta Logo
1:00 pm - 6:50 am
MDW
-
SYD
26h 50m
2 stops
$1,709Delta
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 August.

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 September, when tickets cost $1,056 (return) on average. On the other hand, the most expensive months are July and April, when the average cost of round-trip tickets is $1,362 and $1,332 respectively.

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 18% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 20 weeks before departure.

Good to know

Low season

March

Cheapest flight

$428
Best time to beat the crowds with an average 7% drop in price.
Most popular time to fly with an average 10% 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.

Reviews of the top airlines flying 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 1066 reviews
7.7Boarding
7.4Comfort
8.1Crew
7.2Entertainment
7.0Food
Airline reviews

Great food and good entertainment options for the long flight.

10.0 ExcellentBill, May 2026
SYD - DFW
Read more Qantas Airways reviews

Great food and good entertainment options for the long flight.

We had bulkhead seats in a A380 in the upper deck in seats 31 D and E. Storage was very limited other than in overhead bin - which is not within reach when in seat. Yet paying same price as others in premium economy who have a lot more storage within arm’s reach. Seems very unfair.

Good check in and helpful staff. Delayed for 1 hour. Took about 45 Mins to get baggage’s at DFW . Food was average ( Hindu meal ) . Overall it was good experience

When I originally booked this flight, I was expecting to travel on Qantas. When the itinerary changed and the long-haul segment was operated by American Airlines, we were disappointed but remained open-minded. Unfortunately, the overall service experience fell far short of expectations. This was a long-haul international flight. Getting up periodically to use the restroom or stretch is inevitable, especially on flights of this duration. However, each time we stood up, we felt as though we were inconveniencing the crew. The tone and body language often suggested that we were in the way or disrupting something simply by moving about the cabin. As a result, I avoided getting up as often as I needed to and was physically very sore upon arrival. Meal service was similarly impersonal. The options were presented in single words “beef or veggie,” “pasta or beef” without any description of what was actually being served. There was little engagement or courtesy beyond that. Even simple expressions of gratitude were often not acknowledged. I am accustomed to no-frills travel and do not expect luxury. What was disappointing was not the absence of extras, but the absence of basic warmth and professionalism. On a long-haul international flight, small moments of courtesy and humanity make a significant difference. In this case, the experience felt transactional and dismissive rather than welcoming. I hope this feedback is taken constructively, as there is a meaningful difference between efficient service and indifferent service.

Business seats not as comfortable or private as most competitors (e.g. Qantas was outstanding), and movie selection was much more limited than Qantas or United has been recently

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

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.

Friendly staff, surprisingly good premium economy seats allowing good sleep/ snooze opportunity and very good menu.

The service was excellent. The quarters were a little cramped in Economy, and we had to exist there for 18 hours.

Food was great. Customer Service not so much! Flight Delays.

I almost missed my connection in Chicago due to having to wait on a gate to be open I am assuming. Having to run from E terminal to C terminal and I barely made it there before they closed the door. This may not be the actual airline's fault it's crazy how there is so little time between flight especially when they are placed so far apart in the airport.

The Wi-Fi did not work, so you weren't able to watch entertainment on your own device. They did not have wired headphones so you couldn't watch it on the in-seat entertainment screen either. There was plenty of time to do a drink and snag service but the flight attendants chose not to.

Great experience, boarding was fast and efficient, so much so that we arrived to Chicago very early

The flight did not have its customary snacks during the flight. Apparently they were never loaded on the plane.

The seats on this flight weren’t as comfortable as we had expected. Even leaned back these seats left us feeling crappy in our backs. Also we had to use our own tablets for movies, but nothing in the seats in front of us to hold the tablets up.

Uncomfortable plastic seats even in premium economy. No free wifi. Even paid wifi was spotty to nonexistent. Bad food. Much worse than economy on foreign carriers like Qantas.

It was good but only meal served is very less. Meantime good to add rice and chicken in one of meal

I found the staff to not be very attentive at all. When paying for Business Class you expect a certain type of service and that was not found. They were almost rude even

Great. Food going from Australia to the US was better than other way around, but still needs improvement in terms of quality and quantity!!!

Due to a cancelled flight the day before this flight only had 44 people. Best flight ever on international route. Food getting better. Can United provide fruit ex apples and bananas for snacks? Crew fantastic.

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

Information on your arrival and departure airports