$636 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 7/30. 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$1,017
St. Louis
St. Louis2 stops$1,018
Chicago
Chicago1 stop$1,017
St. Louis
St. Louis2 stops$1,018

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

Thu, Oct 29 - Sun, Nov 1
American Airlines Logo
11:15 am - 6:01 am
SYD
-
ORD
34h 46m
1 stop
American Airlines Logo
10:15 am - 6:10 am
ORD
-
SYD
26h 55m
1 stop
$1,017American Airlines
Mon, Jun 22 - Mon, Aug 17
American Airlines Logo
5:50 pm - 11:57 pm
SYD
-
STL
21h 07m
2 stops
American Airlines Logo
3:32 pm - 7:05 am
STL
-
SYD
24h 33m
2 stops
$1,018American Airlines
Thu, Oct 29 - Sun, Nov 1
American Airlines Logo
11:15 am - 6:01 am
SYD
-
ORD
34h 46m
1 stop
American Airlines Logo
10:15 am - 6:10 am
ORD
-
SYD
26h 55m
1 stop
$1,019American Airlines
Thu, Oct 29 - Sun, Nov 1
American Airlines Logo
11:15 am - 6:01 am
SYD
-
ORD
34h 46m
1 stop
American Airlines Logo
10:15 am - 6:10 am
ORD
-
SYD
26h 55m
1 stop
$1,020American Airlines
Thu, Oct 29 - Sun, Nov 1
American Airlines Logo
11:15 am - 1:27 pm
SYD
-
ORD
42h 12m
1 stop
American Airlines Logo
10:15 am - 6:10 am
ORD
-
SYD
26h 55m
1 stop
$1,022American Airlines
Tue, Jun 23 - Mon, Aug 17
United Airlines Logo
9:30 am - 9:30 pm
SYD
-
STL
27h 00m
2 stops
United Airlines Logo
11:15 am - 7:00 am
STL
-
SYD
28h 45m
2 stops
$1,029United Airlines
Mon, Jun 22 - Sun, Aug 16
United Airlines Logo
9:30 am - 11:57 pm
SYD
-
STL
29h 27m
2 stops
United Airlines Logo
1:36 pm - 7:00 am
STL
-
SYD
26h 24m
2 stops
$1,035United Airlines
Mon, Nov 2 - Wed, Nov 11
Delta Logo
10:40 am - 4:50 pm
SYD
-
MDW
23h 10m
2 stops
Delta Logo
1:05 pm - 8:30 am
MDW
-
SYD
26h 25m
2 stops
$1,041Delta
Mon, Nov 2 - Tue, Nov 10
Delta Logo
10:40 am - 4:49 pm
SYD
-
ORD
23h 09m
2 stops
Delta Logo
3:50 pm - 8:30 am
ORD
-
SYD
23h 40m
2 stops
$1,041Delta
Tue, Jul 14 - Tue, Jul 28
Multiple Airlines Logo
12:00 pm - 6:37 pm
SYD
-
MDW
21h 37m
1 stop
Multiple Airlines Logo
5:46 pm - 11:50 am
MDW
-
SYD
27h 04m
2 stops
$1,614Multiple Airlines
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 October.

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 December, when tickets cost $468 (return) on average. On the other hand, the most expensive months are July and February, when the average cost of round-trip tickets is $920 and $865 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 19% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 6 weeks before departure.

Good to know

Low seasonMarch
Cheapest flight$636
Best time to beat the crowds with an average 6% drop in price.
Most popular time to fly with an average 10% increase in price.
Flight from Sydney to St. Louis

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 1044 reviews
7.5Comfort
8.1Crew
7.7Boarding
7.2Entertainment
7.0Food
Airline reviews

We had a cancellation due to weather, but the American Airlines staff was very helpful. Once we got on a plane, the trip was great.

8.0 ExcellentBill, May 2026
DFW - COS
Read more Qantas Airways reviews

We had a cancellation due to weather, but the American Airlines staff was very helpful. Once we got on a plane, the trip was great.

Great food and good entertainment options for the long flight.

It seems that qantas are trying hard to regain their status as Australia's premier airline. I only flew economy but happy with the service entertainment, food, configuration everything.

Loved the food and beverages available, spacious economy class, excellent entertainment

Very good overall. Highly recommend for all flying to Australia

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.

On the Qantas flight, I could barely hear some of the announcements. It was better when I could read them on the screen.

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

Our boarding and flight was very good. However when we landed and pulled in to the gate it took 55 minutes for the jet bridge to be positioned next to the aircraft. That caused us to miss our ground transportation and it caused us unnecessary last minute transit planning and expense. Our flight was AA1733 on March 17, 2026

We booked with Qantas instead of Delta and we instead flew on American Airlines. American is not our favorite to go on. No leg room and the width of seats are a joke. Your are packed like sardines on American flights.

Boarded early, left early, arrived 40 mins early! A win win for me!

These airplanes should be illegal. The seats are two tight, it is a safety issue. Wheelchair support was ridiculously slow. We almost missed our flight.

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.

This flight is a quick way to get to Chicago, but a bit expensive.

The clerk at check in for my bags was very rude. My credit card was hacked during my vacation and she told me it was not possible to pay in cash for my bag. “You bought the cheapest ticket, you should have bought a ticket that included a bag. If you cannot pay with a credit card, we will not let you on this flight”. She spoke to her supervisor and then told me , I could ask other passengers, if they would use their credit card to check my bag. I had to beg 5 different people, till one agreed to use their credit card. I payed them cash of course. This was a very stressful and humiliating experience for me. I strongly suggest you build in some kind of provision for travelers who got robbed.

O’hsre taxi and deboarding took 40 minutes. Needed 20 minutes extra time between connecting flights to avoid running through terminal.

Flight crew was super friendly and helpful. Food was frequent and honestly pretty good. Plenty of on-board entertainment. Economy seats are super cramped for such a long flight, but the crew allowed people to get up and stretch, and kids could wander with their parents, so we all made it work. Overall a very good experience.

Standard flight with a drinks and a snack- overall very quick flight. The flight attendants were very strict, bordered on rude.

Starlink is great Crew was polite Business class didn’t get a welcome drink just water and snacks were ok

Delayed - weather wasn't bad at either end. Also sat on tarmac in ORD.

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

Information on your arrival and departure airports