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Cheap flights from St. Louis to Sydney from $729

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 25/2. Fares are subject to change and may not be available on all flights or dates of travel.
STL — SYD
16 Mar — 23 Mar1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from St. Louis to Sydney

Enter your travel dates to find the best prices.

Cheapest flights from St. Louis to Sydney
Explore the most affordable flight options available from St. Louis to Sydney. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 14 February 2026.

Thu 19/316:13
STL
-
SYD
2 stops36h 37m
Qantas Airways
Wed 25/311:20
SYD
-
STL
1 stop28h 38m
Qantas Airways
Deal found 11/2$1,270
Thu 12/206:38
STL
-
SYD
1 stop33h 22m
Qantas Airways
Thu 19/217:50
SYD
-
STL
2 stops40h 23m
Qantas Airways
Deal found 11/2$1,283
Tue 17/206:38
STL
-
SYD
1 stop33h 22m
Qantas Airways
Thu 19/214:35
SYD
-
STL
2 stops43h 38m
Qantas Airways
Deal found 13/2$1,287
Tue 3/306:38
STL
-
SYD
2 stops55h 57m
Qantas Airways
Tue 10/311:20
SYD
-
STL
1 stop28h 38m
Qantas Airways
Deal found 13/2$1,500
Thu 26/206:38
STL
-
SYD
2 stops45h 12m
Qantas Airways
Mon 2/317:45
SYD
-
STL
1 stop23h 14m
Qantas Airways
Deal found 10/2$1,506
Sun 20/905:20
STL
-
SYD
2 stops35h 00m
Air Canada
Sun 4/1010:20
SYD
-
STL
2 stops25h 40m
Air Canada
Deal found 10/2$1,625
Sat 1/812:10
STL
-
SYD
2 stops52h 10m
Air Canada
Sun 9/809:20
SYD
-
STL
2 stops48h 07m
Air Canada
Deal found 12/2$1,628
Mon 7/912:10
STL
-
SYD
2 stops28h 10m
Air Canada
Mon 14/909:20
SYD
-
STL
2 stops48h 21m
Air Canada
Deal found 13/2$1,629
Sun 24/516:50
STL
-
SYD
2 stops23h 30m
Air Canada
Tue 2/609:20
SYD
-
STL
2 stops29h 38m
Air Canada
Deal found 11/2$1,639
Wed 20/507:30
STL
-
SYD
2 stops32h 50m
Air Canada
Wed 27/509:20
SYD
-
STL
2 stops41h 46m
Air Canada
Deal found 11/2$1,642
Sat 28/316:05
STL
-
SYD
2 stops48h 15m
Air Canada
Tue 7/409:20
SYD
-
STL
2 stops26h 34m
Air Canada
Deal found 14/2$1,646

Find flight deals from St. Louis to Sydney

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Sydney (SYD). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated 14 February 2026.

Round-trip from

$1,270

One-way from

$729

Popular in

December

Cheapest in

August

Average price

$1,904
Qantas Airways
  • Qantas Airways
  • 19/3-25/3
  • 3 total stops
  • 65h 15m total
  • St. Louis to Sydney
Search Deals
25/2
  • 25/2
  • 3 total stops
  • 50h 44m total
  • St. Louis to Sydney
Search Deals
Highest demand for flights based on searches. 4% potential increase in price ($145 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($45 potential savings vs. average return price).
Search Deals
Average for round-trip flights in February 2026
Search Deals

Cheapflights Fare Finder

 
Customise your flight search to find flights from St. Louis 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 14 February 2026.
Use the filters below to find and compare flights from St. Louis to Sydney that are best for you.

Fly from

St. Louis

Fly to

Sydney

Route

Depart

Return

Price

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Tue 3/3

06:38-07:35

2 stops55h 57m

Sydney Kingsford Smith

Tue 10/3

11:20-23:58

1 stop28h 38m

$1,500

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Thu 26/2

06:38-20:50

2 stops45h 12m

Sydney Kingsford Smith

Mon 2/3

17:45-23:59

1 stop23h 14m

$1,506

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Sat 1/8

12:10-07:20

2 stops52h 10m

Sydney Kingsford Smith

Sun 9/8

09:20-18:27

2 stops48h 07m

$1,629

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Mon 18/5

07:30-07:20

2 stops32h 50m

Sydney Kingsford Smith

Fri 22/5

09:20-12:06

2 stops41h 46m

$1,701

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Wed 4/3

16:05-09:35

2 stops48h 30m

Sydney Kingsford Smith

Tue 10/3

10:20-15:29

2 stops45h 09m

$1,702

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Wed 20/5

13:00-07:20

3 stops51h 20m

Sydney Kingsford Smith

Wed 27/5

09:20-20:05

3 stops49h 45m

$1,711

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Sat 7/3

18:18-14:50

2 stops27h 32m

Sydney Kingsford Smith

Sat 14/3

11:20-23:58

1 stop28h 38m

$1,719

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Mon 4/5

06:00-08:45

2 stops35h 45m

Sydney Kingsford Smith

Mon 18/5

11:55-22:30

2 stops25h 35m

$1,742

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Mon 18/5

15:38-07:30

2 stops24h 52m

Sydney Kingsford Smith

Fri 22/5

17:50-23:56

1 stop21h 06m

$1,743

St. LouisSydney

STL - SYD

STLSYD

Lambert-St Louis

Sat 23/5

13:00-07:20

2 stops51h 20m

Sydney Kingsford Smith

Tue 2/6

09:20-12:06

2 stops41h 46m

$1,755

Flights are sorted by cheapest return flights first.

Deals found on 11/2

Showing 1-10 of 18 results
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Best time to book a flight from St. Louis to Sydney

Have a flexible travel schedule? Discover the best time to fly to Sydney from St. Louis 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 St. Louis to Sydney

What is the cheapest month to book a flight from St. Louis to Sydney?

Currently, August is the cheapest month in which you can book a flight from St. Louis to Sydney (average of $923). Flying from St. Louis to Sydney in June is currently the most expensive (average of $1,772). 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.

How much does it cost for a return flight from St. Louis to Sydney?

Related info for your journey

Find useful and relevant information for your journey from St. Louis to Sydney. 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 St. Louis to Sydney?

    A quick flight from St. Louis to Sydney can take about 52h 10m. Qantas Airways provides one of the quickest options available for as low as $1,629. There are 14571 km between St. Louis and Sydney. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

  • Can I find deals for flights from St. Louis to Sydney that include hotel bookings?

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

  • How can I find direct flights from St. Louis to Sydney?

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

  • Can I find deals for business class flights from St. Louis to Sydney?

    Yes. Cheapflights offers flight deals from St. Louis 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 St. Louis to Sydney?

    Currently, August is the cheapest month in which you can book a flight from St. Louis to Sydney (average of $923). Flying from St. Louis to Sydney in June is currently the most expensive (average of $1,772). 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
Penrith
Manly
Katoomba
Terrigal
Lithgow
Leura
Coogee
Cronulla
Randwick
Bondi Beach

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for St. Louis to Sydney

See prices for flight routes from nearby airports that may be better suited for you.
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Fly with Cheapflights

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How does Cheapflights help users find flights from St. Louis to Sydney?

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Why should you use Cheapflights to find cheap flight tickets from St. Louis to Sydney?

By finding flights from multiple airlines and providers at completely no cost, Cheapflights helps millions of users like you annually find the best flights to Sydney from St. Louis.

Can Cheapflights find flights from St. Louis to Sydney with no change fees?

Need flexible booking options for your flight to Sydney from St. Louis? Don’t worry, Cheapflights have you covered. Use our search filter to only show flights with no change fees.

Can Cheapflights notify me if prices for flights from St. Louis to Sydney become cheaper?

Yes! Start tracking prices for St. Louis to Sydney flights today and get alerted whenever prices for these flights change. To access this feature, click the bell icon next to the flight deals above, which will prompt you for a valid email address to receive your alerts.

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