Cheap flights from Chicago to Sydney (ORD to SYD) from $1,719

The cheapest month to fly is November, and departing on Thursdays typically offers the best fares. Book 6–8 weeks ahead for the best prices.

Book at the right time: For international flights, aim to book 6–10 weeks ahead. Last-minute fares on Chicago to Sydney are rarely cheap, and prices spike sharply within 2 weeks of departure.

Shift your dates by a day or two: Thursdays are typically the cheapest day to fly this route. Avoiding Friday and Sunday departures can save significantly. November is historically the cheapest month on this route.

Weigh up connecting flights: Connecting flights on Chicago to Sydney can be 20–40% cheaper than direct options. If you have time to spare, it's worth comparing.

Factor in baggage fees: Low-cost carriers on this route often advertise attractive base fares but charge separately for checked luggage. Always compare the all-in price — a $20 cheaper fare plus $50 baggage fee is no saving. SWISS and Delta Air Lines may have different inclusions, so check each airline's fare conditions.

Search in private browsing: Some booking sites use cookies to track repeat searches and may show higher prices after multiple lookups. Use an incognito or private window — or just use Booked AI, which pulls live prices without any tracking markup.

Compare two one-ways against a return: On some international routes, booking a one-way with one airline and the return with another can undercut a standard return ticket — especially if a budget carrier covers one direction. Check both options with the flexible dates calendar above.

The cheapest flights from Chicago to Sydney start from $1,719, with typical prices ranging from $1,719 to $2,019.

The typical flight time from Chicago to Sydney is approximately 21 hours and 55 minutes.

Airlines operating this route include SWISS, Delta Air Lines, United Airlines, Singapore Airlines, Qantas, Cathay Pacific, Lufthansa, JAL, Air New Zealand, ANA, British Airways, Etihad Airways, Korean Air, Air Canada, Qatar Airways, American Airlines, Air Tahiti Nui, Alaska Airlines, Asiana Airlines.