This might be not the cheapest option from Europe to Australia but if you can reach Zurich you may consider surely one of the best value deals between these continents thanks to service of 4* Swiss Air Lines and 5* Singapore Airlines. Return flights from Zurich to Australia (Brisbane, Perth, Sydney) with one layover in Singapore on the way are available from just €642 incl. taxes, meals, handbag and checked luggage.
You will find limited travel dates when departing from Switzerland to Australia from May to June or late August to the 10th of December 2020. Max stay for 3 months. Book this Swiss/Singapore Airlines promotion by the 18th of March or available until the cheapest tariff has sold out.
Booking sample of Swiss/Singapore Airlines return flights from Zurich to Australia from €642! Outbound from Switzerland to Brisbane on the 11th of May. Inbound from Australia back to Zurich via Singapore on the 25th of May 2020.