Australia's national carrier says it will connect Perth, in the west of the country, to the UK capital using Boeing 787-9 Dreamliners.
The 9,000 mile (14,498km) flight will take 17 hours.
Perth will be a hub for passengers from eastern Australia going to the UK, tourism minister Steven Ciobo said.
He also said the new service would boost employment and tourism in Australia, a sector growing three times faster than the rest of the national economy, and one that supports 580,000 jobs.
