Qantas will operate non-stop flights on its new 787-9 Dreamliner aircraft between Perth and London from March 2018.
The 14,498 kilometre service will be the first regular passenger service to directly link Australia with Europe, the airline said.
"This is a game-changing route flown by a game-changing aircraft," Qantas CEO Alan Joyce said in a statement.
"Australians have never had a direct link to Europe before so the opportunities this opens up are huge."
The new flight will operate through Qantas' existing domestic terminals at Perth Airport, which will be upgraded to accommodate international flights.
The airline's current international services from Perth (to Singapore and to Auckland) will also move to this terminal.
Qantas will move its operations to an expanded Terminal 1 at Perth Airport by 2025, pending a commercial agreement.
"We'll be looking at the timing of our domestic flights through Perth to offer the best connections we can to our international flights, particularly given they will all be under the one roof," Mr Joyce said.
Seats on the Perth-London flights will go on sale in April 2017 for the first services from 2018.
The Dreamliner will carry 236 passengers.
Qantas, the West Australian government and Perth Airport will contribute to the upgrade of the airport to facilitate the new route.
The WA government has committed $14 million for capital works to accommodate infrastructure
requirements for Commonwealth border services at domestic terminal T3.
