Three-times-weekly flights to the Cornish holiday hot spot will get under way from 8 June.
The programme will run through to the end of October.
EasyJet will operate the flights on Tuesdays, Thursdays and Saturdays.
Return fares lead in from £53.98.
Ali Gayward, easyJet’s UK country manager, said she was confident the route would be popular.
"This is an exciting route for customers wishing to visit Cornwall for a much-needed break and to reconnect with friends and family," said Gayward.
She added it would "equally benefit" those in Cornwall, offering a "convenient link" to the capital.
Pete Downes, managing director of Newquay airport, added: "I’m certain that this new route will be welcomed by Cornish residents who have long told us they want more great-value flights to London.
"It will also provide a fast and convenient travel option for those in London and the south-east dreaming of a domestic break in Cornwall this summer."
