Air Canada will relaunch its London to Ottawa service next summer, offering four flights a week from 31 March.
The summer-only service from Heathrow will be operated by a Boeing 787 aircraft with three cabins.
Flights will depart on Mondays, Wednesdays, Thursdays and Saturdays.
The airline said it will consider upgrading the service between the two capital cities to a year-round connection with more frequencies once the long-range A321XLR aircraft it has on order start to arrive towards the end of next year.
Currently, the London to Ottawa service is due to end on 25 October 2025.