The States subsidised route to Terminal 5 begins on Sunday (19 April) with treats for passengers and a water salute expected.
The new route into west London from Guernsey was announced in late November '25.
BA is being subsidised by the States to run a daily lunchtime service, arriving just before 1pm and returning an hour later.
The idea is to open up a different London or world gateway to islanders, with access to multiple international carriers from Heathrow.
It is also designed to encourage business people, families and tourists to use it as an alternative London route to Guernsey.
It is being actively promoted by Visit Guernsey, BA and Heathrow Airport.
The airline will use either an Airbus A319 or an A320 NEO, although runway length in Guernsey will likely cap passenger numbers below capacity.
Traditionally, a new aircraft or route is welcomed by a water arch performed by the airport fire trucks.
Speaking late last year, when the route was announced, British Airways’ Chief Planning and Strategy Officer, Neil Chernoff, says Guernsey will expand the airline's Heathrow based short-haul network to around 100 destinations:
“The addition of Guernsey is something we know our customers have been eagerly awaiting.
"As the only direct service between Heathrow and Guernsey, the route will offer conveniently timed connections to more than 20 European destinations, providing greater choice and flexibility for both leisure and business travellers alike."

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