Extra winter capacity is being laid on by Finnair from the UK and Ireland.
More flights will be added to the Heathrow-Helsinki route from November 27 November plus additional frequencies from Manchester and Dublin from December 3.
Seven additional flights between Heathrow and Helsinki will run from December 17 to January 2 in addition to a new weekend service starting on Saturday.
The airline will re-introduce larger wide-bodied aircraft at certain times to meet improved demand, with extra capacity on Airbus A330s and A350s.
Manchester and Dublin will gain an additional return flight on a Friday between December 3 and 17 and on January 7.
An Edinburgh-Helsinki route will continue to be served three times a week during the winter.
UK, Ireland and Benelux general manager Andrew Fish said: “We’re excited to continue our recovery and re-establish our popular frequencies from the UK and Ireland in line with customer demand for flights to Finland over the festive season.
“Finnair customers will be able to enjoy further flight flexibility when travelling for business or leisure from London to Helsinki, thanks to extra capacity for travellers eager to experience Finland’s winter period.
“We’re also pleased to be introducing extra seats on our Manchester and Dublin services to Helsinki to provide greater regional connectivity from the north of England and for our Irish customers.”