SAS started serving Copenhagen from Stansted yesterday in addition to Heathrow.
Five flights a week are scheduled to the Danish capital from Stansted, rising to a daily frequency from July 1.
The new Copenhagen connection adds to five daily returns operated by the airline from Heathrow.
Fares from Stansted start at £45 one way or from £80 return in SAS Go Light for passengers with carry-on bags only.
SAS Europe general manager Niko Ek said: “We continue to see an increasing demand for flights to Copenhagen from the UK and are delighted to offer our customers the option to fly from both London Heathrow and London Stansted.
“For Danes, a choice of arrival airport into London will also offer increased convenience”.
Stansted aviation director Mats Sigurdson added: “It’s great news SAS has returned to London Stansted with the launch of this new service to Copenhagen.
“The service will not only provide passengers from London and the east of England with even more choice to an exciting European destination but it also opens up a host of excellent onward connections across the SAS network, including Beijing, Singapore, Honk Kong, Shanghai and Bangkok.”