Scandinavian Airlines will start a seventh daily flight between Heathrow and Stockholm on March 28.
The airline said it was responding to increased demand from both business and leisure travellers.
The fight (SK529) originating in the Swedish capital departs at 12.55pm, arriving at Heathrow at 2.35pm.
The return leg to Stockholm (SK530) is scheduled to depart at 4.35pm, touching down at 8.05pm
SAS has also changed its early morning departure from Heathrow from 6.55am to 7.15am.
Meanwhile, Finnish airline Blue1 - past of the SAS Group - will start a second daily flight between Heathrow and Helsinki from April 25.
The London to Helsinki flight (KF558) takes off at 8.05am, landing at 1.00pm. The return leg (KF557) leaves Finland at 8.15pm, arriving at 9.25pm.