Romania's largest hybrid carrier Blue Air has launched three times weekly flights from Birmingham to Cluj, the second largest city in the Eastern European country.
The second route follows in quick succession from the airline's inaugural Bucharest launch in March.
Birmingham Airport said this route had been so popular that its frequency would increase from two to three flights per week from the start of winter.
Tom Screen, head of aviation development at Birmingham Airport, said: "Blue Air has had a very successful few months at Birmingham Airport, flying thousands of passengers to and from the Romanian capital city of Bucharest.
"We are delighted that they are already introducing this second route to Cluj.
"The city is a cultural and historic centre home to universities, vibrant nightlife and landmarks dating to Saxon and Hungarian rule.
"We look forward to seeing the carrier continue to go from strength to strength here at Birmingham Airport."
Tudor Constantinescu, chief commercial officer at Blue Air, added: "We are extremely pleased to announce our second route to Birmingham starting in December this year, as we expand the network from our newest base at Cluj-Napoca.
"The growth of tourism and trade between the UK and Romania, and especially Cluj-Napoca which recently has rapidly been emerging, means we have no doubt that this new route will be another success.
"We look forward to continuing working closely with Birmingham Airport to ensure the longevity of this new service."