It was originally envisaged that its main role would be as a "picnic railway" providing access for city-dwellers to the beaches between Brøndby Strand and Hundige, but after the first phase was completed it became evident that transporting commuters were more important.
The abandoned area reservations from Ishøj until Olsbækken in Greve can still be followed on a modern map.
A new high-speed railway, Copenhagen–Ringsted Line, has been built parallel with Køgebugtbanen continuing to Ringsted, opened for traffic in 2019.
This line has a stop at a new station, also with a stop along Køge Bugt-banen, located between Ølby and Jersie Station, which serves as an exchange point between the new line and Køge Bugt-banen.
The basic service pattern consists of the A service which runs until Hundige and stops at all stations, and E, which runs partially non-stop until Ishøj and then stops at all stations until Køge.