The station has four platforms. Platform 1, which is out of use, is joined to the station building. Platforms 2 and 3 form an island platform and are for trains to Amersfoort and Amsterdam. Platform 4 is used for trains to and from Utrecht Centraal.
In the early days, the HSM had a railway station, for trains to Amsterdam and Amersfoort, this was on the Oosterspoorweg, and the nearby station Baarn Buurtstation, which was for the train to Utrecht. In 1938 the companies became part of the station NS, however Baarn Buurtstation was not closed until the Stichtse lijn was electrified in 1948. The station was rebuilt, with a platform 4 for the Utrecht train, to prevent delays of Intercitys passing through the station. Since March 2009, platform 1 is no longer used for passenger services.