Østerport station is listed and thus represents some of the best of Danish architectural culture. The station was designed by DSB's chief architect Heinrich Wenck in the late 19th century. The conversion has been carried out while maintaining full train operation, which has placed great demands on logistics, procedures and planning of the renovation project. The number of passengers at Østerport Station is expected to increase from 30,000 to approx. 45,000 travelers daily after the opening of the City ring, and the new renovated Østerport station accommodates this. The building and the forecourt have been thoroughly designed to create space for the growing passenger flow that is created between buses, S-trains, the Coastal Railway and the Metro.

Two new entrances have been made in Østerport Station, one in each gable, which creates access to bus traffic at one end and the metro at the other. The descents to S-tog and Kystbanen have been retained, but the walkway area in the central passage of the station building has been expanded by removing several load-bearing walls and replacing them with columns. At the same time, the original architectural qualities have been integrated and reinforced after the conversion. Great emphasis has been placed on using materials like the originals and recreating the color attitude. The architectural work has been planned and carried out in close collaboration with the Danish Agency for Castles and Culture.

During the process, serious joint damage occurred in the western gable. Damage to the foundation meant that the entire west gable was registered, taken down and put in storage, so that the building's foundation could be repaired. The gable has then been rebuilt based on meticulous registration. The truss constructions underwent repairs and, in certain instances, were entirely replaced. A new slate roof was installed, accompanied by a comprehensive renovation of the roof structure. The deck construction supporting the entire building received reinforcement. Simultaneously, the two existing tunnels have been upgraded with new surfaces on the floor, walls and ceiling as well as time-lasting and modern lighting.

The original double-height arcades against the building's two handsome barrel vaults have been exposed and have had their original arched blasting restored. New oak columns have been added and all the walls are made of wood, straw and plaster.

The station's original color palette has been recreated. Drawing inspiration from old illustrations and color archaeological studies, the station's interior has reverted to its original design from 1897. The woodwork is now painted in a consistent red and green color theme, complemented by accents of yellow and blue on selected carpentry details.

Fine friezes along the ceiling have been exposed and revitalized, retaining their original color scheme. Every effort has been made to restore the original ceiling heights by eliminating multiple layers of suspended ceilings.