Old military fortress surrounded by water, Kastellet is nowadays being used for commercial purpose (seats of few companies) instead of being opened for public. More likely you will enjoy the surroundings which consists of tidy nice park with narrow paths ideal for walk with a buggy. Public transport will get you there fairly easily, either by bus (line 26 Osterport station; 1A Esplanaden station), metro or the city train (Osterport station). Don’t look for public restrooms...
Old military fortress surrounded by water, Kastellet is nowadays being used for commercial purpose (seats of few companies) instead of being opened for public. More likely you will enjoy the surroundings which consists of tidy nice park with narrow paths ideal for walk with a buggy. Public transport will get you there fairly easily, either by bus (line 26 Osterport station; 1A Esplanaden station), metro or the city train (Osterport station). Don’t look for public restrooms or refreshment stand anywhere in the park, there is none. So rather enjoy the walk to Little Mermaid and then continue back to the city centre.