Littering and other thoughtless behaviour can easily spoil the appearance of the fortress, so please use the litter bins that have been provided. There is a year-round prohibition on fires and barbecues. Visitors are not allowed to remove parts of buildings, bricks, stones, timber or other loose objects from the fortress.
The fortress is not especially adapted for disabled people, but work has started on finding solutions for improving disabled access. Large areas of Karljohansvern are relatively flat, with tarmac roads and walking paths. Getting around the area is therefore not especially challenging. Most attractions are at street level, with relatively easy access. There is a lift and a disabled toilet at the National Museum of Photography in Depot A.