The Customs Museum on Susisaari Island in Suomenlinna traces the history of Finnish customs operations from the period of Swedish rule to the present day. The museum is located in the Hamilton–Polhem Barracks. Visitors can explore the exhibits after the season has ended on a guided tour booked in advance. The free guided tour lasts about an hour, and a maximum of 25 visitors is recommended per tour. There are stairs at the entrance and thresholds between rooms, so the museum is not wheelchair accessible.