For more than two centuries the sluice harbour was the heart of a vibrant fishing and shipping community. With up to 1500 ship movements a year, the harbour was marked by constant activity. After the construction of the pumping station and the harbour in Harlesiel in 1959-60, the harbour in Carolinensiel rapidly lost in importance. The harbour ceased to be needed for the shipping and fishing industries and soon silted up. The new land was paved and used as a parking lot.

With the establishment of Sielhafenmuseum in the early 1980s the harbour was reconstructed in its original form a was given a new lease on life. Today it is the home port of a number of historic sailing vessels and, together with the historic buildings around the harbour, an excellent reconstruction of life in the past.