The Gate can be visited
Town Fortification Wismar-Wasser Gate

The Wassertor (Water Gate) in Wismar is a brick Gothic structure and the only surviving one of the original five city gates of the historic city fortifications. It served as a direct harbor gate, providing access from the port into the city.
History+
The Wassertor was constructed around 1450, during the late Gothic period. It features a large pointed arch and a square tower with a gabled roof. The city side is adorned with a stepped gable with battlements and six narrow blind arches, while the harbor side has had a triangular gable since a renovation in 1600.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: https://commons.wikimedia.org/wiki/File:Wismar-Wassertor.jpg
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 53.8963, 11.4614