The cruise port is located in the town of Wismar, about 1 mile away from the city. No public transport is awailable. The port area isn't really friendly or yet touristy, unlike the city inself with beautiful hanseatic buildings.
Since Wismar is located close to Lubeck, Rostock and Schwerin, visits to any of 4 towns can be combined. All of those have the great 13th century charm and beauty.