Zollbrücke Rheinau is a Rhine river dive entered from the municipal Salmenwiese beside the bridge, where the riverbed, bridge piers, and undercuts create a compact freshwater route with fish refuge. It suits divers who are comfortable with river rules and weather checks, because the site rewards patient, small-group planning more than big-water exploration. When the river is in shape, visibility can be very good and large catfish are a summer highlight.