There are several docks where one can get on or off the boats, but the main one is in the center of Basel.
How to reach the boat dock
The main boat dock is called 'Schifflände'. It is located next to the bridge ('Mittlere Rheinbrücke') in the old town center. It can be reached in a 20 minute walk from the rail station Basel SBB, or in 15 minutes by tram.
The little ferries depart from 4 different locations in town. See their website for details.