Starting in Berlin:
Option 1.
Via the motorways A 24 and A 19 towards Rostock. At the cross Rostock change to A 20 towards Stralsund until the exit Stralsund. Follow the signs for the island of Rügen (Sassnitz) on the B 96.
Option 2.
Via the A 11 in the direction of Szczecin until the Triangle Uckermark. Then take the A 20 in the direction of Neubrandenburg/Stralsund until Exit 24 Stralsund. Bundesstraße B96 towards Stralsund follow the signs to the Island of Rügen.