The Fraueninsel is an island in Lake Chiemsee and can only be reached by ferry.
Ferries leave every hour or every 30 min from different cities on Lake Chiemsee, including Gstadt (every hour), Prien/Stock (Hafen) (every 30 min) and Bernau/Felden (every hour). Please see the timetable of the Chiemsee Schifffahrt
Getting there by car: Car parking next to the ferry terminals is possible in Prien, Gstadt, Seebruck, Chieming and Bernau/Felden.
Getting there by train: take a train to Prien Bahnhof. From there, take the Chiemsee Bahn to Prien/Stock (Hafen) (once per hour), from where the ferry leaves to Frauenchiemsee (once every 30 min, 30 min trip)