Mittenwald sits on the Mittenwaldbahn — the scenic railway line between Munich and Innsbruck that runs through the Karwendel range. Direct trains from Munich Hauptbahnhof take about 1 hour 45 minutes, with a change at Garmisch-Partenkirchen. From Innsbruck it is closer to 50 minutes, passing through the spectacular high-Alpine pass at Scharnitz.
By car, the A95 from Munich brings you to Garmisch in under 90 minutes; from there a 30-minute drive on the B2 reaches Mittenwald. There is paid parking at the edge of the pedestrianised old town. Munich Airport (MUC) is the most useful airport; Innsbruck (INN) is closer but has fewer connections.