Four trains per hour will take you from the main train station in Vienna to the Designer Outlet Parndorf. The trip will take you about 30-40 minutes. The train station, where you have to get off is named “Parndorf Ort”. More detailed information are provided by Designer Outlet Parndorf here.
By shuttle bus:
There is a shuttle bus, which runs daily from Vienna to Parndorf on demand. The station/meetingpoint in Vienna is just opposite the State Opera (15min away), Opernring 3-5, and takes you to the Designer Outlet and back to Vienna. More detailed information are provided by Designer Outlet Parndorf here.