Take line U3 to the station "Zippererstrasse". Change into the streetcar (tram) and ride to the next stop "Molitorgasse". The office building CITYPORT11 is to your left.
Take line 71 starting on the Schwarzenbergplatz (city center). Leave the streetcar at the 7th stop ("Molitorgasse") and you'll be right in front of the CITYPORT11
Information and schedules for public transport is available at: www.wienerlinien.at