By plane: From Vienna International Airport (ca. 20km outside of Vienna) there are several modes of transport available for getting into the city centre:
-Taxi (from 25 Euros to around 40 Euros)
-Airport bus (from 6 Euros)
-CAT (Airport Shuttle Train, 15 minute journey to Wien-Mitte (Vienna Central Station) – single ticket 9 Euros http://www.cityairporttrain.com
-Tram (S Bahn), 30 minutes to Wien-Mitte (Vienna Central Station) – single ticket 3 Euros www.oebb.at
Then from Wien-Mitte, travel two stops with the underground U4 Hütteldorf line to Karlsplatz.
By train:
Arrival from the Westbahnhof (West Station) – travel 5 stops with the U3 Simmering line to Stephansplatz, then change to the U1 Leopoldau line and travel two stops to Karlsplatz.
By car: Follow signs for the Zentrum (centre). Nearest landmark is the Vienna State Opera.