On cruise ship days, Melbourne put a bus 109 to take you to the city, so as to not overload the tram with cruise ship passengers, it is the same cost but leaves from on the pier which saves walking the 300m to the tram stop. The 109 bus takes you to the 124A tram stop, which is by the casino on the south bank. From there you can get free trams around the CBD or walk to the DFO.