From Venezia Santa Lucia train station to Piazza San Marco
Actv Vaporetto boat service:
Exit straight out of the train station to the Grand Canal, find the Actv water bus (vaporetto) docks, take line 2 down the Grand Canal (in the direction of Rialto) direct to San Marco Giardinetti or San Marco San Zaccaria stops. The vaporetto ticket is 7.50 Euro per person one way. There are also available 1, 2, 3 and 7 day passes from Actv for use all over the city and the islands around.