From Venice's Marco Polo International Airport you may take the ATVO bus to the historic city center. You may also take a taxi which reaches Piazzale Roma in 15 minutes, or choose the more expensive water taxi.
Another option is to take an airport link arrival transfer and the airport link departure transfer.

Many low cost flights also fly to Treviso San Giuseppe Airport, from where you need to take an ATVO bus to reach the city, taking about 1 hour and 15 minutes.

If you arrive by train, your station is Santa Lucia from where you can walk to almost anywhere in the city.

Venice is to be explored by foot but if you need to cross any of the canals fast, take one of the Vaporettos. Number 1 can actually be taken as a touristic ride, as it travels along the Grand Canal.

Going elsewhere after Venice? Check car rental rates here.