Difference between vaporetto & water taxi?

water taxis = private taxi, vaporettos are the public transport system on water. You cannot buy a water taxi pass. You can buy a vaporetto pass. Water taxis are VERY expensive.

Vaporetto information can be seen here: http://www.actv.it/english/home.php

Tim is correct. On the ACTV website, the vaporetto is called a water bus in English. The vaporetto is a larger and slower boat that holds about 60-80 passengers (most standing). Vaporettos are public water transportation with fixed routes. The water taxi is a small private boat that holds up to 6 passengers and operates like a taxi. It has no fixed routes. Tim is also correct that water taxis are expensive. Fares begin at 100Euro but can be shared amongst the passengers. Tim is also correct that you can buy a vaporetto pass for a certain number of hours. I don't know about a pass for a couple of weeks.

Giudecca has five vaporetto stops. You might want to contact your accommodations people to ask which one is the one you need to get off at. If you are near the Palanca stop, you can always jump on the free Hilton water shuttle (just look like a guest) that departs every 30 minutes for St. Mark's square.

Just be cautious if you have an early flight out of Venice Marco Polo and you need to get there from Giudecca. You may indeed need the expensive water taxi for the high-speed James Bond ride through Venice as the sun begins to rise.

Think of it this way. Water Taxis are just like Taxis in any other city (except they're boats) and Vaporettos are the equivalent of the local bus system in Venice. The usual calculations of speed and convenience on the one hand versus a lower price and less quick/slightly less convenient (in most cases) service on the other apply as they do in most cities.