Vaporetto

It is €7, also make sure you validate it by placing it on the small yellow machine before you board. A green light lets you know you have validated it and you are good to go!
The actv site gives all the details and what the machine looks like

http://www.actv.it/en/imob/imob

Shelley, last I saw it was 7Euro. You can purchase passes in 12hour, 24hour, 36hour, 48hour and 72hour segments. You can see these options on www.veniceconnected.com

The passes make sense if you're going to ride the vaporetto two or more times a day. If you get a pass, you must validate it EVERY SINGLE TIME YOU BOARD by tapping it on that little pad. It's how they discourage cheating.

The passes also make sense if you plan to go out to the other islands in the lagoon, especially Burano and Torcello. I've found it's very nice to have a pass and just jump on and off the vaporettos without worrying about paying, waiting in any ticket line, or whether a particular trip is really worth 7 euros to you. As I think about it, 7 euros is really high for a short trip, if you think of it like a city bus.

When you buy a pass you can also get something of a discount on the airport bus, if you plan to use the bus arriving and/or leaving.

I have an esoteric question related to this: I will be in Venice in late May, arriving one afternoon, spending the next three full days, then flying out the next morning. Planning to get a 3-day pass. Does anyone know, can I use the vaporettos during those three full days, then use the airport bus ticket on my final morning, or does the bus ticket expire when the vaporetto pass expires?

Thanks, other Larry

And not all stops have a ticket stand making a pass great

I believe the 3-day is for 72 hours after first validation.