Taxis in venice

A taxi (or any other type of road transport) will only get you to the edge of the island, Piazzale Roma to be precise. After that it is water transport or on foot.

If you mean a water taxi that will take you closest to your hotel figure €100plus or minus depending on where your hotel is.

As Christi pointed out, a private water taxi will take you directly to your hotel (assuming it has a water landing), otherwise it will drop you off close by. We used a private water taxi in 2013 as our hotel had a water landing and will use it again this coming August when we stay at the same hotel. It was definitely worth the money as we had flown all the way from California and were exhausted upon landing and simply wanted to get to our hotel fast. The public water bus would have taken much longer not to mention we'd have to fight to find space for us & our luggage and then we'd have to make our way over bridges with our luggage, etc., and sometimes there's only standing room on the public water bus. If you do opt for a private water taxi, don't forget to pay for it before you leave the airport terminal. Unfortunately, I didn't do this and we walked all the way out to the dock only to find out I had to pay for it inside the terminal and then had to walk all the way back!