This question already has an answer here:

I will travel to Italy in one month (to Venice) and I would like to buy a SIM card so that I can access internet during my weekend stay. What options are available and which ones do you recommend? I have an iPhone 5S and my home operator is Vodafone.

merged by mindcorrosive Jan 21 '14 at 19:04

This question was merged with Prepaid Data Plan for cell phone in Italy because it is an exact duplicate of that question.