You are required to have a ticket on you at all times while on the Rome metro system. Rome has instituted tough fares for fare evaders up to €200 and there are frequent inspections of your ticket.
Single fares called BIT tickets are €1.50 for adults and can be used for unlimited transfers between the metro, buses, trams and urban trains for 100 minutes. However, once you exit the metro system, you’ll have to buy a new ticket to re-enter.
2) Day Passes
There are one day (€6), three day (€16.50) and weekly (€24) transit passes available for unlimited public transportation until midnight of the day the pass expires.
3) Roma Pass
Along with the three day pass, there is also a Roma Pass available for three days at a cost of €36. Included with your free bus and metro travel, you get discounted museum and monument admissions.