There are 3 lines for the metro, 19 tram and 97 bus : M1 = red line (Duomo, San Babila, Castle…)
M2= green line ( Station Centrale, Station Garibaldi, San’t Ambrogio…)
M3 = yellow line (Duomo, Station Centrale, Montenapoleone…) and an others line of train which goes in the peripheria.
The metro works from 6 to 00,30 every day, the tram from 4,30/6 to 1,00/2,30 and the bus from 5,30/6 to 00,30/1,45. There are two buses which goes all night long : the 90 and the 91 (review public transport by night). At all stations there arelots of metro and buses and tram, you can see how long you will have to wait for the next one. in the metro, they even say every half a minute! They are quite accurate.
On week-end’s night, the bus has the same schedule as the metro and there are also other lines of bus available (see review public transport at night).
One ticket costs €1,50 and is valid for 90 minutes. You can take the bus, the metro and/or the tram with the same ticket.
Be careful if you want to go a little further than Milan (for example to the fair in Rho), you will have to buy the ticket “interurbani” which price depends on how far you are going.
If you are in Milan for a few days, you might want to buy a 24h hours’ ticket or other pass.
Find all the information here!
You can also use their website to see which transport you have to take to go from one point to another at a determined time and how long it will take.
On a another hand, there is also a service of Bike sharing: you can rent bikes to go from station to station. You can buy an subscription for a day, a week or a month. More info on how this works can be found here!