The main access to the lake is from Milan and Bergamo. It is also possible to cross the border from Lugano Switzerland, and arriving at the lake at Menaggio. In the North, the lake can be accessed through the Splügen pass closed from end of autumn to the beginning of spring, or from St. Moritz, both entering from Switzerland.
By train
Regular trains run from Milan to Como beware it has 2 stations: Como San Giovanni and Como Lago. Trains also run from Milan and Bergamo up the Eastern Shore from Lecco to Varenna and Colico and then on to Sondrio and St. Moritz. Station Como San Giovanni is a little bit outside the downtown, but there are a number of buses that stop there, and one can buy tickets at the Tabac in the station for a few Euros, or walk to the center of town.
Overnight sleeper trains run from Amsterdam via Duesseldorf, Cologne, Frankfurt and Basel stopping at Como San Giovanni on their way to Milan. Similar daytime trains also run.