Three arms, one lake: how to read Lake Como.

On a map Lake Como is an upside-down Y. One arm runs south-west down to Como, one south-east to Lecco, and the third heads north towards Colico: the upper lake, the Alto Lario. Bellagio sits where the arms meet. Getting this shape into your head is step one, because it decides everything else: where you sleep, which train you take, how much time you spend on a boat.

A few numbers help. The lake covers about 146 square kilometres, which makes it Italy's third largest after Garda and Maggiore. But it is the country's deepest, at more than 400 metres, and it lies entirely inside Italy, about fifty kilometres from Milan. It is fed mainly by the Adda and Mera rivers. Locals call it the Lario.

Getting there

From Milan the train is the easy choice. For the Como arm, leave from Milano Cadorna on the Ferrovie Nord line, or from Centrale and Porta Garibaldi to Como San Giovanni. For the Lecco arm and the mid-lake, trains run to Lecco and continue up the eastern shore: Varenna-Esino is about an hour from Milano Centrale.

By car, take the A9 motorway for Como and the SS36 for Lecco. In high season leave the car outside the centres and carry on by foot or by boat.

Getting around by water

Three kinds of boat work the lake. The battello is slow, has an open deck and is the one for looking and taking pictures. The aliscafo, a hydrofoil, is the fast service. The traghetto is the car ferry of the mid-lake, and it takes foot passengers too: it links Bellagio, Varenna, Menaggio and Cadenabbia.

There is a free-circulation day ticket that lets you hop on and off as often as you like. If you are staying in the mid-lake it is the simplest way to see three villages in one day.

The Como arm

Como is a real town, with its cathedral, its waterfront and the Tempio Voltiano, built in 1927 in memory of Alessandro Volta. From the end of the waterfront a funicular has been climbing to Brunate since 1894: about seven minutes later you are above the town with the first basin of the lake below you.

Further up the western shore comes the Tremezzina, the stretch of the great villas. Villa Carlotta, in Tremezzo, is a neoclassical house with a large botanical garden and rooms of sculpture. Villa del Balbianello, in Lenno, stands on the tip of the Lavedo promontory with water on three sides: in 1988 its last owner left it to FAI, the Italian heritage trust, which opens it to visitors. Its loggia and terraced garden appeared in Star Wars and Casino Royale.

Off Ossuccio lies Isola Comacina, the lake's only island. It was destroyed by Como in 1169 and is now an archaeological site, with the remains of the basilica of Sant'Eufemia. On the Sunday closest to 24 June, for the feast of San Giovanni, the lake fills with a procession of boats and fireworks.

Walkers have the Greenway del Lago: about ten kilometres through villages, gardens and olive groves along this shore, easy enough for anyone.

The Lecco arm and the mid-lake

On the eastern shore, Varenna is a fishing village that has stayed small, with coloured houses, stairways and a lakeside walk. Boats leave from here for Bellagio and Menaggio, and it is the handiest way in for anyone arriving by train from Milan. Lecco closes the arm at the bottom, between the lake and the mountains.

What to eat

Lake fish first: risotto with perch, and missoltini, shad that are salted and dried and eaten with polenta. Olive trees grow on these shores, and Laghi Lombardi Lario oil has protected status.

How long you need

A day trip from Milan covers one arm only: Como with Brunate, or Varenna and Bellagio. Three days give you the mid-lake at an easy pace and a villa a day. The classic mistake is trying to drive the full loop: the road is long and narrow, and the lake seen through a car window is not the lake.