Monterosso has its own railway station on the Genoa–La Spezia line, and this is far and away the easiest way to arrive. Trains from La Spezia run frequently (about 20 minutes); from Genoa the journey takes around an hour and a half. The station sits in the Fegina district, a short walk from the beach and a tunnel away from the old town.
Ferries run seasonally from Genoa, Lerici, and La Spezia, docking in the small harbour at the old town. This is a fine way to arrive if the weather is calm — the view of the village from the water is as good as advertised.
Driving is not recommended. The road into the village is narrow and congested in season, and there is essentially no parking in either the old town or Fegina. Cars must be left in the hilltop car parks above the village and a shuttle or steep walk taken down. Unless you are arriving from somewhere inaccessible by train, leave the car elsewhere.