A train ride between Monte-Carlo and Cannes takes just over an hour and costs € 8.90 per person (one way, second class). Trains run very frequent (2-3 per hour). From the train station in Cannes, you can easily explore the rest of the city on foot. It's good to check the train timetable in advance.
How do I get to the train station from the cruise port in Monte-Carlo?
The train station is located in the west of town on the slope of the ridge at Pont Sainte-Dévolte and Avenue D'Alsace.
It's pretty tough to go there on foot, though there are different elevators in Monte-Carlo that help you to make the steep hike. You can also take bus N° 2 from Monaco Ville. This makes a stop at the train station and the Office de Tourisme bus stop.
TIP: The train station of Monte-Carlo consists of several floors. When you pass the main entrance, take the escalator down to the platforms.