Together with the Carnival of Venice, the Carnival of Viareggio is the most famous Italian carnival. It takes place every year after Lent between January and February and it is characterized by a parade of allegoric carts and by a range of collateral events linked to this festivity that enlivens the town for thirty days.

The Corsi Mascherati develop on a ring-shaped path. They are carts and groups of masked people that walk on this track several times. The track is about two kilometres long and it crosses the sea front, too. The thirteen carts (nine of them belong to the first category and the others to the second category) and the "masked groups" are spaced out and accompanied by music bands coming from all around the world and by majorettes and other animation groups. The walks repeat five times in one month, four times on Sunday during the day and only once on the night of Shrove Tuesday. Each time, the groups parade for more than two hours and a jury judges them and awards one of each category.
The "Burlamacco", the symbol of the Carnival of Viareggio, is a mask the painter Uberto Bonetti conceived and created in 1931. It is a sort of clown that embraces all the characteristics of the of some of the most famous masks of the Italian "Commedia dell'Arte": the patched clothes of Arlecchino, the ponpon hat of Pierrot, the cloack of Balanzone and a hat that recalls Rugantino. The mask was given its name eight years later and Buffalmacco, one of the painter's colleagues who had also been cited in Giovanni Boccaccio's Decamerone, suggested it to Bonetti.
The celebrations of the districts started with the Carnival and they stem from a long and ancient tradition. Each quarter in Viareggio has its own celebration. They take place in turns as soon as the main street of the district is closed and inside dinners and dances last from the evening at seven until midnight. Tourists and extras wearing masks that needed months of study and preparation can be met. They toast, dance, sing, and renovate one of the most ancient festivals still existing today with joy.
The masked balls, instead, are the celebrations of the high society of Viareggio. Once they took place only in luxury residences or in the meeting places of the rich bourgeoisie, such as the Pacini Theatre or the Regio Casiṇ. They were sumptuous parties that started with a supper and ended with balls in the dawn and some competitions for masks spaced them out. From the 70's on, also more "popular" ones have been held in various areas also outside the city's limits.