The beach is the reason Forte dei Marmi exists as a resort, and it is a very particular kind of beach. Almost the entire seafront is divided into numbered bagni — private beach clubs — where rows of matching striped parasols and wooden cabanas are rented by the season or by the day. Families have held the same spots in the same bagno for three or four generations. Day visitors can almost always find a sunlounger for hire; the clubs also provide showers, beach bars, and waiters who bring cold drinks to your chair. A narrow strip of free public beach (spiaggia libera) exists at the northern and southern ends of the waterfront.
The sand is fine and pale — unusually white for the Tyrrhenian coast — and the water is clean and shallow close to shore, shelving gently enough to be safe for children. The backdrop of the Apuan Alps is exceptional: on clear days the snow-capped marble peaks are visible directly behind the town, a striking counterpoint to the blue sea.