Well Wikipedia helps explain what a nude beach is just in case we wanted to know a little in dept info about it!
A nude beach is a beach where users are legally at liberty to be nude. Sometimes the terms clothing-optional beach or free beach are used. Nude bathing is one of the most common forms of nudity in public. As beaches are usually on public lands, any member of the public is entitled to use the facilities without membership of any movement or subscription to any philosophy. The use of the beach facilities is normally anonymous. Unlike a naturist resort or facility, there is normally no membership or vetting requirement for the use of a nude beach. The use of nude beach facilities is usually casual, not requiring pre-booking. Nude beaches may be official (legally sanctioned), unofficial (tolerated by residents and law enforcement), or illegal. However, nude beaches are relatively few and some distance from cities, and access is at times more difficult than at a regular beach and the facilities at these beaches tend to be very basic.
Now why would you even think of going to a nude beach?
People visit a nude beach for any of a number of reasons. These range from people who see no reason to wear clothing when taking part in water activities or sunning, or who enjoy being nude or partially nude . Some people visit a nude beach because they enjoy looking at people who are nude, or because of curiosity. Some people sunbathe on a nude beach to get a more even suntan, and to eliminate tan lines. Some people sunbathe at a nude beach to get an all-over tan, but do not have access to a private place where they can sunbathe, such as a back yard not visible by neighbors.
Now is this Legal? Well......Most beaches around the world, including nude beaches, are on public lands. That means that though private resorts and hotels that adjoin a beach may enclose their property behind fences with controlled access, most countries do not allow private ownership of the actual beach area. Thus, while a resort can control access and set clothing standards on its property, these standards would not necessarily apply to the beach itself, which remains subject to local laws or customs, and public access to the beach itself usually remains unrestricted. This applies, for example, to the islands in the Caribbean, Mexico, and Florida. On the Seven Mile Beach in Negril, Jamaica, for example, though the beach is lined with private resorts with fences down to the sand/waterline, the beach itself is open to the public. Though actual clothing standards vary from resort to resort, the beach area is officially designated as "TopFree", and public access is unrestricted.