The Beach theme was released by the original game developers at the start of YoWorld, formerly known as YoVille. It was one of the first furniture lines.
The basic set had a mixture of beach furniture such as deck chairs, some beach decorations like seaweed and towels, and wicker furniture. There are a total of 37 items in this furniture line, including the beach wallpaper.
There was another theme in 2010 which was also called Beach. The two are unrelated and shouldn't be confused with each other.