The Secret of Mermaid Island - The Mermaid Island Trilogy, #1

Bonnie Campbell vows to make the best of a summer spent away from her school friends on remote Mermaid Island. Things get more interesting when Bonnie discovers the island is the home of a famous celebrity, but as time passes she begins to suspect that Mermaid Island may hold an even bigger secret. Is it possible the island has a real mermaid? Bonnie and her friends return in The Mermaid's Gift and Mermaid Dreams.