The film's funniest moments come from the characters' attempts to not only master the magazine's many absurd prescribed techniques for getting boys' attention, but also from their having to teach a mermaid to do the same. Putting their personal feelings towards Raymond aside, the girls attempt to set him up with the mermaid despite interference by a villainous girl who wants Raymond for herself.When the girls aren't on the beach, they're shopping or having sleepovers in bedrooms covered with the marks of teen girlhood: pink bedspreads, pictures of celebrities, and an endless supply of teen magazines. If the girls can get Aquamarine (whose fin transforms into long legs on land) used to life among humans and help her find true love, they may get their wish granted for Hailey to stay. Emerging from the pool with long blonde hair, eyeliner, and sass, the mermaid possesses everything Claire and Hailey lack-confidence, big breasts, and nail polish that changes color with her mood. Unexpectedly coming to their rescue is Aquamarine (Sara Paxton), a mermaid who appears one day at the beach-club that Claire's grandparents own. But their days of carefree giggling will soon come to an end if they can't find a way to stop Hailey's imminent move to Australia.
Claire (Emma Roberts) and Hailey (Joanna "JoJo" Levesque) are inseparable, sharing everything including a crush on lifeguard hottie Raymond (Jake McDorman). Based on the book by Alice Hoffman (PRACTICAL MAGIC), the refreshingly innocent AQUAMARINE follows two 13-year-old best friends through the last days of summer.