Coco

Coco is the Mermaid Princess of the South Pacific Ocean. She is shown as a kind and gentle person with a sunny and bright personality in the manga. However, she is shown to be rather rash and loud in the anime. Coco also loves hanging out with boys in the anime version of MMPPP. She is not shown in the first story arc [except the end] because she had been captured by Gaito and his Dark Lovers [really, how can you be captured by -Gaito and the Dark Lovers-] Coco is very good friends with Sara, and she is extremely loyal to her. Coco's idol form is Yellow Pearl Voice.

Noel

Noel is the Mermaid Princess of the Artic Ocean and the elder twin between her and Caren. Noel and Caren were both born at midnight on the opposite sides of the Earth's poles [Noel on the first part of midnight and Caren on the later part]. This may explain the reason why Noel and Caren are "polar" opposites when it comes to personality. Noel is very calm and she has a very gentle, caring personality [unlike Caren..]. She does not act implusively, unless she has to protect her friends. Noel's kingdom was destroyed by Gaito and she met up with Rina, who was also fleeing. They both vowed to search together for the other Mermaid Princesses. Shortly after, Gaito caught up with them and Noel was caught because she sacrificed herself so Rina could escape. Later on, Caren blames Rina for Noel's capture. She spends most of the first season asleep in Gaito's castle. Her idol form is Deep Blue Pearl Voice.

Caren

Caren is the Mermaid Princess of the Antartic Ocean and the younger twin sister of Noel. Her attitude is the total opposite of Noel's. Even though she never met Noel, Caren cares for her a lot and vows to rescue Noel when she heard that she was captured. When she meets Lucia, Hanon, and Rina, she only helps them from afar and doesn't reveal her identity until later. She also said that she had no intentions becoming their friend and she blames them [Rina especially] for Noel's capture. Caren decides to resuce her sister by herself, but things don't happen the way she planned. Caren's idol form is Purple Pearl Voice.

Sara

Sara is the former Mermaid Princess of the Indian Ocean. Sara and Taro had a secret relationship, but her caretaker would not let Taro meet Sara. When Taro does not show up, she gets heartbroken and angry. She unleashed a huge wave that destroyed her kingdom and that wave killed Kaito's parents and thats when Lucia saved him. Being ashamed of herself Sara goes to Gaito and her hair turns black because of that. Gaito fell in love with her and decided to help her to get revenge on the entire marine world. Later on in the series, Sara finally learns that Taro stil likes her when she captured him and took him to Gaito's castle. Her hair turs orange and again and she helps the other Mermaid Princesses fight Gaito. When Aqua Regina comes and seals the castle once more, Sara goes and stays with Gaito as a punishment for what she did. Sheappears as a spirit in Lucia's dream and guides her. Will there be another Mermaid Princess of the Indian Ocean, Orange Pearl Voice?!

Siera

Siera is the new Mermaid Princess of the Indian Ocean. Before she was born, however, an angel named Michel steals her heart. She appears in Lucia's dream and tells Lucia to find the fragments of her heart so she can be born. Eventually Lucia, Hanon, and Rina find all of the fragments of her heart and she is born. The orange pearl is also returned to her. So now she is the Mermaid Princess of the Indian Ocean and her idol form is now Orange Pearl Voice. She is also, now, the youngest of the Mermaid Princesses.