Go for a dip in the ocean with any of our mermaid costumes. At Halloween Costumes.com we offer a great selection of mermaid costumes from adult to child sizes. Your little girl will enjoy dressing like her favorite Disney princess in our Ariel costume from the movie The Little Mermaid. Or, dress yourself as the Disney princess in a sexy version of the costume. Feel the magic under the sea this Halloween season with any of our mermaid costumes!