Prince Antonio is the deuteragonist in the 2007 animated film, Barbie as The Island Princess. He is Rosella's love interest, and later her husband at the end of the film.
While Antonio was exploring one day, he came across Rosella's island. Rosella was a girl who was thrown overboard during a storm 10 years before, and gained amnesia. Her only memories were of the island, and she considered the animals she encountered there her family. She even learned to talking to animals. When Antonio and his friend, Fazer, were getting attacked by crocodiles, Rosella was saved them by telling the crocodiles to leave them alone. Amazed by Rosella's ability to speaking with animals, as well as her personality, Antonio quickly took a liking to her. Antonio asked Rosella if she would like to come back to civilization with him to pay back for saving his life, and Rosella agreed. On the boat ride back to Antonio's kingdom, Apollonia, he fell in love with Rosella.
Once they were back in Apollonia, he introduced her to his three younger sisters Rita, Gina, and Sophia, Antonio and Rosella found out that Antonio had been betrothed to Princess Luciana. Luciana is a sweet, polite girl who was able to see that Antonio was really in love with Rosella. Luciana tried to taking her mother, Ariana, that Antonio was not in love with her, but her mother wanted to takes over Antonio's kingdom; this would be revenge for Antonio's parents banishing Ariana and her family from the kingdom. Antonio and Luciana are became a good friends, but they were just not in love with each other. At a ball, Antonio danced with Rosella and asked her to stay in his kingdom with him. Rosella declined the offer, because she thought he and Luciana should be together.
Antonio let Rosella leave, and his father told him he had to marry Luciana in two days. Antonio was annoyed with his father pushing him into marriage, and he wrote a letter to Rosella asking her to sail away with him. Tika, one of Rosella's animal friends that accompanied her to Apollonia, was jealous of Rosella and Antonio's love, so she hid the letter. However, Ariana spread a disease to the animals in Apollonia, planning to blame it on Rosella's animal friends. Rosella was thrown in a dungeon, and Antonio was furious. He begged his father to release Rosella, but his father would only agree with Antonio married Luciana. Antonio reluctantly agreed, and Rosella was freed, but banished from Apollonia. On the way back to her island, there was a storm, so Rosella and her friends were thrown overboard.
Rosella regained some memories, such as her full name, as she had thought it was just "Ro". She managed to get back to Apollonia to try and save the animals. Rosella interrupted Antonio's wedding and told everyone that Ariana had poisoned the animals and was planning to poison everyone at the wedding with the food. His father, King Peter wanted to put her in the dungeon again, but Antonio reminded him of the deal they made. Queen Ariana tried to convince them that Rosella was dangerous, but Luciana finally saw past everything and eventually confirmed that what Rosella was saying was true. Antonio and Rosella so reminded of Ariana, a woman who only one was crafty as putting on poisons onto the wedding cake. The problem needs to be solved, Antonio wants to make Ariana taste cake for eat.
Ariana cannot asking to eating poisonous foods at all, watched the three rats poisoned dead by the cake and escape from the kingdom with a pain. Although Antonio and Rosella were drop down by Ariana, so they stood up right away. Ariana intentionally to bumps the two teenage women then mocked them, Antonio must hurry on to save them by two and Rosella and Tika are walkout to chase Ariana. Soon after, Rosella has captured Ariana and she was taken away. Luciana stay with Antonio, succeeded her mother as the queen, tell him that they are never getting married for was it. Honestly, Luciana told Antonio that someday, someone would look at her the way he looks at Rosella. Antonio asked Rosella to marry him and though she declined at first, she agreed after finding out Luciana would happily accept it. Antonio's father welcomed Rosella into the family, and Rosella told everyone her real name.
A wedding guest, Queen Marissa mentioned she had a daughter named Rosella, and she and Rosella reunited after 10 years. Soon, Rosella and Antonio got married and the happy couple sailed off into to the sunset back to the island for the honeymoon.
Antonio is shown to be somewhat self-sacrificing; giving up his happiness and possibly freedom for Rosella to be free. Antonio was known as a young prince who is adventurous and unafraid to follow his heart; he asks Rosella if they can run away together as his parents disapprove of her.