There is still no signs of any production for a Percy Jackson 3 despite the open ending 20th Century Fox gave to fans at the end of the second movie, The Sea of Monsters. Though there were rumors going around according to Hallels that a release date was set for October 2015, no confirmation from the studio was released about this or if there is a production green-lighted.

Though the first movie was successful, the second one was not which could be a big factor in pushing for the third installment’s production. It is also noted that there is no cast yet for the new characters to be introduced such as the di Angelo siblings (fans of the book will know who they are).
But time is not in the studio’s side, because if they are to retain Logan Lerman as the demigod Percy Jackson for future installments, his age will be way past the book’s character. On the third book, he is only 15 years old. The actor’s contract lasts up to the third movie. “If I was 30, sure I’d play Percy again.” He added though, “If we want to make a third one, I have to do it [because] I’m contractually obligated to three movies. I love those movies, they’re a lot of fun to make,” the 22-year-old shares with Hallels.
Alexandra Daddario tells Breathecast through an interview with the Associated Press that she is not convinced that the series is dead yet and is excited for any film that would follow. “I haven’t heard anything about [a third movie]. There could definitely be one, but I would be surprised. I would love to make one if they’d want me to.”
However, if one is to observe the order of the Percy Jackson movies, the third movie would be based on The Titan’s Curse.

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