Portions of Circeland were filmed in the now-defunct Six Flags New Orleans, formerly known as Jazzland. The park was forced to close due to damage from Hurricane Katrina.
Although Clarisse is a new character in the movie, she was in the first book, "The Lightning Thief" Clarisse bullied Percy and attempted to push his head down the toilet.
While filming the yacht and lifeboat scenes, Alexandra Daddario learned she was prone to seasickness. Coincidentally, her character in the book becomes seasick on Queen Anne's Revenge.
Mr. D, or Dionysus, played by Stanley Tucci, makes his first appearance in the films after the character was written out of Percy Jackson & the Olympians: The Lightning Thief (2010).
Dionysus wears a shirt with the pattern of a leopard, his sacred animal.