Keep Circulating the Tapes: When Lewis was checking the book over for publication in America, he made several changes, mostly in the Isle of Dreams sequence (the original British had the island entirely disappear; in the revised version it was stated to still exist). In 1994, when a new publishing company took over, they used the British text in the American printings, so the original American text is now getting hard to find.
An unusual, possibly coincidental example — Nathaniel Parker makes a brief appearance as the "ghost" of Prince Caspian's father. Previously in Stardust Ben Barnes, who plays Caspian, and Nathaniel Parker had played different-aged versions of the same character. Furthermore this would make it the second movie where Nathaniel Parker's son marries a star.
Advertised Extra: Trailers made it seem as though Peter, Susan and Jadis played significant roles in the film - despite Susan only appearing in two short scenes, Peter in one and Jadis only as an apparition. Tilda Swinton likewise said she was surprised that she was in the trailer, claiming she had only been on set for "about twenty minutes".
Bad Export for You: International DVD releases did not use the closing credits song from their country. Instead, the American one (“There’s A Place For Us” by Carrie Underwood) was used in the film itself and a music video for their respective song was included as an extra. Some Blu-Ray releases included a “End Title Songs from Around the World” feature with all of the international music videos.
Channel Hop: Although Walden Media was still producing the film, Disney dropped the franchise after the second one. And this was distributed by 20th Century Fox instead. Ironically, Disney's purchase of 20th Century Fox meant they inherited the distribution rights to the film anyways.
Franchise Killer: Though its overall gross was solid (around 400 million on a 155-million-dollar budget), three-quarters of that came from overseas, and things were clearly in heavy decline from Prince Caspian and The Lion, The Witch, and the Wardrobe (141 million and 291 million domestically). That, combined with a generally poorer critical reception, caused the production team to consider skipping ahead to The Magician's Nephew, before ultimately shelving the project altogether, leaving the franchise ended at three films out of seven books.
In Memoriam: A Special Thanks credit for Pauline Baynes, who illustrated The Chronicles of Narnia books and died from a heart disease in August 2008, and a proper in-credit tribute for Peter Apted, relative of director Michael Apted, who passed away in January 2010.
Missing Trailer Scene: The trailer had a shot of Peter and Susan in Narnian clothes, giving the impression they returned to Narnia in this movie.
The Other Darrin: Simon Pegg took over the voice of Reepicheep from Eddie Izzard. Justified because Reepicheep is older, which could have made his voice change.
Reality Subtext: The film adds an Affirmative Action Girl Gael for Lucy to serve as a Cool Big Sis for. Arabella Morton was the same age (ten years old) as Georgie Henley had been when she starred in the first film.
Troubled Production: Shooting was to happen in Prague, Malta and Iceland - but then was moved to Mexico. Shortly after, producers worried about Mexico's safety and moved everything to Australia. During this time, Disney chose to drop the film and it had to be picked up by Fox.
Originally the green mist would manifest itself as Miraz for Caspian, and his fear would be ending up as a tyrant like him. Later in production they changed it to his father instead.
Due to the episodic nature of the book, filmmakers considered combining it with The Silver Chair. Previously it was almost combined with Prince Caspian.
Initial plans for the green mist were to have it part of a plan by the Lady of the Green Kirtle. The actual cause of it is left open in the film.
Word of God: The green mist is caused by the Lady of the Green Kirtle, foreshadowing her role in the next story.
Word of St. Paul: Lilliandil, the name of Ramandu’s daughter was coined for the film by Douglas Gresham, C. S. Lewis’ stepson and one of the film’s producers.
