After The Chronicles of Narnia: Prince Caspian (2008) didn't fare too well at the box office, the Walt Disney Company decided for budgetary and logistical reasons not to co-produce and co-finance this or any of the following chapters of the Narnia series.
When Susan writes from America, a picture of the Pevensies rests on the table before her. This is a candid behind-the-scenes shot of the four actors from The Chronicles of Narnia: Prince Caspian (2008).
The drawings of the characters during the end credits are the same drawings that appeared in the book. This is a tribute to Pauline Baynes, the series' illustrator, who passed away on August 2, 2008 at the age of 85.
In the main cabin of the Dawn Treader with the map of Narnia there are also paintings of places in Narnia on the walls of the cabin. Tashbaan, the capital of Calormen and a city visited in the Narnia book 'The Horse and His Boy,' is frequently shown.
In a short cameo, Nathaniel Parker plays the father of Ben Barnes's character, Caspian X. Ironically, Ben Barnes had previously played the younger version of Nathaniel Parker's character in the film Stardust (2007).
The first trailer was released online at midnight EST on June 16, 2010, and theatrically on June 18, 2010, attached to Toy Story 3 (2010). On screens where Toy Story was shown in 3D, the Dawn Treader trailer was also 3D.
In the book the islands with the water that can transform anything into gold and the enchanted golden treasure that Eustace stumbles upon are two separate locations. It was a deliberate choice by the filmmakers to merge the two islands into one destination for running time and budgetary concerns. Interestingly the two magical sites are both tests of greed.
The original intention was that Miraz would briefly reprise his role as a hallucination triggered by the Green Mist. This would be the realization of Caspian's worst fear as his uncle would taunt him much like the White Witch appears to intimidate Edmund so that he would feel weakened. It was decided late into production they should switch the character and Caspian's father would be the apparition. The filmmakers hesitated because Caspian's father was a completely unknown face that could render the audience confused. They finally persevered with their second choice and went on to substitute Miraz with his brother, since they decided that the ultimate fear of Caspian was that he could never live up to his father's reputation as a King. Consequently, the manifestation of the Green Mist to influence Caspian resulted in being his father and not his uncle.
When Michael Apted signed on to direct in June 2007, filming was set to begin in January 2008 for a release date of May 1, 2009. Shooting would have begun in Malta and then moved to Prague and Iceland. A few months later, the Walt Disney Company announced, "In consideration of the challenging schedules for (its) young actors," it was delaying the release date to May 7, 2010, and filming was moved to October 2008. The shoot got rescheduled to Playas de Rosarito, Baja California, Mexico, where two-thirds of the film would be shot at the water tank that was used for Titanic (1997) and Master and Commander: The Far Side of the World (2003). Filming was also scheduled for Australia. Disney and Walden eventually grew concerned over Mexico's safety, and Australian officials at Warner Roadshow Studios in Queensland offered to become the project's base for the whole shoot.
The trivia item below may give away important plot points.
At the end of the film, we hear Eustace's mother announce that Jill Pole has come by for a visit. Jill becomes Eustace's companion on his two subsequent adventures in Narnia in the books 'The Silver Chair' and 'The Last Battle'. However this is a change to the books as Eustace doesn't meet Jill until the beginning of The Silver Chair while they are at boarding school.