Freddie Highmore (age 13 when the feature was filmed) was originally set to star. His agent and mother also represents Daniel Radcliffe (age 16 during filming) which is how Daniel came on board; Freddie had to pull out because his grandmother became sick and he couldn't leave England to film in Australia.
To make sure he could deliver an authentic Australian accent for the film, Daniel Radcliffe started studying and practicing Australian accents six months prior to shooting.
Star Daniel Radcliffe says he had always planned to make another movie between the fourth and fifth "Harry Potter" films ['Harry Potter and the Goblet of Fire' (2005) and 'Harry Potter and the Order of the Phoenix' (2007)]. "I was sent a lot of scripts but none of them really appealed to me," said Radcliffe. "When I read 'December Boys' I loved it. It was a very simple story but I thought it was very beautiful. And my character Maps is very, very different to Harry, so I knew that would be a challenge for me. I've been playing Harry Potter for five years, so it was quite amazing to do something different. Hopefully people will see me in a new light after this."
Having movie star Daniel Radcliffe on board was a big plus for the other boys. Producer Richard Becker exclaimed: "The day Daniel arrived on set, his professionalism and focus really lifted the other boys, and he really helped to glue them together. He's a consummate performer and an extraordinary actor."
The film features the first on-screen kiss for Teresa Palmer. It was the last scene filmed on the production, which wrapped at 4am in the morning on Christmas Eve.