Continuity mistake: The seventh sword that Eustace had placed on top of the six swords is missing in the scene of the three lords waking up at the end. (01:33:17)
Continuity mistake: After the children are transported to Narnia, Edmund's hair is significantly shorter than it was while they were in England.
Continuity mistake: When Edmund is drinking water from a cup, he lifts it up to his mouth but in the next shot (from the side angle) it is lower down.
Continuity mistake: In this film, Prince Caspian speaks with an English accent. However, in the previous film "The Chronicles of Narnia: Prince Caspian", he spoke with a Mediterranean accent.
Answer: He's suppose to be the same age as in the novels, so about 16. "Voyage of the Dawn Treader" takes place 3 years after "Prince Caspian", so 2306 (Narnia year). He was born 2290 (NY). However, since Caspian is around Peter's age, they chose an older actor to play Caspian to match William Moseley's age.
Bishop73