The Voyage of the Dawn Treader features a huge model of King Caspian's Dawn Treader ship and follows the adventures of Edmund, Lucy and Eustace, who are drawn into Narnia through a painting of a ship.
Along the way they meet everything from sea monsters and mermaids to slave-traders and dragons.
More than 80 people have been involved in the production, which runs until Saturday, September 27.
A 4pm matinee will be held on Sunday, with adult tickets the same price as children.