Rooney Mara claimed that the swordfighting was filmed with the actors using wooden swords at full strength, and adding in the blades digitally.
Many natural scenes in the film were from Son Doong Cave, Phong Nha-Ke Bang National Park, and Ninh Bình in Vietnam. The captured scenes were then graphically edited into the film.
The screenplay for this film was featured in the 2013 Blacklist; a list of the "most liked" unmade scripts of the year.
Levi Miller won a drama award when he was five years old for playing Peter Pan. He loves the film Peter Pan (2003).
To find the right actor to play Peter, the filmmakers looked at thousands of kids in the UK, the United States, Canada, and Australia before finding Levi Miller.