Bethany Hamilton was involved in the film's editing process and suggested that the shark attack scene was too intense, and requested for it to be "toned down". She said that during the actual incident, everyone was calm.
Bethany Hamilton and some of her family members had cameos in the movie. In the church scene her parents are behind Dennis Quaid and Helen Hunt and her sister-in-law sings in the worship band. In Thailand while the mission crew are serving food, Bethany walks across the screen holding a large box.
Bethany Hamilton's father said that David Zelon, an executive at Mandalay Pictures, lobbied to reduce the movie's Christian elements so the film could appeal more to non-Christian audiences. This included such elements as having the words "Holy Bible" digitally erased off the cover of a Bible that Dennis Quaid reads from in the movie; and a scripture verse quoted by Carrie Underwood being edited so as not to indicate its Biblical origin. After strong objections from the Hamilton family, these edits were restored.
The far away surfing scenes are actually Bethany Hamilton because AnnaSophia Robb isn't the best surfer and Bethany wanted to be a part of the movie, Bethany is also seen when her character is helping with the recovery from the tsunami Bethany is seen carrying soccer balls in a box from the side so you can't see her lost arm.
FilmDistrict Pictures originally committed to a low-key release to 300 theaters. However, they were so impressed with the final product, they ramped up a full marketing campaign and release to over 2000 theaters.