A lot of the shots - especially the night time ones - used Miley Cyrus's double. Cyrus was still technically a minor at the time of filming so the number of hours she was able to work was strictly limited.
Liam Hemsworth won the part in the film after learning that he had lost the title role of Thor (2011) to his older brother, Chris Hemsworth. Liam had only just moved to the States from Australia at that stage and hadn't even gotten around to procuring an American agent.
The turtles proved difficult to work with as they only make their walk to the ocean at dusk. This effectively meant that the crew only had 15 minutes to shoot them before it got too dark, as the turtles didn't respond to artificial light, so it took 4 nights to get the required turtle shots.
Director Julie Anne Robinson and her cinematographer John Lindley deliberately used a lot of longshots and wide shots to give the film a feeling of a lot of space. This was to emphasize how alone and isolated a lot of the characters feel.
Tybee Island is a protected landscape. Permission had to be given every time someone had to walk on the dunes. The production found it easier to build their own which were rendered so perfectly and blended in so well with the real natural habitat that they were allowed to remain as part of the terrain after filming had been completed.