When Lizzie is climbing up the hill to the overlook, her knees are wet before she kneels on the grass.
When Lizzie is reading the last letter, it says "Thanks for the book" twice, but it is only read once.
In one of Frankie's letters to his dad, the text of the letter does not correspond to the voiceover. Frankie says, "Ricky Munroe told me. Trust him to put his big feet right in it." but the letter reads, "Trust him to put his size threes right in it."