Continuity mistake: When James first talks to Sarah in the classroom, there is a white paper banner behind him that says "What are your favourite foods?" (The movie was shot in New Brunswick Canada and this is the correct spelling of "favourite" in Canada). However a few minutes later the banner is changed. It has been cut, there's a space in the banner and it is now spelled "favorite" in the American way.
Continuity mistake: In the first class, when James introduces himself, Johnny (the unapproachable boy) is writing slowly in a large notebook. When we see him first there are only a few lines, but a moment later the page is already half full. James tells him to stop, and when Johnny opens the book again the page is almost full. (00:07:20)
Continuity mistake: When the ferry with James lands the windshield wipers on his truck are positioned at an equal level. When we see the car going up the driveway to the school, one wiper is higher than the other, and when he arrives at the school they are at the same level again. (It goes without saying that it isn't raining and they aren't used.) (00:03:55)
Continuity mistake: When James visits Sarah's mother they sit down in a corner part of the living room with three windows. When the camera is on her, we see a dull, built-up area in the window with no greenery, but when we see both of them there are big bushes outside all three windows. A similar inconsistency occurs when Sarah returns home, but then the built-up area is behind the other window. (00:36:25 - 01:32:00)
Continuity mistake: When James comes jogging to the beach he notices Sarah who is sitting on a spit with her back to the land. He keeps throwing stones into the sea, and a moment later Sarah is standing behind him, throwing stones too. There was not enough time for her to make it back. (00:25:55)