Continuity mistake: In the shot of the horse jumping off the ferry, the ferry's name "Quinault Seattle WA" is seen on its side. Rachel looks down at the horse in the water from the same place it jumped, but the appearance of the ferry's name is now different, namely the position of the two words "Seattle" and "Quinault" are now flush with each other when they were not before. (00:55:40)
Continuity mistake: Naomi Watts' dark roots change length throughout the movie.
Visible crew/equipment: When Noah and Rachel get back home to Aiden and Noah picks him up you can see a crew member's silhouette in front of a window. (01:36:44)
Revealing mistake: When Rachel searches online for "Moesko Island," you can see in the address bar of the browser that she is really looking at local files (C:\WIN98\Desktop\search.com\... etc). (00:42:30)
Continuity mistake: When the woman is watching the film and trying to see the lighttower, she has blood in her nostrill even though she has not yet started to bleed.
Continuity mistake: In the first scene in Rachel's apartment Noah bites into an apple. First we hear him say 'ok' while he is still chewing but it doesn't sound as if there is something in his mouth, then he goes on talking after swallowing down everything, and finally we see him from behind, busily chewing again without having taken another bite. (00:29:30)
Continuity mistake: At Katie's wake Aidan approaches her picture with a condolence book in front. There's a pen lying on the book with its tip pointing towards the picture. When he puts down his flower the tip is pointing at him. (00:12:45)
Continuity mistake: The scene where Aidan is waiting for his mother in the classroom starts with a close-up of his hand drawing a sun. From the way the rays are arranged we can tell that it's not the same drawing that's used in the later shots. Similarly, the picture his mother takes out of the folder later is not the same she is looking at when the camera angle changes. Also the way she holds it is different. (00:07:20 - 00:09:05)
Factual error: The well in the video is situated on level ground. The Cabin under which it is now supposed to be has been constructed on inclined ground.
Continuity mistake: When Rachel first meets Richard Morgan during their conversation, Richard's jumper and collar are green in some shots, but blue in others; it's very noticeable as he opens the cupboard and cleans his shoes. (00:59:30 - 01:02:30)
Continuity mistake: When Rachel enters the reception at Shelter Mountain Inn the caretaker asks her to pick a card from a deck. She picks the nine of diamonds, but when she gives it back to the guy you get a blurred glimpse of the card, and it is a four of something. (That she finally agrees that the seven of spades is the right one is probably because she gets tired of the game.) (00:21:15)
Other mistake: The skull they used for the little girl in the well is obviously an adult's skull.
Other mistake: When Samara is falling down the well and we see the approaching water surface from her POV, there is a reflection of Anna looking down the well but no reflection of Samara.
Factual error: In the scene where Rachel is walking in the street looking at the photos she has just collected from the photo-shop, her hands (and the rest of her body) are moving in the natural way. In the shot at the photos taken from behind her you can see the ground moving underneath her but her hands are perfectly stable suggesting she is standing on a moving platform.
Continuity mistake: After breaking into the records room, Noah is looking at Samara's pictures or photo negatives, holding them up to the light, the shot of him show his fingers covering some of the first picture, but the next shot from his point of view the whole picture is visible and his fingers cannot be seen. (01:04:25)
Continuity mistake: In the scene where Rachel approaches the horse and the horse starts going crazy, you can see the ring at the end of the rope securing the horse break away from the trailor. In the next sequence when the horse is running around on the barge, the rope is broken with no ring.
Continuity mistake: When Noah is at the supermarket buying cigarettes, he pulls out of his pocket a bunch of junk such as coins, trash, and an old pack of cigarettes and dumps it on the counter. In the next shot of the counter, all the junk is gone except for a coin, and the old pack of cigarettes.
Continuity mistake: The knot of Aidan's tie is done in at least three different ways during Katie's wake: When he puts the flower down before Katie's picture, when he walks down the upstairs hallway, and when Rachel speaks to him in Katie's room. (00:12:35)
Continuity mistake: When Aidan and Noah are talking in the car, outside of Katie's house, Aidan is coloring on a blue lap tray. When Rachael comes to get him out of the car a couple of minutes later the lap tray is now green. (00:51:25 - 00:53:10)
Continuity mistake: On the way to Shelter Mountain Inn Rachel is seen driving along a lake. The water is to her right, and the forest to her left. A helicopter shot confirms that, but when we see the car from the front the forest is to her right. (00:20:45)
