Audio problem: When Bilbo and Frodo are reunited at Rivendell, Bilbo embraces Frodo and Bilbo's voice can be heard saying "Oh." But, his mouth is closed and could not have possibly said it.
Continuity mistake: When Gandalf and Saruman fight at Orthanc, Gandalf causes Saruman to slam backwards into the wall and then Saruman makes Gandalf spin horizontally in mid-air. In the next shot, when Gandalf falls, the wrap around his left hand is visible, yet, he does not wear it in the previous and following shots.
Continuity mistake: At Dwarrowdelf, as Gimli runs towards the Chamber of Mazarbul with Balin's Tomb, we see outside the doorway an assortment of body remains, armor and other objects. Then after hearing the approaching Orcs, Boromir looks out of the doorway, and we see to his left that the various body remains and armor are different. When Aragorn and Boromir close the doors to the room, outside we see the position and/or variety of body remains, armor and objects change again.
Continuity mistake: As Gimli weeps at Balin's Tomb, he says "Oh no. No." There is a wide shot, and this is the first shot of the skeleton and pail resting on the stone well. In this shot, the skeleton's feet and head, which are leaning to its left, are in different positions than in the second shot of it. In the second shot, Pippin backs up towards the well, and the skeleton, with its head leaning to its right is shown. Then in the third shot Pippin turns toward the well as Gandalf reads, "A shadow moves in the dark," the skeleton's head now leans to its left. In the fourth shot, as Pippin starts to touch the arrow, the skeleton's head is now leaning forward to its right.
Continuity mistake: While Bilbo stretches at his desk and calls out "Frodo, someone at the door" the words on the page in his book can be seen. The last line written is these four words "among the very wise." Yet in the next close-up shot of Bilbo writing again, the last line on the page is these five words: "counted among the very wise." They are different variations of the same page in Bilbo's book used in these two shots.
Continuity mistake: During the prologue, in the close-up shot of Isildur coming and kneeling at his father's side, we see he removes his own helmet and lays it down above Elendil's head. Elendil's own helmet is lying to the left of his head. In the wide shot from above, there is now a helmet above Elendil's head and a helmet between Elendil and Isildur. There is no helmet to the left of Elendil's head.
Continuity mistake: After the battle at Amon Hen, Frodo rescues Sam from drowning and pulls him into the boat. During their dialog in the boat, you can see that the boats' stern is pointed toward the bank of the river. There is one brief view of them from the riverbank where the side of the boat is facing the riverbank.
Audio problem: In two shots at the end of Frodo and Gandalf's conversation in Moria (before the Fellowship enters Balin's tomb), Gandalf's beard is moving as if he were talking, but he doesn't say anything.
Continuity mistake: At Bag End, Gandalf tosses the envelope with the Ring into the fire. He grips tongs tightly between his thumb and other fingers and reaches into the fire with his thumb facing his left side. In the close-up, the Ring is grasped on the same side as his thumb, with the excess Ring on the other side with his other fingers. Yet in the next shot, Gandalf lifts the Ring out of the fire and the Ring is grasped on the same side as his other fingers, with the excess Ring at the same side as his thumb. This has nothing to do with camera angles.
Revealing mistake: At Rivendell when Frodo puts the Ring on the stone table in the middle and then Gimili says his, "I'd rather die than see the Ring in the hands of an Elf" Gandalf stands up an makes a sort of "you're out- like an umpire" move at someone while they are all arguing, when the camera is on the people. When they go to the reflection on the Ring, Gandalf makes the movement again. Clearly it is the same shot again.
Revealing mistake: After fleeing from Boromir, Frodo is approached by Aragorn and Frodo passes a statue on a stone base and a stone pillar near stone steps. As Aragorn follows Frodo, in these shots, Aragorn's height and waist reach the same markings as Frodo when he went past these same objects.
Continuity mistake: In the opening shot of Bag End, as Bilbo says, "The Third Age of this world," we see the halls outside of Bilbo's study as Bilbo writes. There is a dresser with books on it, books lying near the coat tree, stacks of books and papers all over the floor and against the walls. Later, just before Bilbo says, "Frodo, someone at the door," and then when Bilbo searches for the Ring in the hall, in all three of these shots, the arrangement or even existence of quite a few of those books and papers is different. This has nothing to do with his search of the Ring.
Continuity mistake: When Gandalf says, "Mellon," the doors to Moria open and they all go in. Legolas soon picks up an arrow and says, "Goblins!" When he does so, we see the left long braid is loose at the end and coming undone. After Boromir shouts, "Legolas!" in the close-up we see the perfectly made long braid hanging down.
Continuity mistake: At the Council of Elrond, when Merry and Pippin run up and yell, "We're coming too. You'll have to send us home tied up in a sack to stop us!" Elrond's eye contact does not line up with the Hobbits, as they run past him towards Frodo. Then in the Hobbits' close-up, their height reaches just under Gandalf's and Legolas' shoulders, but in the wide shot the Hobbits are much, much, shorter.
Continuity mistake: When the Balrog's whip wraps around Gandalf's ankle and pulls him off the bridge in Moria, you can see that the surface of the bridge where he was standing is perfectly flat and smooth. We cut to Frodo screaming, then back to Gandalf, who is now hanging onto an easy-to-grip groove in the rock.
Continuity mistake: As Sam is getting into the boat, in Lorien, you see Boromir's body (not head) on the right of the screen and Aragorn's body (not head) to the left. All three including Sam, are wearing the cloaks they received in the scene before. While Sam gets into the boat, the voice-over you hear in these few shots is Celeborn, who is actually talking to Aragorn on shore. Then in the next shot of Aragorn talking to Celeborn, Aragorn isn't wearing his cloak, as he's receiving the knife gift from Celeborn. The next problem is, while Merry and Pippin talk about Lembas, Boromir is in the background without his cloak. In the next shot when Sam gets into the boat, in the background we see Boromir's body with the cloak on again. Next we see Aragorn still talking to Celeborn on shore, in the background we see Boromir and he's not wearing the cloak yet again. The shots were obviously put together out of sequence, and none are flashback.
Continuity mistake: After Boromir is hit with the second arrow, he falls to his knees. When he shoves his sword into the Uruk in the close-up, the silver clasp on Boromir's red shirt, at the center of his torso, is not clasped to the red loop on the opposite side (but it was in previous shots). However, in his extreme close-up, when he screams out, it is properly clasped like the rest on the red shirt, but in the very next shot it is not clasped yet again, and of course it is in following shots.
Continuity mistake: After spotting the Crebain from Dunland, the Fellowship try to hide. Just after Frodo and Aragorn hide under some boulders, there is an aerial shot of the area. Frodo, holding the green cloak, can be seen ducking behind the tall boulder on the left, even though he's shown already hiding in the previous shot.