Revealing mistake: When Harry brings Ron to see the mirror of Erised, the green side of the invisibility cloak is seen when they are running to the mirror, near the door they entered from. (01:33:55)
Continuity mistake: When Dudley falls into the water in the Python's exhibit, his clothes are completely soaked. Yet when Dudley yells and bangs on the glass, in the shot facing Petunia as she screams, it is quite apparent that Dudley's sweater/jumper is not entirely wet. The wet hair at the back of his head lies flat in the second shot as well. (00:07:15)
Audio problem: When Dudley is complaining about the number of birthday presents he got, his mouth doesn't match with what Dudley is yelling. His line is badly dubbed. (00:05:00)
Continuity mistake: After Seamus' disaster with the rum spell, the mail arrives. Ron catches his mail, then holds the Daily Prophet in his right hand and the letters in his left. Yet in the next close-up he holds the Daily Prophet in his left hand and the letters in his right. (00:54:05)
Continuity mistake: When Mr. Ollivander takes the first wand out of the box to give to Harry, the board, shelf, roses, etc., are visible behind him. When Harry takes the second wand to wave, just before the vase explodes, in the close-up the hanging red feathers, black roses and notes to the left of the roses all visibly differ to the previous shot of them. (00:25:50)
Continuity mistake: At the hut on the rock, after the camera pans sleeping Vernon and Petunia, there's an overhead shot of Harry and Dudley downstairs. In this shot the hanging light, its switch and cable are visible over the stairs. Note, the cable switch hangs down low, parallel to the droplight. However, when Vernon and Petunia are at the stairs, and she turns on the light, the cable and switch are now perpendicular to the droplight, raised higher up parallel to the wood above. Seen in following shots as well. (00:12:25)
Revealing mistake: In the flying letters scene, when the letters are coming through the chimney, if you look closely when Harry catches one you can see that the letters are all photocopied because the letter seal is not raised. (00:11:05)
Revealing mistake: During the Quidditch game, none of the players have shadows on the ground. (01:16:20)
Continuity mistake: In the Quidditch scene, when Madame Hooch steps onto the field she says, "Now I want a nice, clean game," and while she's looking up, her Hogwarts patch is on the left side of her robes. At the end of the Quidditch game when she says, "Gryffindor wins," her patch is on the right side of her robes. Interestingly, the shot of Madame Hooch is a flipped shot, yet it was pasted onto the scenic background, which is not flipped, but properly positioned. (01:23:00)
Continuity mistake: As the students board the Hogwarts Express to go home, the cuts on Harry's face, particularly near his eye, differ in severity during this scene depending on the camera angle in a given shot. (02:21:55)
Continuity mistake: In the scene where Harry, Ron and Hermione come with Filch to Hagrid to go into the dark forest, watch the lamp Hagrid sets down. Filch says something like "A sorry lot this, Hagrid". Then the shot cuts to Hagrid (look at the lamp) then to Filch again who says "Oh good god man, you're not still on about that bloody dragon, are you?" then to Hagrid again. The lamp changes position between these shots. (01:43:00)
Visible crew/equipment: The morning of Dudley's birthday, in the wide shot facing the kitchen when Harry walks in, to the right of the screen is a large framed photo of Dudley. The camera does not move as Harry walks toward the stove and reflected in that photo is a piece of studio equipment moving. (00:04:50)
Continuity mistake: In the scene where Harry figures out that Hagrid got his dragon egg from "Snape"(Quirrell), at the begining of the scene, Harry's cloak is buttoned and still is when he, Hermione, and Ron are running to Hagrid's hut. When he reaches Hagrid's hut, it is unbuttoned even though he never unbuttoned it himself. (01:46:50)
Continuity mistake: During Madame Hooch's flying lesson, in a close-up Ron says, "Up! Up!" to his broomstick. In the next wide shot of all the students, Ron stands next to Harry, who holds his broomstick, and just before it cuts to the next shot, Ron visibly grips his broomstick as it floats up to his hand, as well Seamus, who grabs hold of his too. Yet, in the next shot Seamus still says, "Up! Up!" and in Ron's next close-up, he still says, "Up!" to his broomstick still lying on the ground, which promptly smacks him in the head. (00:55:30)
Continuity mistake: Just after Flint leaps over the Weasley twin, in the next shot Flint tosses the ball forward - toward the hoop - with the school to his left (viewer's right) and Ravenclaw, Slytherine, Gryffindor and two staff (black/grey) towers behind him, to his right. However, in the next shot as the ball flies through the hoop (close-up), it is actually the hoop at the other side of the pitch - we see (in order) the Slytherine, Ravenclaw, Hufflepuff and Gryffindor towers to the left of the screen. (01:19:30)
Continuity mistake: When Harry Ron and Hermione run to see McGonagall, there is an hourglass, a large book and a candle all sitting directly on top of her desk. Their positions change, especially in the shot facing McGonagall, when she says, "I'm afraid Professor Dumbledore is not here...," not only is there is another small book next to the candle, the hourglass now sits on the large book. The long iron inkwell in the middle of the desk has also been turned around. (01:51:45)
Other mistake: In the Quidditch scene when Harry and the Slytherin seeker are chasing the snitch and are trying to bump each other off course you can see Hogwarts in the background. They pass Hogwarts twice while going the same direction. (01:22:05)
Continuity mistake: When Hedwig comes flying in delivering the broom, she drops it at an angle, but when Harry catches it it's completely horizontal. (01:11:50)
Audio problem: In the scene at the very end of the movie when Hermione and Harry are getting on the train, Hermione says, "Feels a bit strange going home, doesn't it?" Harry responds, "I'm not going home, not really." If you look closely, Harry says the words and his mouth moves. Then the camera changes angles and Harry mouths the same words once more, but no sound comes out. (02:23:15)
Continuity mistake: When Hermione shows Ron and Harry the Gryffindor Quidditch trophy, in the close-up of James Potter's name, Harry's reflection is visible on the badge. In the reflection, the points of his white shirt collar and a good portion of his tie are seen, whereas, in the shots facing Harry the collar points are tucked into his sweater and only the tie's knot is seen. (01:00:35)
