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)
Continuity mistake: When Wood takes Harry out to see the Quidditch balls, he sets down the bat right against the box holding the balls. When Wood goes to open the box, you see the grass where the bat should be. And then he picks up the bat, which is not where it was originally placed. (01:01:30)
Revealing mistake: After being dropped by the troll in the girls' lavatory, Harry then scoots backwards on his backside and it is apparent that he is wearing knee pads under his pants. (01:11:40)
Continuity mistake: When Dudley pops up after Hagrid gives him a pig's tail, his face and hands are clean, even though he was just eating Harry's birthday cake with his hands. (00:16:40)
Continuity mistake: When Hagrid knocks down the door of the hut on the rock, in the close-up of the bottom door bolt and the piece of moulding, the bolt is clear of the latch on the moulding as they both fall. Yet, in the wide shot the bottom bolt is still within the latch on the moulding, as they both fall. (00:13:05)
Continuity mistake: In the overhead wide shot, before Madame Hooch says, "Good afternoon, class," as she approaches, each student stands directly behind the bristles of their broomsticks, yet in the next shot as the camera pans their feet, they stand between the bristles of their broom and the neighboring broom. (00:55:00)
Revealing mistake: At the start of the overhead shot as the troll's club smashes the cubicles, while Hermione lies on the ground, the top beams of all the cubicle walls and the front door of the second cubicle are all visibly pre-broken before the club slams into them. (01:10:15)
Continuity mistake: When Malfoy throws the Remembrall, he throws it back toward the crowd of students from which he came, yet Harry has to fly back across the courtyard toward the students after catching the Remembrall. (00:56:20)
Continuity mistake: At Hagrid's hut, when he places the dragon egg on the table, the book lies right next to the cup and saucer. Yet in the shots looking up from the edge of the table, directly in front of Hagrid and the egg/Norbert, the book and cup/saucer are far apart for these particular shots. (01:39:50)
Continuity mistake: When Hagrid is in Gringotts, in the shot facing Hagrid when he says, "Professor Dumbledore gave me this," his index and middle finger are on the side of the writing as he hands the letter to the Goblin Bank Teller, yet in the next two shots, Hagrid's thumb is on the side of the writing in front, as he hands the letter over. (00:22:45)
Continuity mistake: When trying to catch Neville's Remembrall, Harry flies straight for McGonagall's window. The window visible in the wide shot has a horizontal beam that crosses the center vertical beam, yet the window visible in the close-up just has the vertical beam. The number of stones at the sides differ as well. (00:58:30)
Revealing mistake: During Madame Hooch's flying lesson, as Ron tries to get his broomstick to float up to his hand, Ron moves his head towards his right to be in perfect alignment with the handle of his broomstick, as it flies up to whack him in the head. (00:55:40)
Audio problem: When the letters come flying out of the fireplace, Dudley yells, "Please, make it stop." If you look at his lips during this time, they're not moving. (00:11:25)
Continuity mistake: When Hermione is confronted with the troll in the lavatory she backs up and runs into the cubicle. In the overhead shot as she locks herself in, the pattern on the floor that is visible in front of the next cubicle is different than the previous and following shots. (01:10:10)
Continuity mistake: While Harry and Hagrid stand beside Hogwarts Express, in the shot looking up at Hagrid as he takes the album out of his pocket, his thumb is on the back cover as he begins to say, "This is for you," yet in the next shot of Harry taking the album, Hagrid's thumb is on the front cover. (02:22:05)
Continuity mistake: When Vernon says "I'm warning you now boy" between shots his coat changes position. (00:05:35)
Continuity mistake: On the Hogwarts Express, Hermione first watches as Ron tries to turn Scabbers yellow, she then joins them inside before she actually leaves and in these consecutive shots, her tie differs. (00:36:30)
Continuity mistake: Mr. Ollivander says, "I wondered when I'd be seeing you Mr. Potter," and as he climbs down the ladder Harry is standing at the middle of the desk, away from the corner. In the next shot as Mr. Ollivander searches for a wand case Harry stands at the corner of the desk. However, in the next shot Harry stands at the middle again. (00:25:30)
Continuity mistake: In the scene where Neville lost control of his broomstick during flying lessons, we see a shot of him going straight towards the castle wall (this is the first time he sees the wall). When you see him zooming towards the wall there are many windows. However, when the shot changes and Neville actually bumps into the wall with his broomstick, there are no windows seen. (00:56:35)
Continuity mistake: Malfoy holds Neville's Remembrall and as he begins to deride Neville, Hermione stands between Harry and Seamus. Yet in the next close-up Seamus is right next to Harry and then inches over a bit as Harry moves closer to Malfoy. (00:57:35)
