Continuity mistake: When Harry and Ron rush into the bathroom after the troll to rescue Hermione, they push open the closed doors, but wouldn't they be open from when the troll went in there moments before? The doors can't have closed after the troll as when Harry and Ron push open the door, it stays open. (01:09:55)
Continuity mistake: When we see Ron and Harry running into the transfiguration class, Malfoy and Crabbe can be seen working. When it shows a close-up of Malfoy, both Malfoy and Crabbe have changed body position. (00:48:30)
Continuity mistake: When Harry walks into Gringott's for the first time, if you look at the pattern on the floor he jumps forward about 5ft instantly. (00:21:10)
Continuity mistake: On the train, when Ron introduces Harry to Scabbers there are two Jelly Slugs lying on Ron's leg - one red-green and one yellowish-brown, but when Ron casts the spell on Scabbers both Jelly Slugs are red-green, and then it switches back again. (00:36:40)
Continuity mistake: When Dudley sits up when Hagrid knocks on the door, he is sat up. Camera cuts and he is sitting up again. (00:12:20)
Continuity mistake: When Hedwig delivers the Nimbus 2000, as Harry catches it, the curve of the Nimbus' handle, the packaging and the way he grasps it all differ in the close-up and following shot. Then when Ron says, "Let's open it," he moves his goblet and plate to his left towards Hermione's goblet, yet in the next overhead shot his goblet is still on his right. (01:14:50)
Continuity mistake: During the scene with the troll, Hermione crawls over to where the sinks are and if you look at the floor you will see that there are only a few wet spots. In the very next shot, however, the whole floor is soaked (this occurs before the troll breaks all the sinks). (01:10:40)
Continuity mistake: After Harry opens the package with the invisibility cloak, he stands near the red chair and when he says, "I don't know, some kind of cloak," the cards on the back board are visible. As Ron says, "Well let's see then. Put it on," he holds a Bertie Botts box in his left hand and has his right hand in the box. Next shot facing Harry, Ron visibly holds the box with his right hand and the positions of the pillow, cushion, envelope and letter differ on the red chair. As the next shot opens facing Ron, he holds the box in his left hand and his right hand is in the box. Then in the next shot facing Harry again, the bottom card on the back board is gone. (01:27:50)
Continuity mistake: When we first see Hermione on the train, her tie is crooked. When she sits down, as Ron is about to change Scabbers yellow, her tie is straight and it remains that way while she is seated. When she leaves and turns around to tell Ron about the dirt on his nose, it is crooked again. (00:36:05)
Continuity mistake: When Harry receives his letter from Hogwarts, he opens it and it looks like one letter standard size. When the shot changes, it looks like a card (but we saw Harry unfold it). And when they are in London, right before they enter The Leaky Cauldron, it's standard size again but now there is more then one letter. Notice the folded left hand corner. (00:15:50 - 00:18:35)
Continuity mistake: When Harry, Ron and Hermione go to the third floor corridor for the first time, they all run into the corridor with Fluffy in and close the door. In the next shot, Ron walks through the door again and closes it again. (00:59:40)
Continuity mistake: When told to relax in the Devil's Snare, Ron's hands keep changing positions instantly. (01:52:00)
Continuity mistake: When Quirrel collapses in the great hall on Halloween, his feet are quite far apart. Camera cuts to everyone rushing for the door, and Quirrel's feet are practically touching. (01:05:30)
Continuity mistake: When Harry is telling the others that Snape gave Hagrid the dragon's egg, there is a group of older people walking towards them. They start to pass Harry, the camera changes angle and they are just starting to pass Harry again. (01:47:50)
Continuity mistake: In Harry's first Quidditch match, Gryffindor scores the first goal, then we see the commentator announce the goal and change Gryffindor's score to ten - making a goal worth ten points. Soon after, Gryffindor score again. We then see Slytherin score a goal, then another. They then score a third goal, and the commentator changes the score to 20 all, but it should be 20/30. (01:17:40)
Continuity mistake: When Hagrid goes to leave, the door has a gap visible at the top where you can see the rain. When Hagrid grabs hold of the top of the door the gap has vanished. (00:17:20)
Continuity mistake: When Fluffy drools on Ron, the amount of drool changes drastically. (01:51:30)
Continuity mistake: The amount of shirt that is untucked on Ron just after their exams is constantly changing from a lot to a little. (01:46:20)
Continuity mistake: When Neville first takes off during the 1st flying lesson, Ron covers his face with his right hand. When the shot changes, his hand is no longer over his face. (00:54:20)
Continuity mistake: On his first night in the castle, Harry is sat on a window ledge with Hedwig. In this shot, his feet go from resting on their sides and crossed at the ankles to flat and uncrossed. (00:48:50)
