Continuity mistake: When Harry stabs the diary with the snake fang, the tip should be full of ink. However, there is no ink on the tip when it is on the floor.
Continuity mistake: When the Basilisk falls with his face upside down and dies, there is not much blood at his mouth and on his teeth. However, as Harry passes the Basilisk on his way to Ginny, the snake's mouth and teeth are now covered with a substantial amount of blood. (02:14:10)
Continuity mistake: While deriding Mr. Weasley in the book shop, Lucius Malfoy snidely holds Ginny's book up and as he says, "But judging by the state of this, I'd say not", in the side shot, he puts the book down and it's loud enough to be heard, yet in the next front shot he still holds it up and brings it down again. This is well before Lucius sneaks Tom's diary into the cauldron behind Ginny's book. (00:21:20)
Other mistake: Dutch DVD Only: After their crashlanding at Hogwarts, Harry and Ron are taken to Snape who tells them the Willow has been standing there "since before they were born". The Dutch translation reads "over a thousand years". It's a minor mistake on itself, but in Book 3 we learn how long the Willow has really been standing there and that's nowhere near "over a thousand years".
Continuity mistake: When the Hogwarts letters arrive at the burrow, Percy hands them out. He hands one to Fred and then passes one over Fred to give to George. But in the shot from behind the twins (looking at Harry and Ron), George receives another one. He is at the end of the table, so there is no one for him to pass it to because Arthur obviously didn't get one. (00:13:20)
Continuity mistake: When the bars on Harry's window are seen falling in the shot looking up, the windowsill is up on the left side and is visibly very crooked. Yet when the Weasley car backs up to Harry's window, the windowsill is perfectly fine again. (00:09:20)
Visible crew/equipment: After returning from the Chamber of Secrets, Ron and Harry are in Dumbledore's study when he says, "There is sufficient evidence to have you both expelled," and on the floor behind his chair is a broad bright white tape mark at the edge of the rug. (02:18:00)
Continuity mistake: In the first overhead shot of Dumbledore's study as he presumably starts to discipline Harry and Ron the corner of the rug below lies flat and evenly under Fawkes' perch. However when Dumbledore stands up to hand Ron the letter for Azkaban the rug differs greatly, though it has not been touched. (02:17:55)
Continuity mistake: In the Slytherine common room, Malfoy sits at the edge of the desk, as he speaks with Crabbe/Ron and Goyle/Harry and the items on the desk are visible around him. When Malfoy says, "It's been fifty years since the Chamber was opened..," he now sits at the left edge, the snake lamp stem is turned around, etc. (01:23:50)
Continuity mistake: While Ron and Harry are being reprimanded by Snape for the flying car incident, items on Snapes' desk change repeatedly depending on the camera angle. (00:29:35)
Continuity mistake: When Harry is in the Gryffindor common room with the diary, the candle in the lantern changes height dramatically. It is short in all shots, yet when the diary transports Harry and when it transports him back, the candle is much taller. (01:28:00)
Continuity mistake: When Harry chases Dobby down the stairs at the Dursleys, they stop in the hallway and there is a telephone on the table beside Harry. In the next close-up, the phone and cord's position differ and when Harry rushes past Dobby, the position differs again. (00:06:50)
Visible crew/equipment: When Hagrid and Harry leave Knockturn Alley, Hagrid's face is hidden in shadow, as it is really the body double behind Harry and we hear Hagrid's voice say, "You're a mess Harry. Skulking around Knockturn Alley? Dodgy place..." As Hagrid's (Robbie Coltrane) voice continues, "People will think you're up to no good," Dan Radcliffe reaches his white tape mark cueing him to turn and begin to say, "I was lost. I... Hang on. What were you doing down there then?" (Visible on DVD fullscreen.) (00:17:00)
Continuity mistake: When Harry enters the kitchen, the cake/pudding Petunia is fussing over is lopsided and shorter than the one shown in the close-up, when Dudley tries to pick at it. There are subtle differences in the look of the cake/pudding in subsequent shots of it too. (00:01:30)
Continuity mistake: As Ron and Harry stand in the girls' lavatory, Hermione gives them their glasses of Polyjuice potion. In the wide shot, Ron bends his left index finger to slip through the silver handle at the base of the glass and his right robe sleeve is way past his wrist as they proceed to put hair in the glasses. However in the close-up of Ron's hands, his index finger now goes through the handle the opposite way and a good amount of his right sweater sleeve shows under his robe too. Then when Hermione says, "Cheers," she holds the base of glass with the handle near her thumb, but no fingers go through it as she starts to drink the potion. Yet in her close-up she grips the glass completely differently. (01:19:40)
Continuity mistake: At the Weasleys, Ron takes his jacket off, picks up a biscuit with his right hand, then switches and holds the jacket in his right hand and the biscuit in his left. In the next shot, a close-up of Harry, Ron takes a bite of the biscuit which is in his right hand again and chews a mouthful, while holding the jacket in his left, yet in the next shot his jacket is in his right hand and he isn't chewing at all. He then takes a second mouthful of the biscuit in his right hand, but in the next shot as he looks down at his biscuit, only a small bite has been taken out of it. (00:11:05)
Revealing mistake: When Crabbe and Goyle are reaching for the cakes that Harry levitated, Ron and Harry are seen in the background, beside the statue, and though they are a bit out of focus you can clearly see that it is Rupert Grint's body double in each of the long shots. The shape of his face differs and his hair is very floppy. (01:19:00)
Continuity mistake: When Wood first spots the Slytherin quidditch team on their way to practice, you can see Ron and Hermione sitting on a bench in the background. You see Hermione put the book she is holding down beside her, and in the close-up, she puts it down again. (00:36:45)
Revealing mistake: At the Quidditch match, the goal posts are visible at both ends of the pitch in many shots, including the shortest ones. When rushing to Harry, Hermione shouts, "Finite Incantatem!" In the shot of Ron and Hermione's backs as they run towards Harry, the short goal post's base is visible on the left. It is completely different in this close-up than in any of the wide shots. (00:54:40 - 00:57:45)
Audio problem: When Harry enters the Chamber of Secrets and spots Ginny lying on the ground, he runs towards her. However, the sound of his footsteps don't match his actual steps. (02:04:40)
Answer: The joke goes like this, "A California business man, while in Japan for some business meetings and a few rounds of golf, arrived in Tokyo a day earlier than expected. Feeling lonely that evening, he employed the services of a beautiful young Japanese girl to be his companion for the evening. Although the Japanese girl spoke very little English and the businessman spoke no Japanese, their passion roared and in the heat of the moment she began yelling "Machigatta ana. Machigatta ana" Hearing this, the Californian believed he had pleased his female Japanese friend and soon afterwards went to sleep. The next day while playing golf with his Japanese business colleague, his Japanese partner holed his shot from 170 yards away. Wanting to impress his friend, the Californian began yelling, "Machigatta ana!" The Japanese business man turned to the Californian and with a confused look on his face asked, "What do you mean wrong hole?"