Continuity mistake: When JB dreams about singing "Master Exploder" in the small bar, he points at one guy in the audience and literally blows his mind. When he starts pointing you can not only see JB's face, but also how his elbow is in a slight angle. In the next shot the camera shows the guy JB is pointing at and his elbow is completely stretched. The views change several times and the angle of his elbow changes after every cut, until the guy's brain is finally blown out.
Continuity mistake: When the water wheel begins to roll, with Norrington and Will atop and then snatches up Jack, its blades (buckets on the outside rim) and two sides of the axle face a specific direction as it gains speed. Now compare the following two shots, as the water wheel rolls away from the camera: When the wheel rolls, just as Jack falls out, after hitting his head on the bar. Then later on the beach, as Elizabeth watches, just as the wheel rolls and falls over in the close-up, the wheel is actually rolling in the opposite direction - just note its blades. Also note the bizarre change of its axle's wide and narrow sides. (01:52:40 - 01:56:50)Super Grover
Continuity mistake: Right after Queen Latifah hits her head and is having a fantasy, LL Cool J is unbuttoning his shirt. The scene cuts to Queen Latifah and when it cuts back his shirt is buttoned up and his tie is tied properly. It cuts back to Queen Latifah and back to LL Cool J where his shirt is now once again completely unbuttoned. (00:14:00)AbercrombieCowboy
Continuity mistake: When Troy tells Chad that he wants to catch up on some homework and then heads to the audition, he's wearing jeans with thick decorative white stitching above his right pocket (viewer's left). However, when Troy raises his hand and volunteers to sing with Gabriella, he is wearing different jeans - the decorative stitching above the pocket is gone. (00:25:00 - 00:34:50)Super Grover
Continuity mistake: When Ashley moves in with her two friends she breaks their bathroom mirror with a hairdryer. Later on in the movie, in the scene where her two friends are giving her a pep talk about luck, we see the same bathroom mirror in the background, which is now perfectly fine. Right after that, Ashley goes into the bathroom and looks at herself in the mirror, which has suddenly gone back to being broken.
Continuity mistake: When Bullock is warning Reeves of the coming winter blizzard, she is looking through pictures that depicted her and her friends enjoying the snow. She then turns to the dog and asks "Remember that day? You were not happy". However it's revealed that both characters have the same dog, given to Bullock's boyfriend by Reeves, so when the snow happened in Reeves' time - 2004 - the dog was with him.