Continuity mistake: In the opening shot at the breakfast table, there is a large cereal box and a carton of milk on the right side of the table, in front of two salt-n-pepper shakers. But during the scene it continues to swap to an angle behind the two shakers - but now the cereal box and milk carton have vanished, so as not to block the view for this angled shot. (00:12:30)
Continuity mistake: When Sharkboy and Lavagirl burst into the classroom looking for Max, there is writing on the blackboard ("Science, Chapter Two") written in yellow chalk. Strangely, later in the scene the writing is now written in white chalk, and the handwriting of the text is noticeably different. Then, later it goes back to yellow! (00:16:45 - 00:17:40)
Continuity mistake: When Max is about to climb up the tower of ice to retrieve the Crystal heart, Sharkboy hands him his left glove. But in the shot of Sharkboy falling down the ice tower, both his gloves are back on! (00:59:25)
Continuity mistake: At the end, where Marissa has just defeated Mr. Electric, Linus runs out of the room and into the snow. It's not the actor but instead a double running out of the room. In the next shot, he pushes past Max to get out of the classroom again.
Continuity mistake: When Max throws his dream journal towards Linus in the classroom it falls on the floor by his desk, but in the next shot it has reappeared on the desk in front of Max! (00:16:40)
Continuity mistake: When Lavagirl sneezes on the bridge to the Ice Castle, she causes Sharkboy to fly across in the air and he ends up dangling from the side of the bridge. In this shot his back fin is completely gone. But instantly in the next shot it has reappeared again, fixed on his back. (00:49:30)
Continuity mistake: When Mr. Electricidad tells his daughter Marissa to not go to recess, as she replies, and the Max talks with her, her plaited ponytail continues to swap from laying on her left shoulder, to hanging down her back. (00:15:25)
Continuity mistake: When Lavagirl is spraying Mr. Electric with lava, the position of her arms continues to change, from which one is outstretched and changing from being outstretched, to at her sides. (00:27:40)
Continuity mistake: When Max finds the plate of burnt and eaten cookies, he picks up one with shark bites in it. When he picks it up again to show his mother, the bites are different. (00:09:55)
Suggested correction: He probably picked up a different cookie.
Continuity mistake: After Mr. Electricidad tells Max off for talking to his daughter Marissa, as Max walks back to his seat Marissa's arms goes from crossed at her chest, to uncrossed with her left hand supporting her head. (00:16:00)
Continuity mistake: At the end of the scene in the kitchen where Max finds the eaten cookies, as he is walking back upstairs the carton of milk on the counter suddenly disappears between shots. (00:10:10)
Continuity mistake: When Max goes downstairs and finds the plate of cookies and the carton of milk on the counter, the carton and the cookies on the plate keep moving and changing positions during the scene. (00:09:50)
Continuity mistake: When Sharkboy is feeding the sharks at the beginning, the third shark he feeds instantly disappears underwater between shots. (00:01:25)
Continuity mistake: When Lavagirl's hair is on fire due to her anger, Sharkboy splashes her hair to put it out. Between shots her wet hair instantly dries and becomes fluffy and neat. (00:57:30)
