Revealing mistake: Will slides down the sail, aided by the knife. At the start of the next shot, when he grabs hold of the mast line, the cut in the sail runs the the bottom edge of the sail, yet, Will is actually seen falling from the top of this shot - way above the end of that knife cut. (01:36:10)
Super Grover
Continuity mistake: When Elizabeth enters the carriage, after her father rescues her from prison, the bottom of her dress is quite filthy. However, when she runs out of Beckett's office, it is much cleaner.
Super Grover Continuity mistake: Aboard the Pearl, when Jack goes in search of rum, he sees Bootstrap and places the lantern down with the metal clasp at the center - note the handle. However, when Bootstrap says, "I already told you Jack, time's up," the clasp is actually moved to the side - note the handle.
Super Grover Continuity mistake: When Elizabeth points the gun at Cutler Beckett, a certain amount of her hair is down, but more hair is pulled up in following shots.
Super Grover 
Continuity mistake: Aboard the Pearl, after Will orders the rum to be loaded, and Gibbs responds, "Aye, the rum too," the cloth round Gibbs's neck has the loop to his right, but in previous and following shots it's actually "tied" round his neck the opposite way, with the loop to his left. (02:00:00)
Super Grover Continuity mistake: When Elizabeth, Jack and Gibbs speak on deck about Beckett wanting the chest, the flask's black strap repeatedly jumps over and under the cloth round Gibb's neck.
Super Grover Continuity mistake: When Beckett says, "A marriage interrupted," he writes "Lord" as he signs the Letter of Marque, but when he places his seal, his handwriting differs. (00:29:40)
Super Grover 
Continuity mistake: After the Flying Dutchman's attack on the Pearl, when the Kraken attacks the Pearl, one of its tentacles comes through the captain's stateroom stern windows, which has considerable damage - notably the left window and part of the wall are completely gone. When Gibbs says, "Abandon ship or abandon hope," the stern windows are actually more intact - especially the left window/wall.
Super Grover Visible crew/equipment: When Jack opens the compass on the deck, two round lights are reflected on the lid. They are obviously stage lights, since from another point of view neither the sun nor any type of light is seen.
Sacha 
Plot hole: In a close-up, just as Jack is freed from the hole in the water wheel, we see the axle's circular wood frame with its spinning bars, above and behind him, as he runs the wheel. At the end of this close-up, Jack's happy facial expression gives way to a look of dread, as he supposedly sees an approaching metal bar about to make contact with his forehead. This is impossible, since all bars are spinning behind him. After a close-up of the actual bar, in the next shot as Jack's forehead makes contact, he stands further back and is now at the center of the circular wood frame, so as to be in perfect alignment with those spinning bars. (01:52:40)
Super Grover Continuity mistake: Throughout the film, Will's hair continually changes position between shots, such as hanging loose, then behind his ear, and back again, or vice versa; for example, when he holds Elizabeth's dress aboard the "bride spirit" ship.
Super Grover 
Continuity mistake: When Cutler Beckett shows Will the Letter of Marque, the seal beside King George's signature is seen. Later, while Elizabeth points the gun at Beckett, he places his own seal below, and the shape of King George's seal is entirely different now.
Super Grover Revealing mistake: The long bamboo pole lies directly at "Chief" Jack's back whilst he is bound by the rope. However, when Jack escapes and runs, in a few shots there is a distinct outline of an apparatus at his back - under the vest, with which the pole lies higher up, away from the actor's back.
Super Grover 
Continuity mistake: After the cage of bones falls into the water, Cotton reaches up out of the water to open the broken cage, but in the next shot he is still under the water, behind Marty. (00:40:45)
Super Grover 
Continuity mistake: In the scene where Will visits Elizabeth in jail, she is rubbing his chin in most of the shots but in one shot her hand is suddenly down and then it goes back up again in the next shot. (00:18:40)
Revealing mistake: The crow pecking on the floating coffin Jack is hiding in has a modern-day identification band on its leg.
raywest Continuity mistake: When Jack beheads the pirate and then when the pirate body searches for its head as Jack unlocks the chest, the plant debris appear and disappear in Jack's hair.
Super Grover Continuity mistake: In the row boat, on their way to Tia Dalma's, when Gibbs discusses the Kraken, the large tear at his shoulder is visible, as are other imperfections on the tattered vest. Later, the tear disappears and other things change as well.
Super Grover Revealing mistake: When the crew is first rowing up the tributary to Tia Dalma's shack while Gibbs is telling the story of Davy Jones, Ragetti (the eyeball pirate) is shifting his head back and forth, but part of the skin on his neck doesn't move with it; apparently it is some sort of prosthetic.
Audio problem: Before the Tortuga bar brawl the musicians are shown playing their instruments. When Elizabeth says, "I just wanted to have the pleasure of doing that myself," it is quiet in the bar, but the violinist is seen happily playing directly behind her and no sound is heard.
Super Grover 
Answer: There is a scene after the credits of "The Curse of the Black Pearl": the monkey got back to the cave and took a coin. That way he turned undead again.
Bjoern_Buller