Continuity mistake: Jack asks, "Where's dear William?" and Elizabeth runs over to the hatch that Will is trapped under. Tied to the hatch is a rope attached between two holes and lying on top is a piece of the broken mast and sail with more rope. In the wide shot of Elizabeth running towards the hatch and the following close-up, the ropes and twisted sail are either lying or tied differently on the hatch in both shots. This has nothing to do with the angle of the shot.
Revealing mistake: Either the first shot has a gratuitous view of the fort or the composite people neglected to add the fort in the second shot. Norrington says, "...this is the day that Capt. Jack Sparrow almost escaped. Take him away." The night shot that follows, shows the bridge archway, and beyond it the pier, Interceptor, the fort and its parapet. After Will breaks Jack out of prison, they approach the same archway and beyond it is the pier and Interceptor, but in this shot we don't see the fort and its parapet, nor the line that Jack slid down the day before. The camera angle is exactly the same.
Revealing mistake: When Jack holds the chain to Elizabeth's neck, and subsequently swings about, there are about ten links between the wrist shackles. When he tosses the links over the rope, before he slides down, there are at least fifteen attached links. Then at the blacksmith shop, when Jack sits at the anvil, there are eight links, and after he breaks it there are three links dangling from the right shackle and seven dangling from the left, totaling ten.
Revealing mistake: When the Black Pearl swings alongside the Interceptor for the battle, Elizabeth shouts, "Fire all!" The next shot is from behind the lit cannon which is aimed at the Pearl and the following shot faces the Interceptor's cannon, as it goes off. In the shot facing the Interceptor, the raw wood scaffolding type beams are perfectly visible at the entire lower part of the screen, where the painted planks (below the gun ports, above the bilges) of the hull should be. (This is ONLY visible on the video version.)
Continuity mistake: Aboard the Pearl, in the close-up of Elizabeth hiding the dinner knife in the napkin, the base of the decorative embossed silver knife handle (area of bolster, where the blade meets the handle) is flat all the way around. However, oddly enough, when she stabs Barbossa moments later, in the close-up of the knife protruding from Barbossa's chest there are two wide ridges circling the base - obviously a different knife.
Visible crew/equipment: When the Interceptor is totally blasted by the explosion of the gun powder deck and after Pintel says, "Any of you so much as thinks the word 'parley,' I'll have your guts for garters," just when Elizabeth goes under the rope, one can see a man with headphones on his head and a megaphone in his hand in the lower left corner of the screen - it looks like Gore Verbinski, the director. [This is only visible on the video version - someone sent me a screenshot as proof, but taken via a digital camera, so not really postable quality. Can anyone provide a better image?]
Revealing mistake: After Gillette locks the shackles on Jack's wrists, it is clear in Jack and Elizabeth's close-ups that the wider side of the shackles' distinctively shaped straight bar faces out at his wrists. However, when Jack is in the blacksmith shop, sitting at the anvil trying to break the links, the left shackle is actually around his wrist the opposite way. (This even occurs in other consecutive shots.)
Factual error: During Jack's sliding down the rope scene, it is very noticeable that each one of the English soldiers fire their weapons more than once, which is impossible for that time, knowing that repetition weapons weren't invented until the mid 1800's.
Continuity mistake: When Will delivers the sword to Governor Swann, watch the clock on the wall. While Will is waiting, the time is 09:45am. When Gov. Swann enters the room, the time is 09:40am.
Visible crew/equipment: At the blacksmith shop, Jack and Will start to duel and Jack asks, "But how's your footwork?" In the next close-up shot of their feet, the imprint of a modern, flat bottom trainer/sneaker sole can be seen on the dirt floor at the bottom right of the screen. It is not the imprint of a heel and sole of the time period. As a point of interest, on the video version of this film there are multiple imprints visible.
Visible crew/equipment: When the dock master tells Jack, "Hold up there you. It's a shilling...," seen in the background on the left of the screen is a thatched roof enclosure. An orange aluminum ladder is sitting under the thatch. Many of the crew's orange aluminum ladders of various heights can be seen on DVD 2.
Continuity mistake: When Jack sails toward Port Royal, he passes the skeletal remains of hanged pirates, to whom he pays a respectful bow. First, there are two wideshots of the skeletons, then in the close-up they are actually wearing more clothing, particularly the strapping middle guy, whose head position differs, and his straw hat is larger as well.
Visible crew/equipment: Jack is in one of the boats with Norrington and his men, at Isla de Muerta. Norrington looks through the telescope, saying that he doesn't care for the situation and in the wide shot, when Jack says, "Not if you're the one doing the ambushing," in the water, to the right of the boat, a crew member's green flipper can be seen coming up out of the water. The divers kept the boats steady while filming.
Visible crew/equipment: When Jack and Barbossa duel in the cave, Barbossa hits Jack in the face. Barbossa yells, "Aaaah," and Jack takes off running with his arms waving wildly in the air. In this shot, as Jack waves his arms, at the bottom right corner of the screen, the wood scaffolding that was built for the cave set can be seen near the rocks in the water. The cave set scaffolding can be seen being built on Disc 2 of the DVD.
Continuity mistake: When Barbossa takes the sword out of his own chest, he then stabs Jack with that sword, and he stabs Jack right under the strap and buckle. As Jack walks backwards, into the moonlight, the skeletal Jack appears and now he has the sword over the strap and buckle, in his chest. The length of the sword between the guard and his chest differs greatly, as does the amount of sword that protrudes from his back.
Visible crew/equipment: After Will tells Jack that he can get him out of prison, he lifts a wooden bench to use for leverage and says, "And the proper application of strength..." In the next close-up of the bench as it's positioned at the cell bars, a crewmember's fingers are gripping one of the bars at the bottom right corner of the screen. (This is ONLY visible on VHS.)
Visible crew/equipment: Before being marooned on the 'spit of land,' Elizabeth stands on the Pearl's gangplank. In her close-ups, with the island in the distance, the long 'metal pipe' guardrails are visible behind her in three shots where she is still wearing the dress. The pipes are also visible behind Johnny Depp (Jack) in three shots, including when Barbossa says, "That be the same little island we made you governor of..." In all other shots of the gangplank there are NO guardrails surrounding the actual gangplank while it's extended over the water. (This is ONLY visible on VHS, but can also be seen on DVD 2 and DVD 3 - 'The Lost Disc'.)
Continuity mistake: When Jack jumps down from the mast yard arm on the Jolly Mon to bail water, in the far wide shot, the mast pennant lies still, yet blows wildly in the previous shots and the bottom left of the sail is caught up on line from the rigging, but in the following shots, it's not. Also, in the wide shot he starts to walk to the middle of the boat, and he puts his arms out as he's starting to pass to the right of the mast. In the next close-up of Jack, he's passing the mast on the other side.
Visible crew/equipment: Just after Will cuts the lines from the Interceptor to the Dauntless, the Interceptor is shown leaving. The next shot is of the back wood plank between the ships falling away. On the deck of the Interceptor, behind the railing, on the right of the screen, is a crew member ducking down, so as not to be seen by the camera.