- Singapore didn't exist at that time, it was founded in 1819. Before, it was a tiny fishing village called Temasek, though the name "Singapura"—"city of the lions"—was first given in the fourteenth century, and its inhabitants were Malay, not Chinese. Singapore was an island of crime, so much so that it was called "Sin Galore" but most of it came from vice, not piracy.
- Gibbs has a Teddy Bear at the end. The incident with Theodore Roosevelt and his bear took place in November 1902. The political cartoons of Clifford Berryman which were inspired by the incident started appearing that month. The toy bears inspired by the cartoon were introduced, simultaneously but independently, by Morris Michtom and Richard Steiff in 1903. Although it is possible that it was an improvised toy, resembled teddy bear.
- In the beginning of the tea drinking scene with William, Lord Beckett adds a sugar cube into his tea. The first sugar cubes were invented in the Czech town of Dacice during 1840s.
- There is no record of any pirate communes working together as "Pirate Lords", to further elect their King. The real-life pirates only once gathered as something distantly resembling the Brethren Court, although it happened only once and was formally referred to as "Brethren of the Coast". The term "popular vote" used by Gibbs was used at the modern time of real-world democracy, which could not occur among traitorous pirates.
- Similarly, the Pirate Code was never a unified book of strict laws, which was lampshaded by Barbossa in the first film as "guidelines". Each pirate ship had their own Pirate Code depending on the captain of the ship, it usually consisted only of one page, it was not a huge Doorstopper shown in the movie.
- The British fleet seen in the film consists of some ten three-decked ships of the line. In 1720 the Royal Navy only had six such ships in commission world-wide.
- All the British Men of War in the film are painted in the "Nelson Checker" (black and yellow bands with black gun-ports). However this pattern was not common until 1805 when used by Admiral Nelson.
- All the gallows have a style of the New Drop trap door not used until 1813.
- When Beckett sets the Dutchman to give no quarter in the maelstrom battle, he orders his officer to make semaphore signals to the other ship. This is done by an officer holding two flags in different positions, the modern way. However, the British Navy in the 18th century did this by hoisting sets of special flags on the masts of the ships, not by setting an officer on deck.
- Directly after the battle between the Black Pearl and the Flying Dutchman near the end of the film, Barbossa says "Belay that, or we'll be a sitting duck!" in response to Jack's command. but the phrase "sitting duck" was not introduced until the early 1900s.
- When Pintel refers to the Kraken as a fish, Ragetti tells him it's actually a cephalopod, a term that was first coined in the 1820's.
- Sao Feng's navigational charts show that Juan Ponce de León discovered the fountain in 1523, but de León died in 1521, while the expedition for the Fountain of Youth started in 1513. Possibly it was just a misprint when the number "2" replaced the correct number "1".
Anachronism Stew / Pirates of the Caribbean: At World's End