Continuity mistake: Towards the end of the film we see Tom Hanks remove the rug with a moon on it to reveal a trap-door to what could be the final resting place of the Holy Grail. When the rug is lifted the Fleur-de-lis handle of the trap door is visible, but when we cut to a close up so Tom can lift it, it is almost completely obscured by dust and debris which he has to remove with his fingers.
Continuity mistake: When Teabing rolls the Cryptex to Langdon near the end of the movie, in one shot we see that the Cryptex rolls to a stop about 6 inches from Langdon's knee, but when the shot changes to an overhead view we see the Cryptex is now suddenly at least 2 feet from Langdon. Then the shot changes again and its now more like a foot from him.
Factual error: In the Louvre, Sophie puts the GPS receiver in a bar of soap and tosses it out the window onto a passing truck. Problem is, the bathrooms in that part of the Louvre don't have windows, or bars of soap (they have liquid soap dispensers).
Continuity mistake: When Robert, Sophie, Leigh, Remy and Silas are racing for Leigh's airplane, their vehicle's front windshield is hit by a branch and cracks. The large, branched crack is seen in another shot. But later shots of the vehicle on the way to the plane show no crack in the windshield.
Factual error: One of the main features of the Chapter room in Westminster Abby is the tiled floor - the tiles are red, small and octagonal, and hand painted. In the movie, they're big, plain bricks.
Factual error: The film features characters going through 3 doors in the Temple which are always locked. The first is the one Sophie and Robert leave the church by, the second is the one they leave Temple itself by and run onto Fleet Street - this one is shut in the film, but it's always locked in that case. Finally, the car leaves Temple onto Fleet Street using a door that is always, always locked.
Continuity mistake: When Vernet slams the door of the armored car, we see the brass bullet casing deformed, flattened on one side. We next see the bullet casing (must be same one since Vernet has not yet fired the gun again) on some flat surface with no apparent damage. If the deformed side had been facing away from the camera, the casing would have been lying at an angle because when the door crushed in the side, it was almost half way in. No way can this be the same casing.
Continuity mistake: When they are in Temple Church and Teabing is trying to force Sophie to open the cryptex, Langdon asks to try and says something like "But let me have a moment". In this shot, his left hand is raised, and is next to his face, but when the angle changes to show him from the front, his hand is suddenly down by his side.
Continuity mistake: When Robert and Sophie first arrive at Leigh Teabing's and sit at the table in the kitchen there are only dishes and things for serving tea on the table. In the scene after we see Silas reckless driving towards Chateau Villet, the shot pans around so that we see Langdon now eating from a plate in front of him and a bowl of fruit is now on the table. As Teabring is saying, "So Constantine may have been a lifelong pagan...", we see a shot of the table and suddenly the full bowl of fruit has disappeared.
Factual error: The temple church is very light, bright, and airy - especially on a sunny day like it was in the movie, it would have been very bright on the inside, not dark and dreary at all.
Continuity mistake: When Tautou is speaking to claustrophobic Hanks in the back of the armored truck, Hanks is frowning; but when the angle changes to his profile, he's smiling.
Continuity mistake: When Andre takes the cryptex from Sophie and Robert at the back of armoured car, and gets knocked to the ground, the position of the door changes. When Sophie comes out of the back the door is shown in the open position. When the shot changes to a frontal shot of Sophie running to the front, before Andre shoots at her, the door is now closed and apparently locked. We know it is locked because as they drive away the door does not open. (00:53:45)
Continuity mistake: After Vernet shoots over Robert's and Sophie's heads in the back of the armored car, the bullet casing lands on the floor. Robert kicks it with his shoe until it lands in a crevice of the door way but it is not next to anything, nothing on either side of it in the crevice. When Vernet tries to slam the door shut, the casing is now right up next to the other door which is shown as the camera pans straight down the edge of the closed door until it shows the bullet casing be smashed by the door Vernet is trying to close. (00:52:20 - 00:53:10)
Visible crew/equipment: Once Robert, Sophie and Teabing first arrive in London there is a shot where they are exiting a car after leaving the airport. As the car pulls up you can see the reflection of the camera in the front window.
Character mistake: During the meeting between Langdon, Sophie and Sir Teabing, Teabing refers to Scatoma as "the mind seeing what it wants to see." Scatoma refers to a partial loss of vision. He probably meant to use Pareidolia, which refers to seeing patterns that are not really there.
Continuity mistake: When Langdon is reading the papyrus text, it reads: "The Holy Grail 'neath ancient Roslin waits / The blade and chalice guarding are her gates / Adorned in master's loving art she lies / she rests at last beneath starry skies". But when Langdon runs to the Louvre to find her true location at the very end of the film, the voiceover switches the 2nd and 3rd line, so the rhyming pattern is ABAB rather than AABB. (01:55:50 - 02:14:30)