Revealing mistake: During the fight scene in the belly dancer's room, Bond spins the bald guy around to avoid being hit by a chair. When the bald guy gets hit in the back with the chair, you can see a large rectangle of padding under his jacket.
Continuity mistake: In the scene where Thunderbolt and Lightfoot are in the car with the crazy driver. The car goes over the embankment and as it flips you can see a wheel break off. A short time later they both drive off in the same car, with the wheel attached again.
Continuity mistake: When Barbara Windsor is getting undressed to prove that she is not a man, there is a red garment which is crumpled up on the bed behind her. When she finishes undressing the red garment is spread fully across the bed.
Continuity mistake: During the battle at the convent, one of the Cardinal's guards takes aim with his matchlock musket, is shot by Portos, and falls - along with his gun - into a hay wagon. But if you watch the falling scene closely, it is evident that only the man ends up in the hay; the gun should have fallen some place to the left of the wagon.
Other mistake: The Amazon's queen says she pierced Dharma's chest with her spear/lance but he's shown dying from a side wound.
Factual error: As the airship approaches Astragard it's headed due North; yet the distant clouds are backlit by the Sun. The Sun should be to the South.
Factual error: The film is set in the 1920's. When the policeman appears towards the end of the film on his helmet is a post-1952 helmet plate with the crown of Queen Elizabeth II.