Continuity mistake: After Pongo spots Anita and Perdita walking towards the park, Pongo moves the time forward on the clock and he leaves the dial's hinged bezel open as he rushes to the door and barks, but when Roger checks the time on the clock the bezel is closed. (00:06:20)
Continuity mistake: In the cabin when they are coming up with the idea to swap places, Susan has on white sneakers in the beginning of the scene when she is on the bed, and Sharon has on the black Mary Janes. Later in the scene, with no time to change shoes, Susan is seen walking around the cabin wearing the black Mary Janes.
Continuity mistake: When the two men are carrying water up to their new cave home (via a home made elevator), one of the men is holding two buckets of water. In the shot where you can see the sea behind them, this man hands the second man a bucket of water, which he takes. In the very next shot, from inside the cave, the first man has both buckets and again hands the other man the bucket of water. (00:48:35)
Continuity mistake: The police that come to the aid of the professor are driving an older Ford when they approach than when they arrive to help. The car is a newer model in the later scene.
Continuity mistake: When Sylvester sees a mouse, he chases the rodent and pulls the bulldog along with him. The bulldog grabs a small tree out of the ground and holds it in his hand, but when they go past the "Stop" sign, the tree has gone.
Continuity mistake: When Sylvester has caught all of Speedy's friends, he puts them in the bottle and he is holding the flute in his hand. But when see Sylvester a little later on, the flute has gone, and after Speedy has rescued one of his friends, Sylvester has the flute again.
Continuity mistake: When Sylvester sees the Daily Bugle newspaper, the front cover headline reads "Police Hunt The Cat." You can see the words THE CAT have nothing around them, but when we see a close-up of the newspaper in the next shot, inverted commas have suddenly appeared.
Continuity mistake: When the Coyote tests his dart bomb, he lights it with a match in his left hand. But when he throws the dart bomb in the next shot, the match that was in his hand has gone.