Though the ship scenes are supposedly set on the Sun Princess, at least three different ships' exteriors are shown during the course of the movie. Herbie is shown being loaded on to the actual Sun Princess in the beginning, but later, aerial shots of the ship are actually of the Island or Pacific Princess (aka The Love Boat), which, whilst still a Princess ship, has a differently-shaped funnel. When Herbie is dispatched into the drink, the scene is set on an entirely different ship all together; you can see two orange funnels in the background, when in fact the Sun Princess has only one aft funnel with Princess' trademark Seawitch on it.
When Paco in the beginning looks at the film from the wallet, it's a negative strip, a standard orange-brown-sided negative and it's short and folded.
When he checks it at the end it has turned into a diapositive strip, long and unfolded.
And the plot emphasizes that only 1 film exists.
In the bullfight scene, inside the VW, the radio sometimes appears on the panel, sometimes a riveted plate appears in the place.
Just after the bullfight, Aunt Louise knocks the shoulder ornament off Captain Blythe's uniform as they get out of the car. By the time we see Captain Blythe outside the car, the ornament is back in place.
During the bullfight sequence, the colors of the decorations of Captain Blythe's uniform change from gold to silver and back again.
Captain Blythe says he is wearing a replica of the uniform Lord Nelson wore when he defeated the Spanish Armada. Although the Battle of Trafalgar Bay (1805) is chiefly remembered as a battle between the British and the French, the Spanish fleet was also involved. The combined French-Spanish fleet took a severe beating from the British Navy (which had very few casualties, though Nelson himself was mortally wounded by a French sniper), so technically Nelson did defeat a Spanish Armada.
When Herbie is pushed off the ship, his back license plate is gone. When we next see him floating in the water, it's back on.
When the Sun Princess is first seen sailing away to Rio from the pier, the scene is unmistakably a poor trick shot of a painted ship superimposed on top of some smaller ship.
After Shepard pushes Pacho onto the ground in the jungle, Quinn says "I don't like leaving that kid back there" and Shepard says "Don't worry about him! He's not going anywhere". If you're watching with closed captioning turned on, Shepard's name is displayed on the caption as Quinn speaks and then Quinn's name is displayed on the caption as Shepard speaks.
When Paco runs across the street, studio floodlights are reflected in the side of a VW Camper as it drives by.
During the end credits, children are singing the song about friends. At the very end, they incorrectly spell the word friend. - "F R E N D friend!" -