Revealing mistake: During Fritz's fight with the giant anaconda in the swamp, James MacArthur's stunt double becomes apparent by virtue of a bald spot showing on the back of his head. (01:10:30)
Continuity mistake: The number of pirates assaulting the hillside keeps changing. There are hundreds of them, then fewer than thirty, then hundreds again. In many scenes, in fact, there are far more pirates than could possibly fit aboard their one small ship. (01:55:30)
Deliberate mistake: Fritz rescues the mud-trapped zebra and Roberta rides it across the island to the tree house, then again later in the race. Zebras, however, cannot be domesticated or ridden. To film these scenes, Disney & Co. painted a white horse with zebra stripes. (01:20:00 - 01:46:30)
Revealing mistake: In the scene where the logs are rolling down onto the pirates, you are given views of what's happening beneath the logs. Look closely at a pair of flailing feet. The pirate is wearing modern hiking boots.
Factual error: The pirates should have been crushed by the pile of rolling logs, but they just keep coming. No dead bodies, no blood, no guts, but hey, it's Disney.
Continuity mistake: In the beginning when it is raining down on everyone, you get a clear view of the mother's wet, mussed hair. In the next scene, however, it is perfectly dry and in place.
Revealing mistake: When Fritz is showing Roberta how to fire the rifle, several camera truck tire tracks can be seen on the beach behind them. (01:37:10)
Continuity mistake: When Francis lights one of his coconut bombs, you see the wick get smaller then bigger then smaller again.
Continuity mistake: While the two eldest boys are getting ready to sail around the island, Francis, the youngest boy, is playing with Rocky, the baby elephant. Francis is on Rocky's back, but in one shot, they are on the beach, near the water, and in the next shot, they are so far in the water that Rocky has to use his trunk as a snorkel.
