Continuity mistake: When King Triton destroys the stone statue of Prince Eric, you can clearly see that the statue's face explodes and breaks into pieces as well as the rest of the body. However, at the point a few minutes later when Ariel decides to meet the seawitch Ursula, she caresses the statue's face as a whole again.
Continuity mistake: In the beginning when Ariel is watching the sailors dance on the ship the dog comes over and licks her face, but she wipes off the wrong cheek.
Continuity mistake: When the wedding is taking place, the priest's cross turns upside down for one frame.
Continuity mistake: After Eric's wedding, Ariel arrives at the ship without shoes, then she receives her voice back and just before they try to kiss, she's wearing shoes.
Continuity mistake: When Grimsby is presenting the statue of Eric to the prince, one of the crew's shirts changes colour from white/black stripes to blue/black stripes.
Continuity mistake: When Ariel is in the Prince's guest bedroom, the covers suddenly appear over her.
Continuity mistake: When Eric first washes up on the beach and Ariel is singing to him/stroking his face, she has no fingernails. In the next scene she does.
Audio problem: When Ariel's sisters are singing in the beginning of the movie the yellowish sister's mouth doesn't move when she says her name.
Continuity mistake: When Sebastian is in Ariel's cavern with all her treasures, he accidentally gets his legs caught in a thimble. You can see it from the front, but when they show a shot from the back, it is gone. In the following shot from the front, it is back on again.
Continuity mistake: When Sebastian is hiding from the chef under a lettuce leaf in the kitchen, at first he is behind a bunch of stuff on the table. In the next shot, all the stuff is gone, and he's alone on the table.
Continuity mistake: When Flounder swims through an anchor at the start the anchor has round edges, but when the shark bursts in the anchor has flat edges.
Continuity mistake: When Eric first washes up on the beach and Ariel is singing to him, she looks to her left when she hears Max barking, but Max and Grim are actually coming from her right.
Continuity mistake: When Ariel is swimming back home from her treasure collecting trip at the sunken ship, she has her pink bag. Then the eels' eyes merge from watching her to Ursula's bubble globe thing Ariel doesn't have it anymore. Then when the scene switches back, she has it again.
Continuity mistake: In the first scene involving Ursula, the shrimp don't appear in her opened case until she reaches down for one.
Continuity mistake: When Ariel is at dinner with Eric and Grimsby, her fingernails are not painted when she picks up the fork, but are painted pink when she puts it down.
Continuity mistake: When Ariel and Eric kiss during the wedding ceremony, the wedding barque is thronged with people, but when Louis the cook chases Sebastian, the deck is suddenly bare of any and every person, including the happily married couple. Quite a flash-wedding.