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.
Audio problem: When Eric and Ariel swim to each other, she says, "Eric, you've got to get away from here." He replies, "No, I won't leave you," but his lips don't move. (Regardless of the reason, still a mistake.)
Audio problem: In the Diamond Edition Blu-ray, near the end of "Part of your world." The shot of Ariel descending and Flounder's reaction shot are reversed, making Ariel's mouth out of sync with the song.
Audio problem: In the beginning, when Flounder and Ariel are exploring the sunken ship, the ceiling caves in on Flounder. He swims toward Ariel and yells her name but his mouth is closed.
Chosen answer: They are all throughout the film but the biggest one is when Eric is steering the ship to stab or skewer Ursula.
Disney-Freak