Continuity mistake: After Sebastian knocks over the bowl onto the chef's head, when Louis goes after Sebastian with the cleaver the style of the handle and the blade changes when Louis lifts the cleaver over his head and then chops the table. It happens again when the cleaver blade is rammed into the floor in front Sebastian, and in the next shot as Sebastian turns around the cleaver style has changed again. (00:54:10)Super Grover
Continuity mistake: When Ariel and Flounder are going into the shipwreck at the start, Ariel goes through the porthole and Flounder follows. In the frame where he gets stuck, his front fins are trapped firmly outside the porthole but in the next shot inside the boat, they appear inside instead of outside.
Continuity mistake: In the scene when Ariel saves Eric after the ship has exploded he has boots on yet when Ariel has brought him up onto shore they are off, they couldn't have fallen off since they in that time period men wore boots that have to be taken off to at least to the heal and Ariel is tying to save him so she wouldn't take the time to get them off, and leather tends to tighten up when thoroughly soaked so that is another factor to why they shouldn't have come off this also happens at the end of the film after Ursula has been killed.Disney-Freak
Continuity mistake: When Sebastian is arriving at the concert, he gets pulled upside down by his Goldfish. When he flips his shell back over and sits in it again, on his left side he has two legs sticking out... then as he starts moving one of the legs just disappears.