Goofs

During "Kiss the Girl", the fish swim up from a depth, but later, when Ariel and Eric fall out of the boat, they are shown in Ursula's ball standing in shallow water.

The trim on Ariel's wedding dress changes from green to pink, then back to green and stays that color for the rest of the scene. (This was corrected in the 2006 Platinum Edition release.)

When the crown falls off Triton's head it has eight prongs instead of usual five.

After Sebastian discovers Ariel's treasure cove and gets tangled up in her collection of human objects, he gets a thimble stuck on his claws. The thimble subsequently disappears and reappears between shots.

While in the castle of Prince Eric, Ariel lies down on a bed for the first time. Cut to Sebastian talking. Cut back to Ariel asleep on top of the covers. Next, Sebastian jumps on the bed, and Ariel is shown asleep under the covers.

At the end of the movie a rainbow is shown with the correct colors but with their order inverted.

During Kiss the Girl, Sebastian, Flounder and some of the fish cannot survive in fresh water as they are actually salt water fish.

In the 2013 Diamond Edition release, the two shots near the end of the "Part Of Your World" sequence were in the wrong order: Ariel should swim down before the reaction shot of Flounder. This was later corrected and a disc exchange program was created to replace the Blu-ray/DVD discs.

In the 2013 Diamond Edition release, the dissolve from "you really are a guppy" to Scuttle's first scene is cut short. This was later corrected and a disc exchange program was created to replace the Blu-ray/DVD discs.

Being entirely a "sea creature" (mermaid) with no societal links to the human world and the concept of nudity, and being surrounded only by other sea creatures, Ariel would have no reason to wear a human "bra", just like other depictions of adult mermaids who are nearly universally "topless". However, depicting her with bare breasts would be inappropriate for a children's film.

After Ariel becomes human the first time, Scuttle dresses her in a piece of sail cloth from the shipwreck. Moments later, Sebastian crawls into a pocket in the makeshift dress when there's no reason for a pocket to be sewn in a sail.

During the fireworks scene, the fireworks originate from the boat, but moments later, the boat has moved on but the fireworks are still erupting from the space where the boat had been.

When the Chef goes to poke Sebastian with the two-prong fork, the prongs trap Sebastian in between them and stick into the table. The holes that were supposed to be made by the fork were already there.

When Prince Eric and Max the dog are first seen, the ship's balustrade that Max's paws are resting on is clearly visible through his paws.

When Sebastian looks through a pair of glasses, his right claw disappears for an instant.

When the animals are sabotaging Eric's wedding to Vanessa, Scuttle tries to pull her seashell necklace away from her. The significance of the necklace should not be evident to him, as he wasn't there to see Ursula seal Ariel's voice inside it.

When Ariel is showing Flounder the book, it could never stay perfectly intact because it would be all wet and damaged from being underwater.

The fashion, design, and technology of Eric's kingdom suggest a setting no later than the mid 18th century. But Ariel's collection includes a portrait of Abraham Lincoln, who was born in 1809.

As Ariel and Eric swim toward each other right before the enormous Ursula rises above the sea they exchange dialogue: "Eric, you've got to get away from here." "No, I won't leave you." but their lips never move.

The pinnipeds in this film are either believed to be sea lions or fur seals, this film is set in the North Atlantic, more specifically in Europe's parts of the North Atlantic, neither living sea lions or fur seals are present in the North Atlantic ocean, they are found in either the Pacific, Arctic, Antarctic, or South Atlantic.

During the Under the Sea song, there is a part with a newt playing a flute, despite the film being set mainly in a marine setting, newts are freshwater animals, marine amphibians went extinct before the Carboniferous period.

Ariel signs Ursula's contract, with her name, showing that she knows how to write. However, when voiceless, she does not use this skill to write important information to Eric or anyone else who could help her.

The statue is too big to fit in the hole to Ariel's cavern, but it somehow makes it in.

Ariel could have used the trident to give herself legs .

Given that her father wields a trident, it seems highly unlikely that Ariel would have no idea what a fork is. At the very least, she would likely have believed it was a mini trident.

On Ariel's second day as a human, Eric takes her out on an adventure and makes plans to marry her, but doesn't give her an engagement ring.

When Ursula is explaining the bargain to Ariel, she says that she will make Ariel a potion to turn her into a human. However, neither she nor Ariel drink any sort of potion; once she has Ariel's voice as payment, Ursula simply waves her arms and makes the transformation happen.

When Ariel 1st encounters Max on Eric's ship, he licks her right cheek. When Eric calls Max over, Ariel turns to where she can see them and rubs her left cheek.

The song "Under the Sea" promotes the benefit of sea life. But a sea-dweller would understand that "under the sea" refers to the sand and rock of the sea bed. Sebastian should have said "inside the sea". Clearly the lyrics were written by a landlubber.

Ariel tells Scuttle she's never seen a human this close before as if it was her first time. In The Little Mermaid (1992) series, she has seen dozens of humans up close prior to the events of this movie.

When Flounder is trying to come up with an excuse not to explore a shipwreck, he says it looks damp. It's underwater, so of course it's damp.