Other mistake: After the storm, Grimsby helps Eric walk away from the beach while Ariel sings. Every time the shot back goes to those two they are on the same spot, though their legs move as if walking, giving the sense that they're on a treadmill.
Continuity mistake: When Scuttle watches human-Ariel wearing a sail for a dress, the rope, seaweed and plank in front changes for something else (looks like iron on wood or something).
Continuity mistake: After Scuttle takes the fork to his feathers his feathers are all puffy but then a few frames later they are suddenly back to normal without him doing anything.
Continuity mistake: When Scuttle arrives to the dock to tell Ariel about Ursula's plan, a bunch of flowers laying on the wooden planks behind appear/disappear randomly between shots.
Continuity mistake: When Eric's boat leaves with Ursula in, there are ribbons and a long piece of fabric decorating the side of the boat by the 2 portholes, which disappear in later shots.
Continuity mistake: When Ariel is about to discover she has feet, a thin strand of hair falls in between her breasts. A frame later, a wider strand is now laying on the right boob. This swaps back and forth several times.
Continuity mistake: After Ursula eats the shrimp, when the angle changes the rest of the shrimps in the shell become some sort of white beans.
Continuity mistake: When the storm breaks, the ship's look-out appears/ disappears randomly between shots.
Continuity mistake: When Ariel is peeping on the boat, Max licks her face and you can see that the rope next to the window disappears behind a beam. After Eric sees his statue, the rope is now really long and is laying on the deck, forming a big circle.
Continuity mistake: When the movie starts, the big lamp is lit, yet when Triton arrives to light it with his magic trident, it suddenly appears unlit.
Continuity mistake: When Scuttle peeps on the porthole and discovers Ursula, the design of the porthole changes style between the first and last shot.
Continuity mistake: When Ursula and Eric's boat sails away, people suddenly appear on the left side of the boat.
Continuity mistake: When Ariel refuses the eels' help, before they toss the face of the statue, she lowers her head and cries. A frame later the head is tilted to the right.
Continuity mistake: When the song 'Under the sea' begins, Ariel is sitting on a rock. The amount of purple flowers on the sides, specially on the right side, change drastically between shots: They appear, disappear, reappear, change flowers, then to algae.
Continuity mistake: When Ariel first sees the fireworks, they are coming from the boat, but when the angle changes and the boat has moved along, they are being fired from the same spot, though now it's set in the middle of the sea, which is absurd. Some animator screwed it badly.
Continuity mistake: When Sebastian escapes from the dip, the sauce has a white colour. When he throws the bowl over Louis' head it's changed to brown colour.
Continuity mistake: After the shipwreck, when Ariel sings, moss suddenly appears on the rock right below her hands.
Continuity mistake: Eric's ship sails swap from plain to striped when the storm breaks.
Continuity mistake: During the Sebastian and Louis scene in the kitchen, all the stuff on the tables around keeps changing (appearing, disappearing, reappearing) between shots, with no logic whatsoever.
Other mistake: In the last scene, where Ariel and Eric are sailing away in the boat, the rainbow in the background that Triton casts is backwards. It goes violet, indigo, blue, green, yellow, orange, and red. Very strange.
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