In the movie, Carlotta is Prince Eric's maid and one of his most loyal friends. When Eric brings Ariel into the palace, Carlotta gives Ariel a bath and has her dress washed for her. After Ariel is done taking a bath, Carlotta dresses her up all nicely and takes her to the dinner room to where she will eat with Eric and Grimsby. When Ariel takes Grimsby's pipe and blows its contents in Grimsby's face, both Eric and Carlotta laugh about it, and Carlotta tells Eric that that's the first time she's seen him smile in weeks. Grimsby then asks Carlotta what's for dinner to which Carlotta tells him that he's going to love it because the Chef has been making them stuffed crab. They then hear a noise from the kitchen to which Carlotta decides to go and see what Chef Louis is up to. When she reaches the kitchen Carlotta finds Chef Louis throwing stuff around and making a mess and she asks him what he's doing to which Chef Louis apologizes to her for making such a mess. Carlotta then takes the food back to the table for Eric, Grimsby, and Ariel. The next day Carlotta is seen waving goodbye to Eric and Ariel as they leave to take a tour of the kingdom. Carlotta is finally seen again at the end at Ariel and Eric's wedding to where she becomes overly emotional and cries in Grimsby's shirt.
Carlotta appears again in the sequel but has a smaller role than in the previous movie. She is first seen singing "Down to the Sea" and celebrating the arrival of Eric and Ariel's daughter Melody. Then, when the party gets interrupted by Ursula's sister, Morgana, Carlotta moves away from Morgana, frightened.
Carlotta is seen 12 years later cleaning up the party for Melody's twelfth birthday party. When Ariel asks Carlotta if she's seen Melody, Carlotta replies, "Not since this morning, Your Majesty". When Chef Louis ruins Melody's birthday party by chasing after Sebastian and making everyone laugh, Carlotta splashes him with a bucket of water and says "Oh, Louie!"
In the end after the defeat of Morgana, Carlotta is seen celebrating along with the humans and merfolk by singing the song "Here on the Land and Sea". She then picks up Chef Louis and dances with him.