When she is a mermaid, Ariel wears nothing but a seashell bra, which shows off a bit of her cleavage. This is the case for all mermaids featured in the film.
There is a scene where Ariel is given a bath. While no private parts are seen, it is clear she is fully nude.
Ariel needs Eric to kiss her in order to remain human. He nearly does so after some persuasion, but Flotsam and Jetsam capsize their boat and put an end to it.
After Flounder and Sebastian get the now-human Ariel to the surface, her buttocks are briefly visible again when she takes her first breath. Also later when Ariel tries to stand up in the shallow water, there's a brief view of the side of her buttocks.
Ursula's breasts often bounce. In one shot, she shakes them and the camera zooms in on them.
Ursula tells Ariel to use body language to attract her man, and dances sensually, by moving her hips. Before, she was using a sensual dance move when a woman moves their shoulders to move her breasts.
Ariel begins to transform into a sea polyp and her shell bra disappears. In one brief shot, her breasts are bare, with her arm covering her nipples. Her bra reappears once she transforms back into a human.
When Ursula turns into a human to seduce Prince Eric in one shot she rubs one of her breasts against his arm while cuddling him.
At Ursula and Eric's wedding birds fly under Ursula's dress making it fly up giving a split second view of her panties.