I'm not strictly doing these in chronological order, it's just a coincidence that I chose Ariel next. You might think Ariel isn't a Mary Sue because of her obvious flaws that a lot people hate her for, but I think she still could be. Mary Sues can have flaws (hence why that trait doesn't just say "No flaws" and nothing else). So let's see.


Unique traits without contacts or hair dye- Sort of. Red hair is common enough, but her shade of red definitely isn't. .5
An odd name- Sort of. 'Ariel' is common enough by mermaid standards, but she's the only one of her siblings with a name not ending in A, which is a big Mary Sue trait - being "special" or "different". .5
Looks constantly commented on- Yes, but only by Eric, and it makes sense that he would focus on her looks. .5
Multiple characters falling for her- No, only Eric.
Gets into the relationships she wants- Yes. While meeting Eric wasn't her only reason for becoming human, it was definitely one of her main motivations. 1.
Always the hero- Kind of. She saved Flounder from the shark and Eric from drowning. So not a lot of times, and she didn't defeat the main villain while her prince did, but she also never had to be saved. .5
No flaws or any flaws addressed or causing a negative impact- No. Triton and Sebastian definitely call her out on her selfishness and recklessness, and her decision causes Ursula to nearly take over the kingdom. Though the one thing that kind of undermines this is that she gets what she wants in the end anyway. But I think it's enough to let her off a point or two.
Seen as perfect/angelic in everyone's eyes- Not really, only in Eric's eyes. Triton and Sebastian see her as an immature child, and most of the humans see her as weird instead of charming.
Always loved and trusted without earning it- Yes and no. It makes sense that Eric would be drawn to the girl who saved his life, and even then, she has to win him over after he doesn't recognize her. But her animal friends love and stay loyal to her even after all the trouble she puts them through (even if Sebastian complains about it). Triton doesn't count since she's her father and of course he'd always love her. Since this would usually get a half point for a one-point trait, it's getting one point. 1.
Love and trust from closed-off characters- No, I can't remember any closed-off characters in the film.
Other characters degraded for her sake- Not as far as I can remember.
A rival to make her look good- Not really. Vanessa (aka Ursula) is her rival for Eric's affection, but Ariel isn't portrayed as the superior love interest since Ursula never wanted to be Eric's love interest and was just using him.
Never fails- Kind of. The only thing she failed at was arriving for the concert, which she didn't care about at all. 1.
Never injured- Yes. I can't remember a time Ariel was injured. 1.
Always praised and rewarded without earning it- Yes. Even after all the trouble she caused, Triton just handed her her happy ending. 1.
Unrealistically skilled/powerful- Not really, she showed a realistic naivete and ignorance at being human (I should really focus on how good they are at things for this instead of focusing on the amount of skills they have - slight difference). Being able to save Flounder and Eric was realistic, and she didn't defeat Ursula in the end.
Always figures things out- No. She didn't figure out Ursula was tricking her,
Skilled in a wide variety of things- No, only singing and collecting things.
Contradictory traits- Not really (though in the sequel, she does, though I'm not discussing that)
Kind but deadly- Yeah, she's supposed to be kind and free-spirited but also feisty and rebellious. 1.
Tragic backstory- Sort of. Her life is pretty nice compared to the other princesses, but there's a lot of attention on how she feels trapped and oppressed and wants more. (That also describes Jasmine perfectly, now that I think about it) .5
Always gets what she wants- Definitely. She gets to leave the sea, get her prince, and even stay human. Even when it seems like she won't get what she wants, she does anyway. 1.
Rarely shows negative emotions- No. She gets angry quite a few times, and breaks down at least twice.
A resurrection- Nope.

That's 10.5 out of 24. Honestly more than I expected, but not a Mary Sue (though not a huge non-Sue, if that makes sense). That doesn't mean she isn't a bad character, which a lot of people would argue she is. In fact, you could argue she's too flawed and not idealistic enough.