This Little Mermaid Ariel dress costume is long, flowing, and elegant. For this costume, you can even wear a mermaid dress! As long as it has the right colors, then it will work well for this costume. You should try to find a dress that’s aqua colored or something that has the colors of the ocean all over it. You can add the purple felt shells that cover the chest to give it an unmistakable mermaid look. If you want to go all out on this costume, you can either get a Little Mermaid Ariel wig or just dye your hair red. Split your hair towards the right, add a small shell hair accessory and you’re all done with your Ariel costume.