My little girl wanted to have her own mermaid tail when she wasn’t even two years old. Since I had some left over fabric from the tail I had made at that point I decided to try and make her a matching tail.
The tail is open at the back and I used small buttons to close it loosely around the lower part of her legs if she wanted too. It’s open at the feet so she can walk in it too and since the tail was made of Lycra materials it would also be swimmable.
Here is a sketch I made on the measurements I needed to put this tail together:
And this was the result:
I have made a video that I uploaded to YouTube which shows step by step how I made this tail for her: