I tried sewing my first swimwear without a pattern or instructions. A “learning experience” project, not actually wearable. I wore it to a hot spring anyways but won’t keep it, the sewing and fit is just too poor, the fabrics aren’t correct.
I traced off my favorite workout sports bra and a pair of underwear, added 1/2” seam allowance, though in the future I should have added more - maybe 5/8”? I used two thrifted pieces of fabric, neither of which is really proper swimwear fabric. I found it hard to sew evenly with, and difficult to manage the two fabrics which were very different in their thickness and stretch characteristics. This did inspire me to learn about the walking foot and use it for the first time, which was good thing to learn.