DIY Dress/Tunic Sewing Pattern

Over the summer, we took a family trip to the beach. I definitely had some reservations as I was well into my 3rd trimester, work was pretty hectic for my husband, and you know, we have a toddler. Alas, the trip was deemed a mandatory family reunion and we really had no way of getting out of it (we did end up shortening the amount of time we were there though). Anyway, I decided I wanted to make the toddler a super cute, festive swim cover-up for the beach. I figured it would get lots of “oohhs and ahhs”, give me a new fun sewing project and who doesn’t love compliments?! I began searching for an existing tutorial or pattern on how to make a swim cover-up. Don’t get me wrong, I found plenty, but they either weren’t what I wanted or required me to purchase a pattern or both.

As usual, I decided to combine a bunch of different ideas and make my own cover-up out of a beach towel. The first hurdle I faced was the lack of a pattern. After a little bit of searching and some experimenting, here’s how to make your own, custom swim cover-up (or dress or tunic) pattern.


  • Pattern paper, poster board, cardstock and tape, etc.
  • T-shirt that currently fits or a size or two too big
  • Pen, pencil, sharpie, etc.
  • Straight edge
  • Scissors

DIY Sewing Pattern

  1. First, I need to clarify that I took the cheapest route possible when making this pattern. I found a ream of cardstock leftover from our wedding invitations (those went out about 4 years ago) and taped a bunch of pieces together. I wouldn’t say this is the best way to go about it, but it certainly worked. I’ve used the created pattern multiple times since and it’s still holding up. So, as the first step in creating your own pattern, prepare your surface whether it be getting the pattern paper ready or taping a bunch of sheets of paper together.
  1. Lay the t-shirt you selected as a guide out on top of the pattern paper. I decided to use a t-shirt that was one size up from my son’s current size. This served two purposes: 1) I knew that the garment would fit him for a little while and 2) I didn’t need to worry about accounting for seam allowances. Then trace the t-shirt outline onto the pattern paper. Unless you are planning on making a shirt, do not trace the bottom of the shirt.
Disclaimer: We are not now, nor will we ever be, USC Trojan fans. My husband’s family is hell bent on converting us and it’ll never happen no matter how many t-shirts they buy my son.
  1. Determine the length of your tunic/dress/cover-up and put a mark on your pattern paper. At this point, finishing the pattern becomes an exercise in eyeballing. I knew I wanted my pattern to be as long as the zipper (pictured) and to angle out to the sides slightly. I decided I wanted the left and right corners to stick out 2 inches more than the bottom of the shirt. Using my ruler, I connected the bottom of my shirt to the desired length. Follow the same process using your desired outcome.
Pencil was a poor choice in writing utensil, but you can faintly see the outline of my pattern if you squint.
  1. Cut out your pattern
  1. Next, we want to verify that the pattern is symmetric. Since we did a lot of eyeballing and t-shirts don’t always lie perfectly, this step is critical. Fold your pattern in half and trim accordingly so it is perfectly symmetric. Then, cut the pattern in half at the fold.
  1. Choose a piece that you want to be the front. Cut the neckline so that it drops 1-2 inches lower than that of the piece you chose to be the back. Label your pattern pieces accordingly.

And that’s it! Now you can create all kinds of dresses, tunics and swim-covers with a cheap and easy to make pattern.

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