DIY Mermaid Costume

heather handmade sewing

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Make this easy DIY mermaid costume for Halloween! It looks like a mermaid but the special “tail” skirt makes it easy to walk and run!

I decided to really get into my kids DIY Halloween costumes this year since they are old enough to request and appreciate the costumes. I actually made them as easy as possible, but they look pretty complex. I loved watching their faces as they saw their Halloween costumes come to life.

I just love the magic and intrigue of mermaids! There have been times in my daughters’ childhood that they want to be a mermaid when they grow up, and I love their imagination. Learn how to make a DIY mermaid costume!

diy mermaid costume

Do you love sewing mermaid projects? Check out these:

diy mermaid costume

DIY Mermaid Costume

My daughter went through 50 ideas of what she wanted to be for Halloween (like a DIY rainbow unicorn) before I made her choose just one. But once she saw the fish scale fabric and the coordinating sequin fabric she was able to decide. She sounds like me, letting the fabric guide my decision. 

diy mermaid costume

She wanted to be just like Ariel, but I knew it’d be cold so she needed more coverage. I made a sequin tee with a tiny tulle edge on the hem.

Then I made a fish scale skirt with a puffy, tulle mermaid tail. The top of the skirt is a fitted pencil skirt and the tail poofs out at the bottom.

The front of the skirt is long to mimic the tale, but the back of the skirt is cut up above her knees so she can still run.

diy mermaid costume

She’ll have to wear layers underneath to stay warm and maybe even a jacket over top. I love that the skirt hides her shoes and she can wear any warm shoes underneath.

I hot glued shells to clips for her hair, and I glued shells around a battery tea light with a ribbon attached so it looks like her voice is glowing inside.

diy mermaid costume
diy mermaid costume

Do you love mermaid projects? Check out these:

I have since made lots of different mermaid skirts and costumes as my daughters have grown up. I usually stick to a shiny long sleeve top because we have cold Octobers, and then for the skirt I do scale print fabric for the fitted part and a gathered tier at the bottom for the fins.

I did this shiny blue top, green scale skirt, with gathered blue fins and green ruffles. My only wish for this one was to make the hi lo a little more extreme.

make mermaid skirt costume

I used the shiny top again and made an even simpler skirt. I did the silver scales and shiny rainbow fins. This one wasn’t used as much for a costume as much as it was used for dress ups and play time.

make mermaid skirt costume

DIY Mermaid Costume Tutorial

1. Make or buy a sequin tee shirt*. Sew on a piece of tulle to the hem.

2. Sew a some stretchy scale fabric* into a tube that is the circumference of your child’s hips. Add elastic that measures two inches smaller than the waist to the top so that it will stay up on the waist. (Here are some ideas for finding elastic to reuse.)

insert elastic to skirt

3. Cut the hem into a slight “V” shape with the point going down at the center front and the point going up at the center back.

4. Gather a bunch of tulle and sew it onto the bottom of the skirt. Trim the hem so it hits the floor in the same place all the way around the skirt. The back can be longer than the front.

pin tail to scale fabric

5. Glue some shells onto a clip or a headband for a mermaid hair piece. Do simple mermaid makeup.

make mermaid tail skirt
make a mermaid tail skirt

Make a Mermaid Tail Skirt with Tulle

Yield: One Mermaid Tail Skirt
Prep Time: 30 minutes
Active Time: 1 hour
Total Time: 1 hour 30 minutes
Difficulty: Confident Beginner
Estimated Cost: $20

Learn how to make a mermaid tail skirt with tulle! It's perfect for a handmade costume or just dress up time, and it's easy to run and play in!


  • Scale print stretch fabric (how to sew with knit fabric)
  • 3 or more yards of tulle
  • 1 inch elastic


  • Sewing tools
  • Sewing machine


  1. Measure the hips of you or your daughter. This will be the width of the skirt. Divide it in half to cut it out on the fold.
  2. Measure from the waist to the knee for the upper point of the skirt. Measure from the waist to the mid-calf for the lower point of the skirt.
  3. Whichever point you want to be in the front should be cut on the fold. The point you want in the back should be cut on the seam.
  4. Cut six to eight pieces of tulle that measures from the knee to the floor. I used the width of the tulle for maximum volume.
  5. Pin the skirt seam right sides together and sew with a zigzag stitch or serger. Finish the raw edges if desired.
  6. Lay out all the pieces of tulle on top of each other matching up both short edges. Pick up one side and match it up with the other side and pin.
  7. Sew with a straight stitch and 5/8 inch seam allowance. This will form a giant tube.
  8. Cut elastic to fit your waist or your daughters waist snugly. Overlap the edges 1/4 inch and sew to form a tube.
  9. Pin the elastic to the top edge of the skirt distributing evenly. Zigzag the elastic to the skirt.
  10. Fold the elastic over so that it's enclosed in fabric and zigzag in place.
  11. Sew two or three rows of basting stitches along one long edge of the tulle.
  12. Pull the bobbin threads to gather the tulle. Gather it until it's a smaller circle about the size of the skirt.
  13. Divide the bottom of the skirt into four equal sections. Divide the tulle into four equal sections. Match up the four sections of both skirt pieces. Distribute the gathers evenly.
  14. Sew the two skirt pieces together with a zigzag stitch. Be careful while going around the points. Finish the raw edges if desired.
  15. Turn the mermaid tail skirt right side out for the perfect skirt!
  16. You might need to trim the tulle shorter so that the tail lays evenly on the ground. Make sure you do this while you or your daughter is wearing it.
  17. You finished!

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diy mermaid costume
heather sewing

I believe small sewing moments can create great joy. Find your own “right” way to sew. -Heather

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