How To Make A Mermaid Tail ~ Tutorial

When planning my daughter’s The Little Mermaid Birthday Party, I knew right away that our little mermaids had to have homemade tails. It was a must. So I did what any crafty, DIY mom would do and hit up Pinterest. I saw several versions of tails made out of a beach towel, but our party was in October and I didn’t want to have to sew towels.  

Not finding what I wanted, I set out to design my own. (Which I like to do anyway!) And if I do say so myself, they turned out perfect!

Little Mermaid Ariel Tail

I like simple, so these mermaid tails make a big impact with very simple steps. I think it took me about 20-25 minutes per tail start to finish. I know that sounds like a lot, but it would have been quicker if I cut all of the fabric at once instead of one at a time. Plus I made it up as I went a long!!!

Mermaid Tail Materials

Little Mermaid Tail Tutorial Materials

Since my daughter’s birthday is in October, I got lucky because there were many specialty fabrics available for costumes. My fabrics came from JoAnn’s, but I was told that the Foil Mermaid fabric is only available for Halloween. In fact, I had to go to two stores to buy enough because each store only got one bolt. 

I was not able to find the fabric online, but I did a Google search for “Green Foil Fabric” and found both an eBay and Etsy seller selling a green foil fabric (with out the pattern) that would look nice.

Little Mermaid Tails


Measure your little one from her hips to the ankle and then her waist. My daughter 5-year-old daughter is 22 inches from her hips to ankle and 23 around the waist, and my two-year-old is 18 inches from her hips to ankle and 19 around the waist.

I made all of my measurements for the tails off these measurements. Adding to subtracting a couple of inches for kids I knew were a little shorter or a little taller. Since it is a tail, nothing needs to be precise, but I did try to make them a custom fit. You can use my basic measurements or measure your own kids.

For the length, I added 2 inches. For the width, I added 3 inches for a gather.

I cut my fabric approximately 24 by 26 for my 5 year old, and 20 by 22 for my 2 year old.

Tip, I use the grout lines in my tile to guide my scissors for a straight line. It works.

Mermaid Fabric Tail Pattern

I wanted the tails to slip on over clothes, so I also added 2 inches to the waist measurements for the elastic measurement. 

For the big girls, I cut 10 inches of tulle and for the little girls 8 inches of tulle. I used the entire width of the fabric.

Creating the Tail “Skirt”

Starting with the waistbands, fold the top of the fabric over about an inch and a half so that the “ugly” sides touch. Then sew a channel for your elastic. Then feed the elastic through the channel.

Tip, I attached a safety pin to the end of the elastic and hooked that onto the end of pencil to help guide the elastic through the channel.

DIY Little Mermaid Tail

Next, overlap elastic and sew ends together. I overlapped about an inch so there was room for clothes under the skirt.

Tip, before you sew it closed, safety pin it closed and check the width on your little one.

Sew Little Mermaid Tail

Once the elastic is sewn together, bring the two ends of the fabric together, overlapping slightly, and run another stitch down the middle. This will close off the top of your tail “skirt.”

That’s it, that’s all the sewing. Just 3 lines.

Assemble the Tail

The tail portion is super simple. Start with your tulle and gather it, accordion style. Wrap a clear elastic hair tie around it, tight. I left 3 inches on the big girls’ tails and 2 inches on the little girls’ tails at the top to help it stand upright.

Then fan out the bottom.

Mermaid Tail How To

Gather the fabric of your tail and lay it over the tulle. I left about two inches of purple tulle visible under the green fabric. With your green fabric gathered on top, wrap another clear elastic tie around the bundle placing it over the other elastic tie. 

DIY Mermaid Tail Back

Fluff and spread out your green fabric, making sure that when it hangs it covers the purple tulle on both sides.

When you are done, you will have an open “skirt” that gathers into a tail at the back. Easy to slip on and off over clothes during the party.

Homemaid Mermaid Tail Back

Note – the tulle from one tail did fall apart during the party (kids pulling on it), but I just grabbed another elastic and reattached it. My girls’ tails are still intact and now live in our dress up box.

I hope your little one enjoys her mermaid tail! If you are planning a birthday party, check out more pictures from our The Little Mermaid birthday party for inspiration and free printables.

Little Mermaid DIY Tail

Having a The Little Mermaid party? Get more inspiration from my other party posts:

17 thoughts on “How To Make A Mermaid Tail ~ Tutorial”

    • To figure out the size for a group of four year olds, start by measuring your daughter. Measure her waist and the length from her hips to ankles. For each measurement, add 2 inches. That will give you the fabric size you will need for each tail. You can see my measurements for a 5 year old and 2 year old in the post. The measurements don’t have to be exact. I made all of the 5 year olds costumes one size and all of the 2 year olds another. Hope that helps.

  1. Just made my first one, and love how it turned out! Going to be making about a dozen of them for my daughter’s birthday party. Thank you!

  2. Hi! I just found this fabric at Joanns yesterday and am planning a little Mermaid party for my 3 yo daughter for January! What kind of needle did you use for this fabric? Universal or ballpoint? Thanks!

    • Perfect timing because you really can only find that fabric when the Halloween materials start to come out! (My daughter has an Oct birthday.) I used Universal. I am lazy and use it for everything 🙂 Have fun!

    • Hi Lauren – Sorry, these were a labor of love. I love to create things for my daughters’ parties, but I am not available to make them for sale. But I take this as a great compliment, and I appreciate it!


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