DIY Fishtail Mermaid Skirt with Train for Belly Dance, Halloween & Festivals

The last of the Mermaid Costume series is this beautiful fishtail mermaid skirt! 🙂

Last 2 weeks, we made the mermaid shell bra top and the curly seaweed armband!

And today we’ll complete the costume with this fishtail mermaid skirt with a little train. It’s pretty simple to make, yet looks pretty impressive when it’s finished. Let’s get started!

Click here to get the calculator for making this mermaid skirt!

To make this DIY fishtail mermaid skirt, you need:

Pattern paper – this can be any lightweight paper like craft paper. You need about 50cm x 1m (20in x 39in).

About 2m (2yd) of stretch fabric

Matching color thread

How to Make DIY Fishtail Mermaid Skirt with Train

Take measurements

First, take these measurements:

Your belt line – this is where you want the waistband of your skirt to sit. I’m making this skirt as a belly dance skirt which usually sits below your belly button, but if you’re making it for a different purpose, adjust as you like.

Your hip line – this is the circumference of the fullest part of your hips.

Your knees – Measure around both your knees together.

And we need to get 3 vertical measurements. From your belt line, measure: 

At your hipline which is the fullest part of your hips

At your knees 

At the floor

It’s best if you have someone to help take these vertical measurements on the back of your body since the back side tends to have more curves. This way, we can make our skirt according to the longer measurements of our body. It’s easier to shorten a skirt then to lengthen it! 😉

That’s it! So using these numbers, let’s make a simple pattern.

Quick calculation (or use my calculator)

To do that, we’ll do some calculation. I’ve put together a special calculator that does all the calculation for you for this mermaid skirt, and you can get access to it here. But let me quickly explain the calculation part.

So take the belt line measurement, and divide it by 1.15. We’re using stretch fabric to make this skirt and it should be fitted, which means the actual skirt is going to be smaller than your measurement. That helps the skirt fit you well. And this division helps us shrink your measurements evenly. 

Then divide the number by 4, because we’re making a ¼ pattern, and add 1cm (3/8in) for a seam allowance. So that’s your belt line number for your pattern.

Similarly, for the hip line measurement, we divide it by 1.15, then divide it by 4, and add 1cm (3/8in). That’s your hip line number.

For the knee measurement, let’s use the number as it is because the skirt doesn’t have to be so fitted around there. The extra room allows your legs to move freely. So just divide it by 4, and add 1cm (3/8in). That’s your knee number. 

Also, for your vertical measurements, find the difference between each point to find out the distance between them. So for example, take the knee measurement, subtract the hipline measurement, and that’s the distance between your hipline and knees. Do this for all these parts. 

Again, you can skip the calculation by going here! 🙂

Make your fishtail mermaid skirt pattern!

On your pattern paper, draw a vertical line on the left side. And draw a horizontal line at the top that’s perpendicular to the first line.  

On the horizontal line, measure your belt line number that you calculated or found in the calculator, from the vertical line. And make a mark right on the line.

From the horizontal line, measure 2.5cm (1in) down and draw a line that’s the same length as the belt line number.

From this line, measure the distance between the belt line and hipline, and from there, draw a horizontal line. This should be the length of your hip line measurement that you calculated.

From this line, measure the distance between your hipline and knees, and go down extra 10cm (4in). From there, draw a horizontal line that’s the length of your knee measurement that you calculated. 

And go down 1cm (3/8in) from there, and draw another line of the same length. 

Now connect the ends of all these lines, and at the hip part, make the line smooth and round so there are no sharp corners. And draw fold arrows along the vertical line, so you know to place this pattern along the fold of your fabric.

Cut along the outer line, and that’s your pattern!

Let’s start cutting fabric.

Cut fabric!

First, fold your fabric right sides together so the direction of the stretch of the fabric is perpendicular to the fold. And place the pattern right against the fold. And cut according to the pattern.

Repeat so you have 2 panels.

Next, fold your fabric right sides together again, but this time the direction of stretch doesn’t matter. But if your fabric has a pattern like mine, then make sure the top down direction is along the fold of the fabric.

From the top of the fold, draw a horizontal line perpendicular to the fold. From there, measure your knee measurement (actual measurement, not the one you calculated to make the pattern above) divide by 6 all the way to the fold. So you have a ¼ circle drawn here like this. 

Then from the ¼ circle outline, measure the distance between your knees and floor minus 8cm (3 1/4in). You can find these numbers in the calculator as well. Now you have a larger ¼ circle like this. 

Cut along those 2 lines, and you have a half circle panel. 

Now, you can make another one that’s identical. That will make a nice mermaid skirt, but in this tutorial, I want to make it into a train skirt that drags a little behind me. 

So fold the fabric the same way, and draw the smaller ¼ circle again. Then, at the top edge, mark the same distance between you knees and floor minus 8cm (3 1/4in). 

Take that number, and add 15cm (6in) to it. Measure that along the fold from the small ¼ circle. 

And now connect these 2 points with a nice curve. Make sure the distance between this line and the small ¼ circle stays larger than the distance between your knees and floor minus 8cm (3 1/4in) (i.e. the measurement of the straight line at the top). 

Then cut this panel out.

Alright, let’s sew everything together! The sewing part is very simple.

Sew!

First, place the top panels right sides together, and do a zigzag stitch along the sides with a 1cm (3/8in) seam allowance. 

Then place the circular panels right sides together, and align the straight edges. Do a zigzag stitch with a 1cm (3/8in) seam allowance. 

Now have the top part right side out, and the bottom part wrong side out. Take the bottom end of the top part and place it on the inside of the bottom part of the skirt. The right sides are facing each other.

Match up the side seams, and the rest. And do a zigzag stitch all the way around with a 1cm (3/8in) seam allowance. One edge may be a little longer than the other, but it’s okay. Just try to match up as best as you can, and pull the layers gently to align and sew them together.

Now let’s finish the hem. You can simply fold 1cm (3/8in) from the edge towards the wrong side, and do a zigzag stitch all the way around. Pressing the seam at low heat helps settle the hem nicely.

Now put on this skirt, and see the length.

Here’s a super easy way to adjust the skirt length – We haven’t finished the waistband part yet, so fold in the top to adjust the length. Since we based the pattern on the measurements on the back side of your body, it may be a little too long on the front side. That’s perfect! Simply adjust by folding in, and place pins or clips at the front, back, and sides. 

Do a zigzag stitch with a 2.5cm (1in) seam allowance here, and if there’s excess fabric, just trim it off. If you like, you can sew in elastic here, but an elastic waistband creates a muffin top effect very easily. So that’s why I made this pattern based on my measurements and yours on your measurements so the skirt will stay up without elastic. 

If for some reason the skirt feels too loose, you can add elastic after you finish this part. Here’s a tutorial on how to do that!

And now your mermaid skirt is complete! It’s perfectly fitted, and it flares beautifully as you twirl. The little train is romantic, and of course, if you want a more dramatic one, go ahead and make it longer. It’s such a pretty skirt, perfect for a mermaid costume!

This mermaid skirt can be made with different stretch fabrics and used for many belly dance styles as well as festivals!

If you’re into fusion or festival looks, check out these too:

I hope you enjoyed this mermaid costume series and this fishtail mermaid skirt tutorial, and if you did, please share this tutorial with your dance sisters and festival friends!

And if you want to learn how to make more belly dance costuming items, sign up for my free email course, Belly Dance Costume Making 101. You’ll find lots of beginner-friendly projects that will make your costuming more fun!

Thanks for reading, and keep sparkling!

P.S. Pin this image on your costume design board!

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