Create a Swimming Mermaid Tail with your own Fabric Design!

Posted by Customer Service on

 How to design a Swimming Mermaid Tail, from fabric design to sewing it up!

My daughter recently celebrated a birthday and asked for one thing - a Mermaid Tail that she could swim with in the pool.  And she has loved it, LOVED IT!  Pools are tough on stretchy fabrics though and standing on the pool bottom proves tough on even the best cared-for tail.  Pool bottoms are painted to be rough to keep you from slipping, so just standing on the floor rubs up the fabric of the tail.  So, the original is awesome but we wanted to sew up our own from start to finish and have our backup tail ready(for half the price).  Let's see what we'll do.

  1. Get the mono-fin
  2. Design, upload fabric design to, and order 1 yard (for a child)
  3. Measure fin and mermaid
  4. Cut (your own designed fabric!) according to measurements, two identical pieces
  5. Put fabric right-side to right-side and sew with serger machine or use the elastic stitch on regular machine. Polyester threads since tail will be wet often.
  6. Insert the Mono-fin so your Mermaid can try it on!
  7. Sew in elastic for waistband
  8. Ta da!  Go swim, always with adult supervision

Difficulty:  Easy plus.  Let's leave it at that for now and explain the plus at the end...

Step 1: You need a mono-fin.  Just like swim fins but the feet are together, as you would imagine for a mermaid.  Check them out at Swim, click here.  This fin slips inside our Mermaid Tail and provides the mermaid kick for the wearer, and quite the workout too! Monofin needed to swim like a mermaid

Step 2:  Design fabric!  Spoonflower is an amazing company that lets you design your own fabric by uploading your design and then printing on the type of fabric you choose. You can also choose from gazillions of other patterns from other Spoonflower artists.  For this project we will be using their Sport Lycra Fabric which is stretchy like a bathing suit material. And at 56" wide, 1 yard will be enough fabric.  It cost us $28 plus $6 shipping, we received a discount for creating our own design.  We designed a rainbow scales pattern colored with pastels.  To check color, we did order a swatch.  Shown right is our drawing before upload and our swatch.

Also shown is a drawing of the direction of the pattern.  We chose to make scales so they needed to repeat like stripes running up and down(not across) so that we can cut the 2 mermaid pieces as drawn.  Direction of fabric is sometimes very confusing, hopefully these simple drawings help you see fabric like you would see it on a roll at the fabric store.  To change direction simply rotate this image before uploading.  Same image just sideways. This allows you to just buy one yard since this type of fabric at Spoonflower is 56" wide.  For a link to our fabric on, click here.  Spoonflower has many tutorials on how to have repeating patterns, we have some notes next for this "almost a stripe" pattern.  Note: most of the scales we found on Spoonflower run the perpendicular direction so not ideal for 1 yard of fabric for a tail but many are much more professional than our drawing(but that's half the fun!).

  Two scales patterns we drew and the printed fabric swatch for each.Swatches from our design printed on fabric at Spoonflower


notes for making your own mermaid tail

An attempt to draw out the direction of the scales so they will be correct for your yard of fabric.  From selvage to selvage, this stretchy fabric is 56".  One yard=36" will be enough to cut out front and back of mermaid tail. 

Notes on drawing the pattern for an easy repeat.  Spoonflower has some great tutorials but here is a quick couple of photos to help you draw scales with an easy repeat.  Something your mermaid can handle...

how to draw for a horizontal repeat when making a mermaid tail how to draw for a horizontal repeat when making a mermaid tail how to draw for a horizontal repeat when making a mermaid tail how to draw for a horizontal repeat when making a mermaid tail how to draw for a horizontal repeat when making a mermaid tail

We wrapped a card stock paper around itself and taped from the inside, so the tape is not in the way of our drawing.  Then using a paper towel roll to color on/put pressure on(you don't want to fold the sides) we started our scales across the end of one side to the other side.  Don't forget to add whatever color is at the top to the bottom so the repeat also works vertically(check second photo).  Now the pattern matches horizontally and we can unroll and connect the scales across the middle.  We used pastels so then we smudged the color in each scale.  Bottom photo shows the work in progress.  Scan it or photograph it very straight and crop tight on left, crop right at edge of paper and your scales should match!  Or be very close to matching, closer than mine, we had to do a lot of configuring because we weren't this smart first time around!  After you upload to Spoonflower you can tell Spoonflower how to repeat and it will happen automatically.  they have some editing tools there too, but this hopefully will be a good start.


Step 3:  Measurements and cutting.  So, first we traced around the tail.  Usually in sewing you trace and add an inch for seam allowance.  But since we are using a stretch fabric and we want the tail to fit snugly, we are going to cut right on the line and stretch the finished tail over the mono-fin. (the fin measurements cover the feet and are shown as 16x12" in the sketch right.

To measure the foot to waist tube of the tail, stand up your future mermaid and measure heel to waist.  My mermaid was 30". Again, so tail fits tightly I am laying out the pattern at just 26" so it will stretch up on her when finished.  This includes the 1" for the elastic waistband.  Keep in mind you can always make it a bit longer and roll down the waist with the elastic, or cut it off after your mermaid tries it on to see how far it stretches up on her(or your little merman, he can have one too!)

I also measured her around the waist to know what the waist end of the tube needs to be.  She has a 21" waist(ah to be young), so I will make the top of the pattern 11", including the seam allowance, so when finished the waist with elastic will be about 20".


Simple sketch of our final dimensions of our mermaid tail for about a size 6-7 kids.

mermaid tail design to plan fabric needs

In the sketch above the length from tip of fin to waist will be 38", 12" for fin + 26" for heel to waist, for our mermaid.  The fabric is 56" wide so we have plenty of room in width.  The fin is 16" wide so with two cuttings(front and back) we have 32" to cut out of a yard or 26", viola one yard does the trick.

 Two weeks later...the fabric is here!  We had a pixel problem with our repeat and Spoonflower emailed us to ask if we wanted to correct so they could reprint.  And we took them up on the offer.  Our repeat is not perfect but it is really hard to tell with all those scales.  But a pixel line would have shown as white, so really happy that our finished fabric did not have that! 

Step 4: Cut (your own designed fabric!) according to measurements, two identical pieces.

cut out pattern for monofin so you can cut out fabric for mermaid tail

We first cut out the outline of the fin on paper for our pattern.

layout pattern for mermaid tail mark waist measurement for mermaid tail draw seam line for mermaid tail

Fold the cut out fin in half as above, in the center of the fin.  Fold the fabric in half longways. Above, the white is the backside of the fabric and we folded over just enough scales to fit our fin.  Lay the fold of the fin on the fold of the fabric and then you can make one cut and get a symmetrical piece.  Like cutting out Valentine's Hearts.  Pins help you keep your place when outlining and cutting.

Next we measured to 26", our magic number as measured earlier and marked with our fabric pen. We marked it at the fold.  From there we went out 5.5"(half the waist measurement).   And in the third photo shows us connecting the base of the tail(in cut out paper) to the waist mark at 26"/5.5". 

 copy mermaid pattern for second cut out for mermaid tail  mermaid pattern for mermaid tai two finished pieces for mermaid tail, ready to sew!

Once we had one tail cut out, we made another long fold in the fabric(fold to fold, first photo), traced the first cutout(first, second photo) and got a duplicate fabric tail piece(third photo opened up).

Step 5: Put fabric right-side to right-side and sew with serger machine or use the elastic stitch on regular machine. Polyester threads since tail will be wet often.


Now the Fun Part!  We tested our serger settings(first photo) to make sure they were good for this fabric. We put the two pieces right side to right side(second photo) and then we sewed all around the tail, except the waist(finished, third photo).

Step 6: Insert the Mono-fin so your Mermaid can try it on!


Almost there!  Once the long seam is sewn all the way around the tail, we turned it right-side-out (first photo) and slipped the mono-fin into place(second photo).  To get the fin in you need to roll it up, stretch the fabric and gently work it in place.  Then of course my mermaid had to try it on!

Step 7: Sew in elastic for waistband

 sew elastic for mermaid tail waist sew elastic for mermaid tail waist sew elastic for mermaid tail waist sew elastic for mermaid tail waist

The waist was easy since the whole tail is stretchy, the waist is already just about the right size. We cut the elastic 21" and sewed a zig zag stitch on the regular machine, then cut off the extra(first photo). I made it slightly smaller than the inside of the mermaid tail waist.  Then turned off the knife on the serger and serged the elastic to the wrong side of the waist, stretching if necessary for it to fit uniformly(photo 2).  Fold over the elastic(photo 3) and sew a zig zag or other stretchy stitch.  I stitched right over the serged stitches on the inside and stretched a little as I sewed to keep it stretchy when finished(photo 4).

Finishewd Mermaid Tail, ready to go swimming!

  Mermaid Tail for swimming

Viola!  The finished Mermaid Tail!  My mermaid has not had a chance to swim in this one yet, but we will update the blog post with her review of the fabric in the water (and my sewing skills).  Also, see Disclaimer 3

In the beginning of this article I wrote "Difficulty was Easy Plus".  Tracing, measuring, cutting and sewing one seam and the elastic is very simple and easy by most standards.  We were done with day 2 in less than 2 hours.   Which is why I wanted to make another tail!  But here's the Plus:  You need to get that monofin and no one sells it locally(to us) so that takes a bit of time.  To create fabric takes at least a week to print and ship, after you submit your design.  Just designing the fabric and getting the repeat right too, an afternoon.  So the prep takes a lot more than the actual sewing.  Easy Plus (a lot of prep).

Disclaimer:  Your mermaid really does need to know how to swim to use this tail in the water.  It does get heavy with water and they cannot easily get out of the whole tail quickly like they could with just separate fins. Mermaids must always swim with adult supervision.

Disclaimer 2:  Having just one makes for a jealous pool!  You might as well make two and share!

Disclaimer 3:  Also remember you will probably need to make one for your American Girl Doll...


If something is not clear or you need other help, please ask us!   We love happy comments too! 

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  • ?YOUR mermaid fin project is ABSOLUTELY-AMAZING-&-NEAT-O!!! ???✌?️

    Connie on

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