I am not generally one for leaving things to the last moment but on this occasion I was making this mermaid costume a day before the party. What saved me the most was the fact that the fabric didnt fray, no hemming required and I used an old t-shirt, a half made top. So it really only took a small amount of time to make and then glue on some embellishments.
My daughters response the next day “Awesome, Awesome, Awesome”. Thumbs up.
If I hadnt left it to the last minute I would have put together a better tutorial but it is pretty simple.
So first off the top.
Get an old shirt and unpick a 4 inch (10cm) gap right underneath the armpits on both sides. With your chosen mermaid fabric (I think mine was lycra, non-fray) cut a rectangle with a width of 10cm and the length of the tshirt plus 1/2 inch (1.5cm) for seam allowances on both sides. In the center of the rectangle I ruched it by using a gathering stitch and pulling the thread till it bunches up. Turning the shirt inside out I place the rectangle inside and pinned to where the gaps are (make sure the sparkly side is facing the right way). Sew the gaps closed. Turn right way out and then I sewed the ruched section to the shirt and glued on a fancy button.
That part done!!!
Next the skirt.
I just used the width of the fabric off the roll (112cm or 44inches) folded in half and the lenth of my daughters legs to her ankles plus the elastic casing (2in/5cm), sew down the open edge. Then I measured the lenth to where I want the shortest part of the skirt to sit plus 2in 5cm for the elastic casing and cut out the arc (on the folded edge) to a width to where I will place the tail fin (11in/ 29cm).
Fold over the casing at the top for the elastic and sew down, leaving a gap to insert the elastic. Measure your childs waist and take 1 inch off for the elastic measurement, insert in the skirt, check that it fits right and then sew together.
With the width of the bottom of the skirt draw out desired fin shape (x2) in the lyrca and 1 with either felt or fleece again no fraying. Sandwich the felt inbetween the lyrca with the good sides of the lycra facing out and pop in some ribbon as the holder (tip: if right handed put the ribbon on the right side of the tail and then the same if left handed. It has to do with how the skirt hangs when on the arm. This tip I discovered after I made it). Pin three layers together and zig zag stitch them together. Pin the fin to the skirt (watch where the ribbon goes) and sew together. I top stitched that seam so it sat flat at the back.
To finish I put a button at the top near the elastic so when they have had enough of the skirt hanging off their arm they loop it to the button (up there for thinking hey!!)
Now using the scraps and a bit of tulle you can make a lovely head piece to go with it.
I hope this was easy enough to follow. Got any questions dont hesitate to ask.