Mermaid Costume from 2 T-shirts

This costume is from last year as well as the Vintage muscle man costume -  my daughter wanted so badly to be Ariel from the Little Mermaid, but I really didn't like the ones I found in the store - mainly because of the price tag, and for some, the lack of modesty.  I decided to give it a go with 2 tshirts, which I found at Goodwill for less than $5.  I bought them in the men's section and got the largest ones I could find so that I'd have some extra fabric if I messed up.

For the top, I cut off the neckline ribbing and the sleeves, then put it on her inside out, pinning it to the correct size.   I also measured where her hipline was, so I knew where to attach the skirt portion.

After trimming it all down, I sewed the side seams and folded under the neckline and topstitched with a straight stretch stitch.  I didn't have to do any shaping to the neckline other than cutting and folding - it gave it a cute boatneck shape.  For the sleeves, I left the edges raw and gathered it right in the center, stretch stitching it in place for a cute little ruffle.

For the shells, I cut out a little shell shape on paper to use as a pattern, then cut 4 pieces out of the leftover purple tshirt and 2 pieces out of the quilt batting (the same kind I used in the muscle man onesie)  Layer 2 pieces of purple and put one piece of the batting on top.  Pin together.  Sew around the sides and top, leaving the bottom open for flipping.

View from the underside

View once it's been flipped.

 Sew three lines down the center and baste the bottom closed

Gather the bottom and repeat with the other side.

Take a piece of the neck ribbing that you cut off and sew it right sides together to one shell, then the other, so that the seams are on the back.  Wrap ends around to the back and hand sew shut.

Figure out placement on shirt and tack on (hand sew) at center and sides.

 Now for the skirt.  This part was the hardest, but mostly because I had to work around some writing that was on the back of the shirt and I didn't have as much fabric as I would have liked.  I therefore had to get VERY creative ;P

Here's what I came up with…bear with me - it's been almost a year and I'm trying to remember how I did this looking solely at these pictures ;P

Take your green tshirt and turn it so that the hem is facing you.  Measure your child and figure out where you want the point of the fin to be.  Cut the shirt off at that point:

Fold it in half and cut an angle from the bottom to the side where you want the side of the fins to start.

Put on your child inside out and fit it.

Now for the fins. 

Cut the rest of your shirt into usable strips about the same width and sew them all together, connecting them to make a tube.  If some are longer than others, that's okay.  Just trim them up so they're all even

Choose one of the seams as your center seam, and line up the point of the top of the skirt.  Trace along this part, and cut out the "V".  Gather the top of the bottom portion of the skirt, and attach to the bottom of the top part of the skirt.  Confused yet?  ;P  

I didn't take any pictures of this step because I came across some problems I had to fix.  At this point, the fins don't stand out very well.  What I did to fix it was cut off the t-shirt sleeves like this:

I gathered them along the straight side and sewed them into the top of the fin at the connector seam to give it some poof.  This is totally optional, but I feel like it made the fins stand out more.  Since I didn't take pictures of this part, here's where I mean:

Right where the arrows point, you can sew the gathered sleeves at the same time as when you attach the bottom of the skirt, or after.  Trial and error, people.  I had no idea what I was doing.

I then took 2 small strips of green fabric and sewed them to the "V"points in the front and back.  First I sewed inside, then wrapped it around to the front and attached it.  This, obviously, is a bit visible, so I added the ruffle along the seam line to hide it all.

To do this, I took some of the scrap fabric in strips, gathered it into ruffles, and sewed it to the top of the skirt along the "v" seam.  Sorry for the horrible pic, it's the best I've got.

Remember, tshirt fabric doesn't fray, so you don't have to hem or serge anything.  Just cut and go :D

Finally, sew the skirt to the top at the waist and you're done!

She LOVED it - still does, and wears it ALL.THE.TIME.  And I'm so glad, because I just about lost my mind figuring out how to make it ;P  Hope this saves you a little frustration by not having to start from scratch!