Hi everyone! It’s Abby, that random kid (and tester) who stalks the KPD Facebook group. Today I’ll be showing you how to transform the Shelby into a swimsuit!

The first thing I thought when I saw the Shelby was: that would make an awesome swimsuit! I was right! With only a few easy mods, I now have an amazing tankini.

Don’t have your Shelby pattern yet? Click here to purchase it.

Let’s get started!

We will be lining both our top and shorts, and adding bands instead of hemming. We will also be adding a shelf bra to the top!

To make a Swim Shelby you will need:

Swim fabric, you may want to get a little extra for the bands

Swim lining

¾” Elastic

Adjusting your pattern

The first thing we need to do is completely straighten out the side seam. If you don’t do this the child’s top will completely fly up in their face as they swim. Simply extend the straight line from the armscye. You may also want to shorten it since we will be adding a band instead of hemming.

Get creative with the lengths! You could easily make this as a bikini top, or just shorten it a little to show a little skin.


I had an issue with the swim fabric always riding up around my legs and stomach, so I decided to add bands at the bottom instead of hemming.

To do this:

Measure the length of the hem on the shorts and double it. Cut 2 bands:

Width: measurement x 2 – 1”

Length: 2x your desired finished width. Remember to add ½” seam allowance. (For a size 14 I chose 3.5 which equaled 1” after being sewn on)

Remember to trim the original hem allowance off of the shorts leg length prior to adding the bands. If you do not do this, your shorts will come out too long.

Do the same thing for the bottom of the top, except multiply the length by 4 instead of 2 because the top is cut on the fold.

Ex. For the bottom of my top:

Length: 8 x 4 – 1.5in = 31.5 in

Width: 4.5” for a finished width of 2”

Cut your bindings and waistband as you usually would, from swim fabric. Cut one main and one lining for each pattern piece except the bindings & waistbands.

Adding the shelf bra

Grab your top pattern again. Measure from the armpit to where you would like the shelf bra to hit. Add 1 ½ inches to that number. Measure down that number from the armscye on your pattern piece. Cut the pattern off at that point. Ex. My length was 3” + 1 ½” = 4 ½”

Measure in 1” from the bottom of the shelf bra. Mark that point and slant it up to the top of the armscye.

Cut 2 shelf bras from swim fabric. Lastly, cut a piece of ¾” elastic the length of the underbust minus 2”.


Instead of sewing on your neck bindings first, sew each set separately (lining side seams, main side seams, and shelf bra side seams)

Take your elastic and stitch it into a loop. Overlap by ½”. Mark quarter points on the elastic and shelf bra.

Match up the quarter points of the shelf and elastic with the elastic to the wrong side of the shelf bra. Stitch the edge of the elastic to the edge of the shelf bra, stretching to match the quarter points as you go.

Flip the elastic up to the inside so it is now enclosed. Topstitch the elastic down at the top of the elastic.

Slide the lining into the main wrong sides together. Then slide the shelf bra into the lining with the wrong side of the shelf bra facing the right side of the lining. Pin.

Baste together at the armscye, neckline, and the hemline.

*Tip: Don’t worry about keeping everything lined up. Swim fabric is very slippery and it will likely slip on you, but you can trim it off later.

Then attach your bindings. I found it easier to use  the tradition knit binding method, where you stitch on one of the outside pressing lines and then fold everything back up. Video tutorial here.

Tip: When ironing swim fabric, it must be on a low setting or your fabric will melt.

Instead of hemming, sew on your band the same way the shorts waistband is attached on the pattern, except you will not need to stretch at all.

*Tip: Try on your top before attaching the band. You may need to take it in a bit.

Your top is now complete! Onto the shorts…


Construct the main and lining shorts separately until you have to add the waistband. Before attaching the waistband, slide the lining into the main wrong sides together and baste at the waist and hems.

Attach your waistband. Instead of hemming, attach your leg bands the same way as your hem band on the top.

Your Swim Shelby is officially done!!

That wasn’t too hard, was it?

We would love to challenge you all to sew up a modified Shelby into a super cute and trendy swimsuit!

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