I know we technically finished our sewalong last week, but I was fussing around with a quick and dirty Nettie-to-bikini hack and I figured some of you ladies may want to do the same.

Converting this pattern is fairly straight forward – Nettie is a pretty basic leotard block and as such can be a good base for some good old-fashioned creative license. To get started you’ll need a yard each of swimsuit fabric and lining. The great folks over at Girl Charlee (rapidly becoming my most frequented online store) sent over some fabrics for me to play with. They are expanding their swim lycra offerings and have some really cute prints right now I haven’t seen anywhere else. I used this print for the front, this plain black lycra for the back, and this milliskin for the lining. I had never worked with milliskin before; I’m used to a more lightweight swimwear lining, but this stuff worked really well. It didn’t bulk anything up at all and adds great coverage. I would suggest using a skin tone for lighter prints though.

nettie swimsuit

First things first: we need to modify the pattern. If you’ve made a Nettie already, you can try it on and use it as a guide to decide how long you want your top and briefs. This is for my hairdresser (we barter clothes for service a few times a year). She has a very long torso so I had to guess where to cut things. I suspect I will have to trim the bottoms a bit at the waist once she has a chance to try it on.

Once you decide where your cut line will be on your pattern piece, you’ll want to add about 3/4″ to the width of the crotch seam, unless you want to use fabric binding like a regular Nettie which is totally an option. I wanted to experiment with elastic instead so I had to ensure the crotch was wide enough. The same principle applies for the leg openings. Since we’ll be folding elastic into the fabric, you’ll want to add a little bit to your seams – in this case I just traced the opening for one size larger. Additionally, you may want to move the crotch seam back. The Nettie crotch seem is a little forward for ease of unsnapping, but with the swimsuit you’ll want to hide the seam. I added an inch to the front crotch and subtracted an inch from the back.

For the top, I suggest using the scoop front/medium back variation. I thinned out the straps a little but you could leave them as if you want something with a little more heft. You’ll also want to drop the arm opening about an inch so you have a little bit more room under your armpits.

These are the essential changes I made to the front pattern piece (for a size 8). The same mods will have to be made to the back, but keep in mind you’ll be subtracting a little from your back crotch seam.


Once you pattern has been traced with the above modifications, it’s time to cut out your fabric. Once again, I recommend using a rotary cutter – swimwear lycra is really slippery and it helps make the job much easier. Cut one each of the front and back in your fabric and lining.

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Baste your lining to your fabric pieces using a narrow zig zag or a long straight stitch (you can remove it later). Zig zag or serge your leg openings closed if you’ve added a  lining. We’ll then be sewing the bottoms together at the side and crotch seams using a serger or narrow zig zag stitch.

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For your top, baste the lining to the fabric at the side and shoulder seams. Serge or zig zag your arm and neck openings and along the bottom seam of your top.

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Now you can sew your neck and front pieces together at the side and shoulder seams.

Once you’ve got your top and bottom assembled, it’s time to add elastic. Make sure you use elastic made for swimwear – the regular polyester stuff breaks down in chlorine. For the first step you will be using a wide zig zag stitch to secure it the wrong side of the fabric. I did this mostly by feel since I’m very comfortable sewing in elastic after I don’t know how many Bombshells. For the bottoms, you need hardly any stretch at the waist. Just very gently pull your elastic as your are zigzaging it down to the fabric.

At the legs, you want some stretch around the crotch area so you don’t have any gaping. I gave the elastic a very subtle stretch along the outside of the legs; as I approached the crotch I stretched it approximately 15%. If you stretch the elastic the same amount around the whole leg opening it will cut into your skin.  You can see below that is only really stretched around the crotch area (hence the ripples).

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Once you’ve secured it down, flip the elastic to the inside and use a medium zig zag stitch to topstitch it into place. Sew close to the edge of the elastic so it doesn’t flip up on you.

nettie swimsuit-4

Bottoms done!

For the top, I would only use a very subtle amount of stretch along the arm and neck openings. Again, skin digging is no fun. I would add that 15% back into the bottom though, as you want the seam under your bust to stay nice and secure. No lost bikini tops on the waterslide, please!

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And that’s it! Normally this is something I would cover over several posts so feel free to comment below if you have further questions. I tried the top on and it is SUPER cute and I think my hairdresser will be super happy when she gets her new bikini. Which is good because the grey is starting to come in pretty hot and heavy and it might be time to start dying this mane….

Core Fabrics


Closet Core Patterns

Hi! I'm Heather Lou, a pattern designer and sewing educator for the modern maker. At Closet Core Patterns, we transform your imagination into step-by-step implementation that helps you create a wardrobe you love - not one you're limited to buying off the rack.

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