How to sew a swimsuit

DIY, Sewing

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It can be almost impossible to find a swimsuit with the perfect coverage, a flattering silhouette and an impeccable fit. Why not learn how to sew a swimsuit instead? Get the sewing details of this halter swimsuit and see how I used this bustier swimsuit top to get the fit benefits of a two-piece with the coverage of a one-piece. Included are several tips for how to sew swimsuit material which, while it can seem intimidating, is really quite easy! Read on for all the details.

It can be almost impossible to find a swimsuit with the perfect coverage, a flattering silhouette and an impeccable fit. Why not learn how to make a swimsuit instead? Get the sewing details of this halter swimsuit and see how I used this bustier swimsuit top to get the fit benefits of a two-piece with the coverage of a one-piece. Included are several tips for how to sew swimsuit material which, while it can seem intimidating, is really quite easy! Make your own swimsuit, diy swimsuit top, how to sew a swimsuit, bustier one piece swimsuit, make custom swimsuit, how to sew swimsuit material




It can be almost impossible to find a swimsuit with the perfect coverage, a flattering silhouette and an impeccable fit. Why not learn how to make a swimsuit instead? Get the sewing details of this halter swimsuit and see how I used this bustier swimsuit top to get the fit benefits of a two-piece with the coverage of a one-piece. Included are several tips for how to sew swimsuit material which, while it can seem intimidating, is really quite easy! Make your own swimsuit, diy swimsuit top, how to sew a swimsuit, bustier one piece swimsuit, make custom swimsuit, how to sew swimsuit material

The pattern decision

My experience with sewing swimsuits for myself is pretty limited; but while this is only the second one I’ve made for myself, I’ve sewn quite a few for my kids! (read about those project here and here) The first suit I sewed for myself was a vintage style halter one-piece from a pattern I got in a Burda magazine. I’ve since misplaced that pattern but I definitely knew what kind of improvements I needed to make when sewing my next swimsuit.

The main problem with that first handmade swimsuit (and essentially every single one I ever try on) is bust support. I’m not particularly huge on top (between a C-DD for most of my adult life) but when you add in the stretched out skin (TMI, I know, sorry) from having multiple babies, bust support becomes non-negotiable.

I love what halter tops do for this issue so I knew that’s what I wanted at the top of this cute floral suit but I also knew that cups (preferably with underwire) would be a boon as well. I decided last year that I wanted to use the Sophie Swimsuit pattern and either make the one-piece suit or an elongated version of the two piece. However I’m not a fan of low cut swim bottoms (read why here!) so I knew that I’d raise those leg openings a few inches if I made the bottoms from that pattern.

Coincidentally, I fell in love with the black and white striped bottoms I’m wearing here when I saw them on sale at Asos and so I grabbed them a few months ago, before I ever had plans for this top. Then when production of this suit started, I knew that this color-blocked tropical floral print would be amazing with those bottoms! So alas: a match made in stripey-floral heaven. (I also found a few more cute high waisted bottoms from Asos: polka dots, plain black and colorful stripes!)




It can be almost impossible to find a swimsuit with the perfect coverage, a flattering silhouette and an impeccable fit. Why not learn how to make a swimsuit instead? Get the sewing details of this halter swimsuit and see how I used this bustier swimsuit top to get the fit benefits of a two-piece with the coverage of a one-piece. Included are several tips for how to sew swimsuit material which, while it can seem intimidating, is really quite easy! Make your own swimsuit, diy swimsuit top, how to sew a swimsuit, bustier one piece swimsuit, make custom swimsuit, how to sew swimsuit materialIt can be almost impossible to find a swimsuit with the perfect coverage, a flattering silhouette and an impeccable fit. Why not learn how to make a swimsuit instead? Get the sewing details of this halter swimsuit and see how I used this bustier swimsuit top to get the fit benefits of a two-piece with the coverage of a one-piece. Included are several tips for how to sew swimsuit material which, while it can seem intimidating, is really quite easy! Make your own swimsuit, diy swimsuit top, how to sew a swimsuit, bustier one piece swimsuit, make custom swimsuit, how to sew swimsuit material

Sewing Details

Now on to the sewing details of this DIY swimsuit top: First of all, I cut the top out of the one-piece version of the Sophie swimsuit (view A) and just ended it at the lengthen/shorten line. That hit me right at my natural waist so I knew it’d be the most flattering spot to start the peplum flounce.

The cups were a bit tricky for me…mainly because I diverted from the instructions! If you use the materials she suggests, you should have no trouble at all. But I got the notion in my head that I wanted to make this thing like 24 hours before I wanted to shoot these photos so I had to make do with the supplies my local fabric store had. I bought a couple of foam cup inserts and some boning, hoping that I could substitute that for the underwire (which my local store did not carry…*sigh*).

I pieced together the exterior of the cups and then skipped the instructions for cutting and sewing the foam (I’ll definitely try it the other way next time) and just basted the inserts inside the exterior of the cups. I also used tricot interfacing to line the cradle piece between the cups because, once again, that’s what I had. (I definitely fall in the make-do-and-soldier-on kind of sewing camp when I’m working on a project I’m excited about!)

Once that was all put together, the bra portion fit pretty well, except that the foam inserts were irregularly shaped at the top, and so they didn’t line the entire top portion of my cups. So, instead of trying to use the boning as underwire, I chose to use it to line the top edge of my cups, giving them some stability so they’d keep their shape when being pulled on by the halter straps.

And voila: it worked! It’s not perfect and I think I’d still like to add some underwire in hopes that the cups can give me more support, especially between them. I don’t love that that cradle section doesn’t hug my chest between my breasts but it was a small problem, considering how well the rest of it fits and feels.  Overall, a success!

It can be almost impossible to find a swimsuit with the perfect coverage, a flattering silhouette and an impeccable fit. Why not learn how to make a swimsuit instead? Get the sewing details of this halter swimsuit and see how I used this bustier swimsuit top to get the fit benefits of a two-piece with the coverage of a one-piece. Included are several tips for how to sew swimsuit material which, while it can seem intimidating, is really quite easy! Make your own swimsuit, diy swimsuit top, how to sew a swimsuit, bustier one piece swimsuit, make custom swimsuit, how to sew swimsuit material



Lastly, here’s how I added the peplum flounce: I measured the waist opening once my top was put together. Then I plugged that measurement into this circle skirt calculator and chose a half-circle skirt, then followed their diagram for cutting my fabric, simply substituting my own desired length (I made mine 5″ long) instead of whatever they gave me. I sewed that piece together up the back and then attached it to the skirt.

A few notes about sewing with swimsuit fabric

*the Sophie pattern has lots of great tips and is definitely beginner friendly for those of us who don’t have a lot of swimsuit making experience. That being said, sewing a swimsuit is definitely not a project for sewing newbies. You’d most likely want some experience sewing with knits or other stretch fabrics before attempting it.

*this project can totally be sewn without a serger and on just a typical regular sewing machine. You’ll be using lots of zig zag stitches (the Sophie pattern even tells you what length and width to set your stitches to).

*buying quality swimsuit fabric is a MUST! I bought all my stash a couple years ago from The Fabric Fairy and have been sewing it down ever since. They have an amazing array of really cute prints and they last 3 times as long as store-bought-swimsuits. The first Cosi suit I sewed for Juliet lasted so long she outgrew it before the fabric wore out. That’s unheard of in Phoenix where we live in the pool and brutal sun all summer long!

I love the look of this halter swimsuit and hope that my tips help you realize just how doable it is to sew your own swimsuit. Let me know if you try it!

Photos by Christie Knight Photography

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1 Comment

  • Reply
    Matching DIY Swimsuits • How to sew womens and girls swimsuits
    September 4, 2019 at 6:01 pm

    […] can see the suit I made for myself last year here and some I made for my girls in the past here and here […]

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