Sew Your Own Swimsuit

Today, I’m sharing some of my best tips and techniques for swimwear sewing and how to sew your own swimsuit. I’ve been sewing my own swimwear for the past 10 years, and I absolutely love it. It’s a great way to get a custom fit, choose high-quality fabrics, and create a swimsuit that’s unique to your style. 

Closet Core Faye Bikini

All the images in this post link to swimwear I’ve made in the past. Click on any of them to see the original blog post with fabric & pattern details.

So, why should you sew your own swimsuit?  

  • Get a custom fit. Swimsuits that you buy off the rack are often not the perfect fit. They may be too tight in some places and too loose in others. When you sew your own swimsuit, you can get the perfect fit for your body. 
  • Choose high-quality fabrics. Swimsuits that you buy off the rack are often made from cheap fabrics that don’t hold up well in the water. When you sew your own swimsuit, you can choose high-quality fabrics that will last for years. 
  • Create a swimsuit that’s unique to your style. You can choose the fabrics, the design and cut, and the finishing details that you love. 

So, now that we’ve talked about why you should sew your own swimsuit, let’s get started! Here are some of my favorite sewing tips that will make your swimwear projects a breeze. 

My Top 5 Swimwear Sewing Tips:

Closet Core Sophie

1. Choose the right fabric:  

When sewing swimwear, it’s essential to select high-quality, stretchy fabrics specifically designed for swimwear. Look for materials with excellent recovery and UV protection, ensuring durability and comfort. I always look for a high UPF factor since the sun is so strong here in Florida.   I love using deadstock and recycled fabric too.

Nautilus Bikini

2. Use Swimwear Elastic:  

I prefer 3/8″ swimwear elastic for leg and side seam insertion, but you can use anything from ¼” to ½”. The type I usually use is made of Polyester 65%/Latex Rubber 35%, but rubber elastic also works well. I look for the best swim elastic I can find so my suits last longer. I keep white and black versions on hand in my stash. I love using wider versions, ½”-2″ for waistbands and straps.  

Ocean Bikini- self drafted

Sewing Straps: 

I take my swim elastic (I like ½”-1”) and then cut my fabric strip double the width plus about ¼”- ½” extra for turn of cloth. Fold in half right side together and place elastic over the top to the far right. You’ll have a bit of excess fabric on the left as you sew. Leave a long tail and sew the length on the serger or with a zig zag or stretch stitch.

*Double the width of Swim Elastic (x2) + an additional ¼”-½” for turn of cloth 

I don’t add any tension as I sew. You don’t want your straps to curl. Turn right side out using a safety pin or fabric turner and you’ll have perfectly stretchy straps.    


Adding leg-opening elastic:  

*Most patterns I’ve used sew swim elastic to the legs in the round, but I prefer flat insertion. Use what works for you!

I attach my elastic to the lining side.  I usually start near the lower crotch edge so bulk won’t be visible and start serging my elastic to the leg opening. I keep my elastic lined up with my cutting foot being careful to not slice through my elastic.

I start with no tension but like to use a bit of extra tension around the curve of the butt and then relax my hold and sew the rest with no added tension. When I get to my starting point, I sew a bit past where I started (approx. 1/2″) and then sew the elastic off the edge. Then I flip my serging to the interior and topstitch in place. I use my Coverstitch machine, but you can use a zig zag stitch.  

My method will add what looks like a slight gather but sits flat when worn. Experiment to get the fit you prefer. I like that small bit of support to keep my suit in place.

Watch the video:

Sophie Purple Tankini

3. Invest in a stretch needle and/or thread:  

Swimwear fabrics can be quite delicate, so using a stretch needle will prevent skipped stitches, fabric damage and give you professional results. I like using a stretch needle but you can also use jersey or ballpoint needles. Go for a high quality polyester thread- I tend to use Gutterman, and I really I love the new stretch threads. They make sewing an entire swimsuit on your regular machine quick and easy. You can also buy specialty feet for elastic insertion for your machine.

 Lekala 4199 Dress Altered to Rashguard
Hooded swim dress

4. Use the right stitch:  

Swimwear can be sewn on a serger or with a regular sewing machine. I tend to sew mine up on my serger and finish on my coverstitch machine but you can just as easily create a swimsuit on a home sewing machine with a zig zag or stretch stitch. These stitches allow the fabric to stretch without breaking the thread.

Most of the time you won’t be adding extra tension as you sew. My general exceptions are the underarm near the bust, under the bust for additional support, curved sections like cutouts, and the backside of leg openings. But that’s my personal preference for fit.

Remember to test your stitch on a scrap fabric to ensure the desired stretch and durability. I always match my threads to my projects. I love sewing up my swimwear on the serger and coverstitch machine since it’s fast and easy. 

Closet Core Faye Tester

5. Focus on Interior Finishes:  

Lining your swimsuit provides support and coverage. Opt for a lining fabric that is lightweight, moisture-wicking, and comfortable against the skin. I look for a smooth silky texture that won’t cling to my skin.

You can self-line your swimsuit with swim fabric for more structure- or even make it reversible. I have made reversible suits, but I still tend to wear them one way. I’d rather make two tops or bottoms in the same fabrics reversed or in slightly different shapes/styles. Closet Core has a Faye tutorial for sewing a reversible swimsuit and I know there are a quite a few tutorials on YouTube.

I also like adding swim cups, either loosely inserted or sewn into the lining. They come in bra sizing. I keep a few nude and black in my size on hand for swimming and bra making. You can also use cut and sew foam available from bra making vendors to make your own if you’ve done some bra making before. This is great for bikini tops with a bra-like cup design.

You can also purchase rings, slides and S hooks for your straps and closures or find and reuse vintage hardware. 


Classes I’ve taken:

Beverly Johnson’s Craftsy Class

Reading List:

  • Pattern Cutting for Lingerie, Beachwear & Leisurewear by Ann Haggar
  • Sewing with Knits, Classic, Stylish Garments from Swimsuits to Eveningwear by Connie Long
  • Kwik-Sew’s Swim & Action Wear by Kerstin Martensson

My newest makes for our trip to Palm Springs:
McCall’s Bikini Modified & Closet Core Faye One Piece

Living in hot & sunny Florida close to the beach my swimwear is on constant rotation. I’ve been sewing swimwear my own swimsuits and rashguards for the last 10 years. I love that I can get a custom fit. I prefer sporty designs that stay put in the waves.  I’m big on sun protection for our entire family and I’m usually pretty covered up with rashy’s, leggings, big hats, and rashguard dresses and caftans.

Centauree~Ava Swimsuit

We live just 15 minutes from our fave beach- Dr. Von D. Mizell-Eula Johnson State Park so we swim pretty regularly. My husband and son both dive and we love kayaking and paddleboarding. We also have a community pool and our Clubhouse Pool (which also boasts a gorgeous golf course, 2 restaurants, meeting rooms and a gym). So my swimsuits get lots of use which is why I sew SO many!

Lady Skater Rashguard Dress
Sarah & Ava Bikini

I love drafting so I design most of my swimwear these days, but I curated a list of some of my fav patterns and designs that have caught my eye.  

Closet Core Faye Bikini in Greece

Have you sewn your own swimsuit before?  What’s your go-to pattern? Let me know in the comments- I’m always on the lookout for new patterns to try out! 

Thanks for joining me today, and until next time, happy sewing. 

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