How to Sew Your Own Swimsuit with Katie Kortman

Sewing your own swimsuit is a great way to create a unique, one-of-a-kind piece that fits your body perfectly. Follow the tips below to create your own DIY swimsuit.

Katie: It’s July. It’s hot. You just want to stay inside but if you must go out, there needs to be water, am I right? If you like to sew, you may have thought about sewing your own super cute, totally flattering swimsuit in a fabric more exciting than what is offered at the store. But you’re scared. I have heard people tell me this time after time. I get it. Until last summer, I was the same way. I could sew pants, dresses, shirts… anything! But a swimsuit? No, I must not be skilled enough for that. Or the dreaded thought… what if something malfunctions when I get into the water?

I am here to tell you that all those fears are for nothing!! If you can follow a pattern and know how to sew a zig-zag or straight stitch, then you can sew a swimsuit! 

Already a pro at sewing swimsuits?
Check out this post to see which swimsuit patterns and fabric designs I’m loving this summer.

There are many types of swim fabrics to sew with, but today we are going to talk about Spoonflower’s Sport Lycra. This post has tips that you can apply to sewing anything with Sport Lycra, even athletic wear!

I found this fabric to be the easiest to sew of all the bathing suit fabrics I’ve worked with. It is actually easier than most cotton knits I’ve sewn because it is thick and not slippery as you sew (and swimsuits are more forgiving than say… the hem of a stretchy knit shirt). 

Spoonflower Sport Lycra is durable and stretchy, making it a great fabric to work with when you sew your own swimwear. Featuring knit/jersey construction and a fabric content of 88% polyester and 12% Invista Lycra, this fabric comes in a variety of colors and patterns to help you build a swimsuit that appeals to your unique sense of fashion and style.

Today I’m going to give you tips for sewing swimsuits with Spoonflower’s Sport Lycra but for general tips on sewing with knits, be sure to check out this blog post! I have now sewn 13 swimsuits with the lycra and I can confidently say this fabric holds up to all the elements!

Needle: You will want to use a ballpoint/ jersey/ stretch needle in your machine. 

Pins and clips: Both work, but I found clips quicker and preferred them because it meant less holes in the fabric.

Thread: Polyester – avoid cotton thread! I have used Eco-flex, wooly nylon (in the serger – and you just do the two loopers), Coats and Clark poly (all purpose) and finally Gutterman Poly. I prefer Gutterman thread in my sewing machine because I’ve had the least amount of breakage and skipped stitches when using that thread. I still do like the wooly nylon in my serger but its not totally necessary. 

Scissors or Rotary Cutter: If you have the space, a mat and cutting table, use a rotary cutter on your lycra because it will ensure a more precise cut. You can also just use your sharpest scissors and cut on the floor. Work with what you’ve got!

Pattern weights: Again, you can pin the patterns, but the best way is to use pattern weights and rotary cutter to prevent piercing the fabric and to get a more precise cut. I did use the weights as opposed to the pins in these five swimsuits and I prefer them to pinning the pattern down. 

Swim Elastic: Swim elastic is made to withstand chlorine and salt water. You can get it online or in most big-box fabric stores. I ordered a huge roll of it so I didn’t keep running out. 

Because the Sport Lycra is thick and opaque, many prints won’t need any lining, especially if it’s for a child’s swimsuit. I chose to line all of these suits since they were for adults. You will want a nude, white or black swim lining (two fabrics on the left) depending on the designs you’ve chosen on Spoonflower. 

You can also get something called Power Mesh which is found near the swim fabrics at big-box stores and online (two fabrics on the right). It is used to hold in the bust and/or tummy and can be sewn to the lining so it acts as one piece of fabric. Many patterns will mention its use in the instructions.

Pro tip: Spoonflower’s Sport Lycra also works great for lining your swimsuit. For an added bonus, choose a coordinating print from your main swimsuit fabric.

Because a swimsuit is meant to confirm to your body, the best stitch to use when sewing is a stretch stitch such as the zigzag, triple zigzag or lightning bolt stitch.

During this project you will be working with negative ease, which means the pattern is written slightly smaller than your measurements so that it can be tight and stretch to fit your body. Because of that, you need to use stitches that can stretch and not break. The photo below shows four stitches/methods you can use to sew your swimsuit.

When you’re ready to sew your swimsuit, follow these simple steps: 

Once your pieces are sewn together, double-check your stitching and remove loose strands. Once done, you’ll have a brand new, custom-made swimsuit to wear.

The photo below shows a method of elastic insertion that I hadn’t seen in other patterns. You simply put the elastic ⅛” in from the edge of the serger so it cuts off the excess fabric but the serging stitches encase the elastic as it sews! Most patterns just have you zig-zag the elastic to the seam allowance and cut off the extra ⅛” which also works great.

Sewing your own swimwear is actually relatively easy, provided you have some experience working with a sewing machine. Patterns are readily available online or you can create your own.

Depending on your pattern and level of experience, you should be able to sew a swimsuit in as little as three to four hours.

Most swimsuit patterns require less than a yard of fabric. Typically between 0.5 and 0.75 yards is enough.

The cost of making your own swimsuit varies depending on your fabric choice but the good news is that it’s nearly always less expensive than purchasing one in stores. 

Now that you know the ins and outs of sewing your own swimsuit, find out how to choose the right fabric design and swimsuit pattern!

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