Tuesday, July 16, 2019

Reversible Cottesloe Swimsuit

Reversible Swimsuit!? What? Yes, it’s true. Just when you thought I didn’t need any more swimsuits, now I have two in one!

When I was a kid, I had a swimsuit that was reversible. It was all black on one side and all white on the other. I thought it was so awesome that I could pack one suit, take it to camp for a week, and essentially have two suits. Probably no one noticed. But it was still my favorite anyway.

A few months ago, The Fabric Fairy expanded their team of sewists and I was one of the lucky ones they picked. If you’ve been reading long at all, you know TFF is hands-down my number one choice for swim fabrics. I’ve also used their French terry, jersey, etc. over the years. When it came time to choose fabric for my first Fabric Fairy project, I tried desperately to avoid more swimwear. How many suits does one person need?? I usually make one every year, and I’d already done that! But I’m like a helpless baby. Especially when I hit on the idea to make a reversible suit!

One side of the suit is this Supernatural Nylon Spandex Swim. The other is Classic Black Nylon Spandex Swim. Pro tip: when in doubt about the success of a swimsuit, use black. Any wonky stitching will disappear. I adore the print, but let me tell you, the black is one of the highest quality swim knits I’ve ever used. Highly recommend!

The pattern I used for this suit is the Megan Nielsen Cottesloe. As far as I know, this is the first MN patten I’ve used. True story, I’m in love with this pattern. Lately, I’ve developed an intense bond with super simple patterns done really well, and the Cottesloe falls into that category. The cut is perfect.

My measurements put me at a size 2-8-8. The last time I tried to make a one piece suit, it ended up too short in the torso and got chopped into a two piece. Given my drastic grading and past issues with one pieces, I made a quick muslin of the Cottesloe. It fit, but after comparing the stretch of my muslin and final fabric, I decided to add 1/2” of length to the bodice. I have a long torso and this is a common adjustment. Especially considering that I have two different fabrics stretching together, I'm really glad I added the extra length. The fit is amazing! My muslin was the low-back version, but it felt like my shoulder straps could easily get pulled off, so I went with View B.

I went with the Cottesloe because of its simplicity, which is necessary for a reversible suit. The pattern simply has elastic sewn to the edges and then turned down. To make it reversible, instead the edges are finished in the same way you would use double-fold bias tape, except that there is also elastic inside. I chose a solid black and a black and white print so that I could use one of them as the binding, and it would work with both fabrics.

To make a reversible swimsuit, cut a front and back from both fabrics. Construct them as usual and then insert one into the other, WRONG sides together.

The seam allowance on the Cottesloe is 1/4" (side note--I generally hate this SA on a swimsuit. 3/8" is much easier to work with and where I am 3/8" swim elastic is easier to find). The method I used means that the finished edge of the suit will be the same as the cut edge. So, the seam allowance needed to be removed for the suit to fit as intended. The easiest way to do this is to serge your pieces together along all the openings, cutting off 1/4". That way, you can both baste your pieces AND remove the seam allowance in one quick pass. I was pretty lazy with my suit and I only did this step on the leg openings. It didn't matter to me if the other openings were slightly larger, but nobody wants an extra-large crotch amiright? Additionally, I did use 3/8" elastic instead of 1/4" as directed, so it came out smaller anyway. Too much maths.

Next, I used a flexible ruler to measure the length of the openings. I cut 2" fabric strips in this length. The Cottesloe gives tons of details on lengths for the elastic but I have enough experience with swimwear that I can figure it out by feel. If you do not, then use the pattern measurements, or the length of the opening minus a little.

Sew your 2" binding strips along the short ends so that they make a loop. Do the same with your elastic. Quarter and pin in this order: swimsuit right side (either right side) touching binding right side, elastic touching binding wrong side. Go slowly, making sure you're catching all the layers and that they all line up along the raw edges. I used a zig-zag on my regular machine to make sure I didn't screw up this step. Sew straight down the middle of the elastic or to the side furthest from the raw edge. You'll be stretching the binding and elastic slightly to ensure a snug fit.

Next, you will wrap the binding around the elastic to the other side of the suit, tucking the raw edge under and thus covering all the finishings. This is the part that is similar to double-fold bias tape. The difference is that cotton bias tape is easily pressed into submission, and swim knit is not. Be careful not to roll the elastic out of place, or to let the raw edge of the binding slip out. Use lots of Wonderclips if you have them! Topstitch the binding down using a zig-zag stitch. Normally, I would use my coverstitch to topstitch swim, but remember that the stitching will be visible on both sides of the suit. A zig-zag is better in this case. Repeat this process with all of the openings and viola, a swimsuit that is completely finished no matter which side is out!

Questions? Comments? Drop them below!

I received this fabric for free in exchange for a review. I purchased the pattern. All opinions are my own. Affiliate links have been used in this post. Thank you for supporting this blog!


  1. How have I never heard of a flexible ruler before?!? So cool! I love your reversible suit and the binding technique. My trick/go to for swim is to use tons of wash away wondertape, it helps for things like the binding that can’t be ironed into place.

  2. Thanks for sharing, I have thought about doing that now I can I hope.

  3. So clever! I did not know reversible swimsuits existed!

  4. Your prowess in this blog post about SWIMWEAR is truly remarkable! I've been on the hunt for wrap swimsuit and stumbled upon your incredible post. Your work truly stands out.


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