Sewing: Creating a Strappy Back Pin Up Swimsuit

sewing strappy back swimsuit

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how to sew a pin up style swimsuit

Last weekend, I had a super productive time with sewing. I’d been working on my corset kit that Ben bought me for my birthday over the past couple of weeks, and I managed to finish that on the Friday night (super excited to share that with you, but sneak peek here!). I’d got an order from Plush Addict mid week with some excited swimwear fabric that I later found out is actually Liberty (eek!) plus a few extra bits and pieces including a rotary cutter, so I decided to launch straight in that weekend with my new project: a swimsuit.
I’ve previously made a bikini to my Watson set pattern using scuba fabric, but aside from that, I’ve never touched swimwear sewing in my life, so had very little experience with that and was pretty much launching in brand new to this. I could have bought a pattern, but I’d gathered together a few ideas of things I really liked and couldn’t find any patterns that suited what I really wanted to do. The closest I could find was the Bombshell swimsuit by Closet Case Files but it didn’t have the back I wanted and I wasn’t convinced that I would get the right shape across the bust with that – although I am planning to try that one in future now in View A.
So there was nothing for it but to get to work drafting my own! I’d seen Emerald Erin had created her own swimsuit based off a couple of her inspirations, one being the swimsuit that Keira Knightley wears in Atonement, the one that I was taking my inspiration from, so based on that, I had the courage to dive in and sort one out myself. Now you should know something first, I am absolutely no good at anything that involves drawing – I used to get my sister (who is 2 years younger than me) to do my art homework for me at school, I was that useless! So drafting those back pieces with the cut outs was no easy feat, believe me! I redrew those about 15 times before settling on a shape that looked good on paper. And did it work out?

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Well, I guess so! There are definitely a few bits I would change were I to make this again, including making the cut outs on the back slightly smaller, and I would definitely not finish them so close to the edges. I did take the seam allowance into account, but I hadn’t really thought about how much they would need to stretch too, so some of the pieces at the side back are stretched a little too thin for my liking.
As you can see, I didn’t copy my swimsuit inspiration exactly – I ended up having to add in an extra pair of straps and an extra ring at the back after I’d finished putting it all together as I discovered that there wasn’t quite enough support for my bust and found the body of the suit was trying to ride up and over! This did solve the problem, although it’s a bit sad that you don’t get the simplicity of the original design, but it definitely functions better for me with that extra strap in there.
It took me a lot of figuring out how to make the design and put the pieces together, so I ended up drafting 5 different pieces to make up the swimsuit (bodice front, bodice back, cups, modesty panel and gusset). I used my Esther Williams swimsuit as a guide on the sizing for the modesty panel and back bodice, then used the Watson briefs as a guide for the leg openings and gusset. I’m not sure that the modesty panel on this is as ruched and pulled as tight as I’d like it to be, so that’s something else I’d work on next time. The cups though were pretty much entirely hand-drafted by placing bits of tracing paper over my bust and figuring out what shape I wanted – I don’t think it worked out too badly actually!
After cutting out all my pattern pieces, I ended up having to write myself some instructions on how to put everything which took me a good while to figure out in my head first to make sure that all the seams were done in the right order and pieces were attached to the right places. I did also mess up with attached the gusset and gusset lining to get all the seams enclosed so had to unpick and restitch that, but aside from that, I had no major problems with it coming together. I’d planned to use the foldover elastic on all the cup edges, back panels and leg openings, but after using it on the cups and legs, I discovered I’d only just had enough to do those – oops! And that was 3m – never knew I’d need more than that! So all the cut out pieces on the back are self bound with strips from the leftover swimsuit fabric – that was another learning process I had to sort out too!
Like Erin’s version, I created some pockets within the cups where I could add padded cups, but after trying it with and without them, I decided it worked better without, but I have at least got that in there as a little extra lining as it’s fairly sheer when pulled taut. I also included a strip of elastic in the seam under the bust for extra support, although to be honest, I could have sewn this in much more neatly as it’s a bit messy inside at this point. The only other thing I’d do differently is to use a smaller stitch width on my zig zags as there was more stretch to the fabric than I’d anticipated and you can see the stitching on some of the seams.

how to sew a pin up style swimsuithow to sew a pin up style swimsuit

Anyway, what do you think?! I loved making this and am excited to make another now. I think next time I’ll do a simple one without the cut outs in the back – I’d imagine that will be fairly quick to knock up now, although I’ll need to remember to stock up on the foldover elastic this time – oops! Now I just need to wait for my holiday to see whether it will stand up to actual swimming or not!


  1. July 25, 2015 / 4:05 am

    Wow!! This is gorgeous! I’m so happy that I could be part of your courage and inspiration. 🙂 🙂 yay for swimwear sewing!

    • Sian Thomas
      July 30, 2015 / 2:47 pm

      Ah, thank you! Seeing that you’d been able to do it was so helpful for me 🙂

  2. March 27, 2016 / 6:16 pm

    Wow, this turned out so well! I hopped on over to your blog after seeing your suit on Erin’s round up – so inspiring! I attempted a swimsuit a couple of years ago, and it didn’t quite work out. But I remember writing my own instructions was pretty fun. So, maybe this year I will take the plunge and try again…

    • Sian Thomas
      March 28, 2016 / 3:13 pm

      Thank you! Aw no, that’s a shame, but definitely give it another go! This one still wasn’t quite right but felt awesome for my first attempt at a swimsuit – I’m hoping to try another soon 🙂

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