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[BAW33]: Top 5 Tips for Sewing Swimwear

Aug 14, 2016 | Tutorials | 15 comments

Hi All!

This week I’m going to share some of my favourite Swimwear Sewing Tips! I sew A LOT of swimwear, and *whispers* it’s my favourite thing to sew– but bras are a close second! And to be fair to my bra sewing – most of my bathing suits have bras in them!

So this post is all about my 5 Top Tips for sewing swimwear, some of these are collected from my past posts, and some of them are just little tips that  haven’t mentioned yet. Here we go!

1. Quality Thread

When I was a kid, my mom made all my bathing suits, and I remember pulling my bathing suit out of my drawer a couple months after summer, (usually right before I needed it to go somewhere) and hearing the little ping of sad and worn out thread snapping in a million little places as I tested the leg elastic. The thread was always the first to go- thread, elastic, and then the fabric.

One thing that I’ve discovered that has completely changed my sewing is high-quality thread. It works better in your machine, it looks better, and it lasts SO much longer. For swimwear I recommend polyester thread (since cotton will hold moisture), and specifically I use the Mara 120 thread from Gütermann, which is an industrial polyester thread. I also use it on all my bras too- once you get the luxury of nice thread, well you just can’t go back!

I will be selling this thread very soon in my Etsy Shop!!

2. Binding Edge

This is a real favourite of mine. I find so often swimwear is always the same type of edge sewn with elastic- which is great- but sometimes for a really neat finish- you can’t beat binding. Binding is great if you want an edge that is not too tight- like if you’re making a more cheeky style bottom (or even if you’ve tried on your suit and find that it’s just a little too tight for you around the legs or waist like I did with this navy medium rise bottom!)

It’s also great when you’re working with foam to reduce bulk, and when you’re working with a variable neckline (the top of a round cup- over channeling, around to the back)! Like in this bra bathing suit.

photo by my AMAZING friend – Veratography

Apart from these reasons, it’s also fantastic to add a little pop and coordinate your colours like I did on my most recent suit- that nice little black edge!

3. Put your Bra in your Bathing Suit

This is an Emerald Erin classic. Nothing feels as good as a bra in your swimsuit- no worrying about your nipples showing, it’s way more flattering, and feels so much more secure on.

There are so many ways that you can put a bra into a bathing suit:

like simply making your bra with foam and swimwear and wearing it as your bikini top (I have some tips on working with foam and bras here)

But you can also make a one-piece with cups which is oh-so-cute! Tutorial here!

Or you can turn your bra into a tankini using this tutorial here!

4. Use Elastic in your Swimwear Straps & Strings!

I’ve seen a lot of bikinis where the string is simply a tube of swimwear fabric. The problem I find with this is: it’s not feel very secure on your body unless you pull them REALLY tight, and then if you do pull them REALLY tight- chances are you’re going to snap some of the threads holding them together. I much prefer to use a 3/8″ all-rubber swim elastic and wrap it in my swimwear. They feel SO secure, and with the strength of the elastic, you know you’ll never just completely pull them out- they bounce back!

I know two good ways to sew your swimwear strings! And I did a tutorial on them here 🙂

5. Take Care of your Swimwear!

This seems obvious, but I’m still a victim. One story comes to mind- over a year ago now I was heading to California for a vacation to visit family. I had made a cute bathing suit– a bralette style top with a cool pattern with bright neon coral, and neon coral bottoms to match. I was in the hotel – flight leaving in the morning- and we were all ‘let’s jump in the hot tub’…. you can see where this is going. About 5 minutes into the hot tub time, I look down to see that all of the neon coral in my swim top is now purple, and I got out to realize that a similar effect happened to my bottoms. Only the bottoms were solid neon coral before, and now they were a faded neon coral anywhere they were tight and touching my skin, but anywhere there were they weren’t (think a strip up the center back) was now a murky purple colour.

That concluded in a very disappointed me, doing a midnight run to the closest/cheapest spot I could find for a plain pair of black bottoms.

So what I have learned is: DO NOT wear your beautifully hand-crafted swimwear in a hot tub (especially not a hotel hot tub), rinse you’re bathing suit immediately after being in chlorine to help save the elastic for longer, and don’t throw your bathing suits in the washing machine- gentle soaps, and let it air dry!

So those are my Top 5 Tips!

What are your favourite tips for sewing swimwear?

Talk to me in the comments!




  1. Diana Nuland van

    thanks for sharing Erin, your tips are very usefull and inspiring

  2. MarianneG

    Hi Erin ! LOVE your newsletters ! Do you sell the binding that you were talking about on your Navy suit ? tia !

    • EmeraldErin

      Thanks Marianne! I actually use a self-binding by taking a strip of the same fabric the bathing suit is made from and using it to bind the edge- always a perfect match!

  3. Anonymous

    Hi Erin,
    As usual super useful info. About washing your suit or not in a machine. I started sharing responsibility for the laundry at about the same time I got my first bra. It was just Mom and me, thank goodness she was smart about garment care. We hand washed and hung dry bras. Swimsuits however we always bagged and washed out (on delicate ) ASAP in the machine. Maybe we were lucky but I know she was wearing some suits that were over ten years old! I out grew most of mine or just got tired of them. Knock on wood. 🙂 I think the gentle soap is also super important. We both had sensitive skin so thats all we had. No brighteners for sure and no fragrence either. I almost forgot, we always rinsed our suits as soon as we took them off. Changing room or bathroom sink where ever a quick rinse could happen.
    Thanks as always,

    • EmeraldErin

      Great comment Merry! And I completely agree- I think the soap makes SO much difference, rinsing immediately and I also think (depending on your washing machine) it can be okay sometimes to bag and wash on delicate. 🙂 My other trick to making swimwear last longer is making so many, that you only really have a chance to wear each one a couple times a season! ha ha! xo

  4. Abbey Dabbles

    Just made my first swimsuit this weekend and look how handy these tips turned out. Next one will definitely be getting a bra insert though. Didn't have enough time to put a proper bra in it and ended up wearing a regular one underneath, just for my own peace of mind. Although huzzy said I looked okay without it. But you know how much that extra security means…

    • EmeraldErin

      A bra in a bathing suit is really just the gold standard of swimwear comfort! I'd love to see your swimsuit!! 🙂 🙂 xo

  5. Unknown

    Two questions:
    Do you use a binding foot?
    About that cropped swimshirt….Can you use a t-shirt pattern and if so, how should the t-shirt fit before converting it into a swimsuit?
    It's for my daughter who hasn't figured out yet that the picture on the pattern envelope is only a starting point. I have a t-shirt pattern that fits her as a t-shirt and would like to adapt it.
    I am loving your swimsuit posts….

  6. Andrea

    Erin, your bathing suits are gorgeous! Love that navy set!

  7. Gwen

    I am slowly getting into sewing my own swimwear because I am sick and tired of searching for the “perfect” vintage Catalina bathing suit. Why buy one when I can make my own right? I have been sewing with wovens for years and years, and sewing something stretchy scares the hell out of me. I think I will be lurking around your blog a little bit before I make the jump! Thank you for everything you have put on your blog! x Gwen

    • Emerald Erin

      Yay! And I totally agree! – also I’m not lusting after a vintage Catalina bathing suit now! Good luck on your stretch sewing journey (I promise stretch fabrics are amazing!!) & please share your progress!

  8. Brittany

    Erin thanks for the tips! I’m venturing into swimwear sewing right now starting with a bra pattern I’m modifying into a bikini top. I’ve been reading all I can from your site learning as much as I can as I plan out my process. Thank you for sharing your gifts!

    • Emerald Erin

      Happy to help 🙂 Thanks so much for your comment 🙂


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