How to Sew a Swimsuit + Free Sewing Pattern | Sew Simple Home
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How to Sew a Swimsuit + Free Sewing Pattern

I have several small humans in my home.  One of these small humans is my daughter.  She is a fashionista.  She loves to dress up, accessorize and be "fancy".  

But she also LOVES to be outside.  One of my biggest concerns with her is her fair skin and red hair.  She burns like a lobster on the 4th of July.  

So I did some research and decided I needed to figure out how to make a rash guard for her.  One that is cute, age appropriate and makes her happy.
Free Kids Rash Guard and Boy Short Pattern

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    That's how I came up with this fun swimsuit design.  Instead of trying to make a rash guard to go over a swimsuit we already have, why not just make the entire swimsuit to revolve around the rash guard!! 

    That's how this boy shorts swimsuit came to be.  Let me tell you how much I LOVE it.  Not only does it keep the sun off  but this pattern expands our modest swimwear patterns.  That is a big plus for me!
    how to make a swimsuit

    If you've never sewn a swimsuit, it might seem a little scary.  Let me start by first giving you some tips and tips for on how to sew a swimsuit.

    swimwear sewing tutorial

     How to Sew a Swimsuit

    If you want to sew swimwear, you need to know a few important tips first.  Why?  Swimwear is not like most sewing projects.  

    The type of fabric is different, the fit is snug and the way it should be sewn may differ from other sewing projects.  Picking the right swimwear fabric can be tricky too.  Let me help you with a few quick tips to get your started.

    Tips for sewing a swimsuit

    1. Get a high quality swim knit fabric.  If you can find one with UV protection, even better!!  

    Most swim knits will be a combination of polyester spandex or nylon spandex this is because they keep their shape.  I get most of my swimsuit fabric from Peekaboo Fabric Shop.

    what are swimsuits made of

    2.  Make sure to have a good stretch in your knit.  Swimsuit patterns are made to fit snug.  If you don't have enough stretch in your knit fabric, it won't fit right and you may not have enough support and coverage.

    3. Use polyester thread.  Chlorine will deteriorate cotton, so choose wisely.

    how to make a swimsuit

    4. Buy swimsuit elastic.  Yep, swimsuit elastic is a thing.  It is also made for use in chlorine and has the right amount of stretch for your projects.

    5. Use an overlock stitch, stretch stitch or a double needle.  You don't need a serger to sew a swimsuit, but it does help.  

    I personally use a double needle to sew my swimsuits.  It gives the suit a nice finish and is a stronger stitch than just a zig-zag stitch.  Learn how to use a double needle in this post.

    diy swimsuit

    6.  Pick the right needle.  You'll want stretch needles.  These will help to ensure you don't snag your fabric as you sew on your sewing machine.  You can find stretch needles on Amazon.

    7.  Follow body measurements NOT just the store bought size.  Sewing a swimsuit that fits well all depends on measurements.  

    Make sure to follow the measurement guide for bust, waist and hips or you'll end up with an ill fitting swimsuit.

    diy bathing suit

    Now that I've shared all my tips for how to sew a swimsuit I want to share my free swimsuit sewing patterns!!  Woot woot!  

    Below are step by step instructions on how to sew a rash guard and boy shorts swim trunks.


    Want the entire Swim Rash Guard and Boy Shorts pattern and full step by step photo tutorial and none of the hassel?  Grab it for $3.97 in our Etsy Shop. No need to access the internet each time you want to make your own.


    Free Swimsuit Sewing Patterns 

    Boy Shorts Swimsuit and Rash Guard Pattern 

    Materials Needed

    how to make a swimsuit
     Step 1
    Place the two shorts pattern pieces with Right Sides Together (RST).  Stitch both crotch seams together.  

    Tip:  Make sure you are using an overlock stitch, double needle or zigzag stitch for both patterns.

    free swimsuit pdf pattern
     Step 2
    Open the shorts up and match the inseams in the center.  Stitch across the seam.

    diy swimsuit
    Step 3
    Turn the shorts right side out and fold the bottom hem of the shorts up ¾”.  Stitch around the hem.  Repeat with opposite side. 

    diy bathing suit
     Step 4
    Create a casing by folding the top of the shorts down 1 ¼”.  Mark a 2” opening to leave open for the elastic.  Stitch around the waistband.

    free swimsuit pdf pattern
     Step 5
    Cut elastic using cutting chart.  Thread elastic through the casing.  Overlap the ends of the elastic 1” and sew elastic together.

    sewing a swimsuit
     Step 6
    Close off the opening in the waistband.  Your boy swim shorts are done!!

    how to make a rash guard
    Step 7
    With RST, match the front raglan rash guard to one of the sleeves.  Stitch sleeve to rash guard.  Repeat with rash guard back and other sleeve.

    how to sew a bathing suit
    Step 8
    Match the raglan back sleeve with the raglan front.  Stitch the sleeve to the front rash guard.

    diy swimsuit

     Step 9

    Lay the rash guard on a flat surface with the wrong side out.  Make sure the side seams match and the sleeves are out to the side.  Stitch down the side seams.

    how to make a rash guard
    Step 10
    Fold the bottom of the rash guard up 1” to make a hem.  Stitch around the hem.

    how to make a swimsuit
    Step 11
    Fold the sleeves up ¾” to make a hem.  Stitch around the hem.  Repeat with opposite sleeve.

    how to make a swimsuit
     Step 12
    With RST, match the short sides of the neckband and stitch.

    how to sew a bathing suit
     Step 13
    Fold the neckband in half making a big circle.  Pin the neckband around the neck with RST making sure the stretch is equal.  Stitch neckband to the rash guard.

    how to make a rash guard
     Step 14
    Turn the neckband up and topstitch around the neckband so it lays flat.

    sewing a swimsuit

    There you have it!  It was a lot easier than you thought it was going to be wasn't it.  

    how to sew a bathing suit

    Ready to try for yourself?  Join our mailing list and we will email you the pattern pieces for the Swim Rash Guard and Boy Shorts Pattern in girl sizes 2-12.

    Learn how to make a swimsuit and what you need to be successful along with a free kids rash guard pattern and boy shorts swim trunks.

    Learn how to make a swimsuit and what you need to be successful along with a free kids rash guard pattern and boy shorts swim trunks.


    1. i think these are great many kids will get swim suits this year ...thank you for putting this up for so many to do this for the kids ...

    2. unless I've printed it incorrectly, there is no neck band piece to cut out. would it be 3/4 of the neck opening allowing for a small seam and deciding the width required? thank you

      1. The neckband cutting chart should be on the pattern pieces. Double check to make sure.

    3. I’m having trouble finding the link to the free pattern for the swimsuit. Can you please help me find it? I’m looking on my phone. Thanks! 😊

      1. Look for the peach colored button at the bottom of the post. It will open up to a window that you enter your email and the pattern will be sent right to you. Enjoy!

    4. Just made this rash shirt and shorts and they are awesome. Thank you so much for the free pattern my Granddaughter is super excited with her new sunshirt and shorts.


    I'd love to hear from you!