How to Sew Swimwear: Essential Tips for Beginners

Making your own swimsuit might sound intimidating, but I promise it's easier than you think. Sewing swimwear has become one of my favourite projects because it's quick, satisfying, and doesn't require fancy equipment. Whether you're planning a one-piece swimsuit or a mix-and-match bikini (have you met our Coralie pattern?), these essential tips will help you tackle your first swimwear project with confidence.

Let's dive into everything you need to know about sewing swimwear at home (pun intended).

Do You Need an Overlocker or Coverstitch Machine to Sew Swimwear?

Here's the best news: you don't need an overlocker (AKA serger) OR a coverstitch machine to sew swimwear. A regular sewing machine with a zigzag stitch is all you need. Yes really.

Swimwear fabric doesn't fray, so there's no need to finish your seam allowances. This makes swimwear sewing much more straightforward than you'd expect. You can leave raw edges on ruffles, hems, and even seam allowances without worrying about them unravelling in the wash.

If you do have an overlocker, feel free to use it on the seams for speed and a professional finish, but it's absolutely not essential. A basic zigzag stitch will do the job beautifully.

Best Needle for Sewing Swimwear

Using the right needle makes all the difference when sewing stretch swimwear fabrics.

I'd recommend using a stretch needle in size 75/11 or 90/14. These needles have a slightly rounded tip that slides between the fabric fibres instead of piercing them, which prevents skipped stitches and damage to the fabric. Stretch needles have more of a pointed shape than ballpoint needles, which are better for regular jersey.

Top tip: Change your needle regularly. Swimwear fabric can dull needles faster than woven fabrics, and a fresh needle helps prevent skipped stitches.

Which Thread Should You Use for Swimwear?

When sewing swimwear, you need thread that can stretch with the fabric without snapping, and that will stand up to sea or swimming pool water.

Good quality all-purpose polyester thread is a good bet. It has a bit of give, is strong, and holds up well against chlorine, saltwater, and sun exposure. Look for good-quality polyester thread in a colour that matches or complements your fabric.

You could also try specialist thread that has a little added elasticity, such as Gutermann Maraflex.

Avoid using cotton thread for swimwear. It's weaker, so could snap when the fabric is pulled, or can degrade in the water.

Stitch Settings for Sewing Swimwear

Getting your stitch settings right is key to professional-looking swimwear.

Here's what I'd suggest:

• Stitch type: Zigzag stitch
• Stitch width: 3.0 (wide enough to catch both sides of the fabric, but not too wide)
• Stitch length: 2.0 (shorter stitches provide more stretch)
  

Before you start on your main fabric, always test your stitch settings on a scrap piece of the swimwear fabric you're using for your project. Pull the seam gently to check it stretches without the thread snapping or the fabric puckering.

Choosing the Right Fabric for Swimwear

Not all stretch fabrics are suitable for swimwear, so here's what to look for.

Your main fabric needs to be a four-way stretch swimwear fabric. This is usually a blend of nylon or polyester with elastane (also known as Lycra or Spandex), designed to handle water, chlorine, and sun exposure without losing its shape. "Four-way" means it stretches vertically down the body as well as horizontally across it - important for a fitted swimsuit or bikini.

It's important to check the pattern you're using for the minimum stretch percentage needed, to ensure your beautiful creation doesn't end up too tight. For our Coralie swimsuit and bikini sewing pattern, we recommend fabrics with at least 50% stretch in both directions. 

For lining, you can use:

• Swimwear lining fabric (often sold alongside main fabrics)
• Stretch mesh
• More of your main fabric (in a pinch)

Make sure your lining also has the minimum recommended stretch for your pattern in both directions.

What about regular jersey or other knitted fabrics? I wouldn't recommend it. These fabrics aren't designed to hold up in water and can sag, stretch out, or deteriorate quickly.

Working with Swimwear Fabric: Tips and Tricks

Swimwear fabric can be slippery and stretchy, which can feel tricky at first. Here are my favourite tips for handling it like a pro:

1. Don't stretch as you sew
   Let the fabric feed through the machine naturally without pulling or stretching it. Pulling causes wavy, distorted seams. Also try not to let the fabric hang off your sewing table.
   
   
2. Use a walking foot (optional but helpful)
   A walking foot helps feed both layers of fabric evenly, which is especially useful when sewing slippery swimwear fabric. It's not essential, but it makes life easier.
   
   
3. No need to press!
   This is my favourite part. Using an iron can damage synthetic fibres in swimwear fabric, so skip the pressing. Just finger-press seams open if needed, and they'll sit flat once the garment is on.

Troubleshooting Common Swimwear Sewing Problems

Even experienced sewists hit snags when sewing swimwear. Here's how to fix the most common issues:

Skipped stitches

Cause: Wrong needle type or a dull needle
Fix: Switch to a fresh stretch needle

Puckered seams

Cause: Tension too tight or fabric stretched while sewing
Fix: Reduce tension slightly and let the fabric feed naturally

Thread snapping

Cause: Thread isn't stretchy enough or tension is too tight
Fix: Use polyester thread and reduce tension

Fabric slipping

Cause: Swimwear fabric is slippery by nature
Fix: Use a walking foot or slow down and guide gently

Ready to Sew Your First Swimsuit?

Sewing swimwear is quicker, easier, and more rewarding than most people expect. You don't need specialist equipment, the fabric requirements are small, and the sense of achievement when you wear your handmade swimsuit is unbeatable.

If you'd like step-by-step video guidance to walk you through the entire process, our Learn to Sew Swimwear online workshop is perfect for you. You'll learn how to sew a swimsuit or bikini from start to finish, with detailed lessons on techniques, fit adjustments, and gorgeous pattern hacks to create even more styles.

The workshop includes the Coralie swimsuit and bikini pattern (sizes UK 6–34), so you'll have everything you need to get started.

Ready to make a splash? We can't wait to see what you create!