Swimwear Elastic: Everything You Need to Know

One of the most common categories of questions when it comes to sewing swimwear is elastic. What is it, how do you sew it, why is it such a pain sometimes? In this post we're aiming to answer every question you might have about elastic for DIY swimwear.

On YouTube we'll be doing a three part series that answers these questions and more. If you prefer to watch the video, you can find them below.

Part 1: The Most Common Questions + Before You Sew

COMING SOON Part 2: While You Sew + Demo

COMING SOON Part 3: The Final Product + Troubleshooting

the most commonly asked questions

Do you need elastic?

I’m going to answer this question from two different views, because honestly it depends.

First, the “proper” sewing view. Technically speaking, you should always use elastic in your swimwear. This is because the elastic serves an important purpose, and that purpose is helping the garment keep its shape. The actual fabric will stretch over time, but it’s the elastic that keeps everything in place. Elastic also helps the garment sit nice and flat so seams don’t roll over. On top of all that, having elastic in your swimwear looks and feels more professional, so if you’re selling swimwear that’s definitely something to consider.

Now I’ll discuss circumstances where you don’t “need” elastic. There are a few common complaints on why people don’t want to use elastic, and honestly it’s your choice. Sure, technically speaking using elastic is the correct way. However, at the end of the day it’s your choice.

Some people don’t like the feeling of elastic. It can feel constricting and some people just prefer a looser fit. There are others who don’t have the means to get elastic, usually because they can’t find any that ships to their country. Then there’s the people who aren’t worried about being proper quite yet, they just want to sew a bikini!

So I say just do what works for your situation!

What width of elastic should you use?

This is a little bit of personal choice and a little bit of “depends what you’re doing”

I use ¼” elastic for pretty much everything

If you'd like added support you can use 3/8”. I only really use 1” for bands, extra supportive straps, or for thick straps just for stylistic choices.

I’d say if you had to choose one size of elastic for every project, I’d go for ¼”!

what kind of elastic should you use? rubber, braided, or clear?

This is going to be another answer with a technically correct answer, but another “do what you want” situation.

Rubber elastic is the best elastic for swimwear. It holds up the best in terms of tension, plus it’s resistant to chlorine, salt water, UV, and sun tan oils.

Everything I’ve come to learn has said that braided elastic doesn’t hold the same tension as rubber, and it’s not suitable for swimwear purposes. However, I like to buy swimwear from big brands and take them apart to see how the manufacturer constructed the piece. And lately I’ve been seeing a lot of braided elastic! So I don’t know anything about where to find it but apparently there is braided elastic out there these days that can work for swimwear.

Finally, clear elastic. People really like this stuff, but unfortunately out of all three it seems to be the one to break down the quickest, especially when it comes to UV

So bottom line, rubber elastic is the best I’ve found, but if you do come across braided that’s meant for swimwear then go for it

before you sew

What type of needle and thread should you use to sew elastic?

For thread you can use regular polyester thread, just make sure it’s high quality.

With cheap thread you really do get what you pay for, so if you’re having issues with your machine then it’s possible cheap thread could be the reason

For needles I’d recommend using either ballpoint or stretch needles. I’ve read that stretch needles are the best specifically for elastic!

Make sure you change out your needles after 24 hours of using them or whenever you start to notice problems with your stitching.

WHERE TO buy swimwear elastic

This depends on whether you want to buy a bunch of elastic or just a little.

For small quantities I’d recommend shopping on Etsy.

I started a sister company for Edgewater Avenue called Swimwear Notions USA, and over there we sell elastic in small and medium quantities. The smallest I sell is 10 yards and I also sell by the pound which will get you several hundred yards.

There are of course other places you can get elastic from, so below are a few shops where Edgewater customers like to buy their elastic from!

1. Swimwear Notions USA (supports Edgewater Avenue & sustainable packaging/shipping!)

2. Sew Sassy

3. Coast Pad

4. DIN Fashion Supplies

Parts 2 & 3 Coming Soon!