How to Sew Elastic in Leotards & Swimwear
Learning how to sew elastic in leotards and swimwear is one of the most important techniques for creating professional-looking stretch garments. Swimwear elastic helps leg openings, necklines, and waistlines keep their shape while remaining comfortable and stretchy. This tutorial shows how to sew swimwear elastic into leotards and swimsuits using a simple zig-zag sewing method suitable for regular sewing machines.
How to Sew Swimwear Elastic (Quick Guide)
Swimwear elastic is sewn directly onto the fabric edge and then folded to the inside for a smooth, stretchy finish.
- Join the elastic into a loop
- Mark the elastic and fabric in quarters
- Match and pin the quarter marks
- Zig-zag the elastic to the fabric edge
- Fold the elastic inward
- Zig-zag again to finish
How to Sew Elastic in Leotards and Swimwear
If you are a beginner, then probably the most daunting part of learning how to make your own leotard is sewing elastic in the legs, arms, and neck. Never fear! It is actually quite easy to learn how to sew elastic in leotards, and once you have done it a couple of times, you will wonder why you ever spent money on store-bought leotards and swimwear.
If you are looking for general elastic sewing methods, including waistbands and casings, read the full guide on how to sew elastic for beginners.
These are the instructions for sewing elastic in all my swimsuit patterns and leotard patterns. There may be slight differences in other brands of patterns, so always double-check the instructions before sewing and compare methods.
My photos show you how to sew elastic in leotard legs, but the method for the neck or waist is exactly the same. If you want to learn how to make a leotard or swimwear, then the key items you will need to get a professional result are the right elastic and the right sewing machine needles. Don’t skimp on either of these as you will regret it.
Supplies for Sewing Leotard and Swimwear Elastic
Best Elastic for Leotards and Swimwear?
The best elastic for leotards is swimwear elastic. This elastic is specially treated to be chlorine and sweat resistant and tends to be quite firm. It is typically woven elastic so it doesn’t stretch out when you sew over it.
Most brands come in 1/4 inch (6mm) or 3/8 inch (1cm) widths. The majority of my leotard patterns and swimwear patterns use the 3/8 inch (1.0cm) width as it is easier for beginners to sew over and gives more consistent results. Quality swimwear elastic brands include Birch (Australia), Hemline(UK) and Dritz (USA). Further Reading: Elastic Types Guide
Why Swimwear Elastic is Different
Swimwear elastic is specially designed to resist chlorine, sweat, saltwater, and stretching. Unlike regular elastic, it maintains its recovery even after repeated exposure to moisture and movement.
Needles to Sew Elastic in Leotards and Swimwear
Always use a stretch needle when sewing elastic in leotards and swimwear. Regular needles will give you skipped stitches. Quality brands that manufacture stretch needles include Singer, Klass and Schmetz. Further Reading: Sewing Needle Guide
How to Sew Elastic in Leotards and Swimwear (Step by Step)
Before you start, check out this quick video I made to show you how to sew elastic in leotards. It really is so easy! New videos weekly >>> SUBSCRIBE
Step 1 – Prepare Elastic
Cut the elastic to the length indicated in the pattern. Give the elastic a good stretch, and then double-check the length. Good quality elastic should always return to its original length once stretched.
Overlap the ends of the elastics by 1/2 inch (12mm) and sew it in a circle. Keep the overlap nice and flat by stitching 2 rows as shown. Mark the elastic in quarters. This is easiest to do by folding it in half and then half again.
PRO TIP: Stretching the elastic before sewing helps remove any temporary tightness from packaging.
Step 2 – Marking Quarters
Now you will need to mark the leg hole in quarters. Use the same folding method. I always make the first mark at the crotch then fold and fold again to find the other marks. Mark on the WRONG side of the fabric.
Note that the length of the curve at the front and back of the leg is different so the top mark will not be at the side seam. It will be slightly forward.
Step 3 – Matching Quarters
On the WRONG side of the pants, now match and pin the quarter marks on the elastic to the quarter marks on the leghole. I always try and put the overlap of the elastic at the crotch so no bulk shows through around the curve of the legs. Match the edge of the elastic to the edge of the leg hole. The elastic is slightly smaller than the fabric edge.
Step 4 – Stitch
Zig-Zag around the leg hole with a wide zig-zag stitch (width 6.0 and length 3.0) right in the middle of the elastic. You will need to stretch the elastic out as you sew between the marked points.
Step 5 – Fold and Stitch Again
Now with the pants still the WRONG way out, fold the elastic in by the width of the elastic and zig-zag over the edge with a narrower stitch. (width 4.0 and length 2.0). You will be stitching so the zig-zag goes off the edge of the elastic.
See how on the inside, you will see 2 rows of stitching, but the outside has just one row visible.
Repeat this elastic method for the other leg and neck or waist if required.
How to Sew Elastic in Leotards – Extra Tips
Sewing Elastic in the Waist – The waist is a little easier since it is just straight across. When you divide in the waist in quarters, it will have marks at center front, center back and the side seams.
Sewing Elastic in the Neck – When dividing the neck in quarters, start with marking the center front and center back. Then match these marks and fold in half to get the mid-points. In the majority of leotards or swimwear, the mid-points will not be at the shoulder seams as the front and back neck will usually be different heights.
How to Sew Elastic in Leotards FAQs
When purchasing elastic for a leotard, get at least the size of the armholes, neck, and leg, and add another 10 inches for backup. The actual amount you use will be smaller than the openings. The best width elastic for leotards and swimsuits is 3/8 inch (1cm) wide.
No. Swimwear elastic is specially designed for chlorine resistance and stretch recovery. Learn more about choosing the best elastic types for sewing projects.
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More Leotard Articles
- How to Make a Leotard
- How to sew elastic in leotards
- Lycra and Spandex Buying Guide
- How to Sew Lycra and Spandex on your Regular Sewing Machine
- How to Sew Binding in Leotards
Here are just some of the leotard patterns you can purchase from my Treasurie pattern shop. SHOP LEOTARD PATTERNS
Author - Luisa Clare
Luisa Clare is the founder of Treasurie, a sewing and crochet education platform offering step-by-step tutorials and printable patterns. With over 15 years of experience in dressmaking, pattern design, crochet, and craft education, she specialises in teaching beginners through clear, easy-to-follow lessons. Her tutorials and patterns are used by home sewists and crocheters worldwide to build practical skills and confidence. Learn more about Luisa and Treasurie.
Hi Laura, You will need to remove the old elastic or it will be too thick and uncomfortable. If you are really careful you can unpick the stitching that holds the elastic. Make sure you are in really bright light and have a sharp unpicker. Take your time. It is probably going in a wedge because the width across the crotch is too wide. I’m not sure if you sew but I have a basic leotard pattern in my pattern shop http://www.treasurie.com . Once you get the shape for your daughter perfectly you can make lots of variations.
Hi, My Daughter has a Competition leotard that need to be fixed under crotch/leg fix , is loose and because she is doing a lot of movements , during her routines the leotard Visible wedgie + uncomfortable
I was thinking to change the elastics,
Some tailored people told me that is going to be possible that the Lycra got holes and it will be impossible. So I brought a leotard one size more , so in case I can cut the old part and do it over . What can you recommend?
It is possible to put another elastic more tight over the old one? In the small size leotard?
Most patterns will have a recommendation for cutting.
How do you know how long to cut the elastic?
Most likely the elastic stretched out when zig-zagged over. Try another elastic or cutting it shorter.
Hi Lin, See if it stretches out when worn. If not try cutting the elastic shorter. Make sure your zig-zag stitch doesn’t stretch out the elastic and that you are sewing on the edge.
my elastic does not sit flat leans outward around curve
Hi great tutorial. My elastic around neck edge leans outwards a bit and doesnt sit flat. Any ideas what i did wrong? thanks
Fab, will try that thank you 😉 the rhinestones are no where near the leg elastics, but it’s just taken me a long time to make it, so don’t want to have to scrap it at this stage 🤪
Hi Nixter, This is a hard one if you have rhinestones on it. I think it is a combination of the 3 step zig-zag and not doing it to the edge. A 3 step can stretch out the elastic a bit. Next time a normal zig-zag is better. What about trying a couple of hand stitches in strategic places so it doesn’t show too much inside. This might be better than having to straight stitch. Good luck!
Hi, any suggestions on how to correct leg elastic that keeps twisting back over when worn please ? I don’t really want to unpick as used 3step zigzag stitch but as I’m totally new to this did not sew right up edge of elastic on the inside (did to edge on outside instead ☹️)? Was thinking perhaps just a straight stitch on inside edge of leg elastic to try and keep it in place, but don’t want to ruin it as it looks lovely other to the twisting when it’s on (I have glued 100’s of rhinestones to the leotards already so don’t want to have to restart 🙏
Thanks a million 🙏👍
Hi Teri, All my patterns come with suggested elastic lengths. If you are doing your own pattern, legs are fairly easy. Hold the elastic around the leg where your pattern will end and stretch the elastic to a comfortable length. Add an extra half inch for the overlap.
I am making my own pattern and need help figuring length on elastic.
Hi Kelsey, You don’t normally need elastic in the wrists. Just fold over the hem at the wrist by 1/2 – 3/4 inch and zig-zag over the edge to hold it in place. This can be done flat before you sew the arm seam or last.
For the wrists do you sew the elastic in first and then sew the seam? Or you sew the arm seam and then put the elastic in wrsits?
Hi Cindy, even though the elastic is not in a circle you still have to divide it into quarters (or more) and match it to the quarter marks on your leg. You may also find that it looks better when worn. Once stretched on the body, the fabric and elastic stretch out fairly evenly. Leotards with snaps tend to not look as pretty when lying flat (they call that hanger appeal!) but when worn and the snaps are done up, it should look the same as a regular leotard. Thanks for reading and commenting. Good luck with your sewing. xxDixi
Hi there!! Do you have any tips for sewing an elastic into a leotard that has snaps in the crotch? You can’t sew the two ends together like mentioned above and I’m having some difficulty trying to figure out how to make all the ease look even.